Example of C# Smart Differencer Output

This page contains an example of the output generated by SD's C# Smart Differencer tool
when applied to an original file and an updated version of the same file.

Output from C# Smart Differencer on original and updated file

This page contains an example of the output generated by SD's C# Smart Differencer tool.
Observe that the Smart Differencer produces only 16 lines of output, compared to diff's 197 lines of output; the programmer simply has to look at less code. Note the added precision of Smart Differencer output: precise deltas with line and column number (l.c) ranges, rather than simple line deltas, and renamed variables ('oldname' ->'newname'). Notice that source code formatting (different line breaks in line 342-442) don't fool the smart differencer, that changed comments don't confuse it, and that radix changes on the numeric constant (in lines 14-18) are ignored.
For comparison, see deltas generated from a standard diff tool.


Insert 117.52-117.53
>                                                   +3   
Insert 183.41-183.90 copying 437.32-437.45 to 183.58-183.71 with 'ToString'~>'first' and 
	'buf'~>'schema'
>                       isSchemaQuoted = schema.first() == QuoteCharacter;
Rename 231.33-262.33 to 233.33-264.33 with 'uniqueKeys'~>'unique_keys'
Insert 333.127-333.131
>                                                        =NULL 
Delete 374.41-377.41 merging 374.46-374.83 into 382.37-382.69 with 'DefaultValue'~>
	'Comment', merging 376.49-376.78 into 569.41-569.72 with 'buf'~>'alter', 
	and merging 376.80-376.95 into 366.45-366.58 with 'DefaultValue'~>'IsNullable'
<                    if (!string.IsNullOrEmpty(col.DefaultValue))
<                        {
<                         buf.Append(" default ").Append(col.DefaultValue).Append(" ");
<                        }
Delete 571.33-571.71 moving 571.33-571.71 to 539.33-539.71
<                                columns[column.CanonicalName] = column;
Insert 539.33-539.71 moving 571.33-571.71 to 539.33-539.71
>                                columns[column.CanonicalName] = column;

Output from Cygwin diff tool

Note absence of column number data, absence of identifier rename detection, failure to recognize reformatted code as unchanged (diff thinks the block of code at lines 342-442 has changed), failure to notice same numeric values in the face radix change (lines 14-18), and failure to ignore comments.
See the actual deltas generated from C# Smart Differencer.
See original file and updated version of the same file.


15,18c15,18
<               Drop = 1,
<               Update = 2,
<               Export = 4,
<               Validate = 8,
---
>               Drop = 0x1,
>               Update = 0x2,
>               Export = 0x4,
>               Validate = 0x8,
60,77c60,78
<               /// <summary>
<               /// Gets or sets the name of the Table in the database.
<               /// </summary>
<               /// <value>
<               /// The name of the Table in the database.  The get does
<               /// not return a Quoted Table name.
<               /// </value>
<               /// <remarks>
<               /// <p>
<               /// If a value is passed in that is wrapped by <c>`</c> then
<               /// NHibernate will Quote the Table whenever SQL is generated
<               /// for it.  How the Table is quoted depends on the Dialect.
<               /// </p>
<               /// <p>
<               /// The value returned by the getter is not Quoted.  To get the
<               /// column name in quoted form use <see cref="GetQuotedName(Dialect.Dialect)"/>.
<               /// </p>
<               /// </remarks>
---
>               /* <summary>
>                   Gets or sets the name of the Table in the database.
>                   </summary>
>                   <value>
>                   The name of the Table in the database.  The get does
>                   not return a Quoted Table name.
>                   </value>
>                   <remarks>
>                   <p>
>                   If a value is passed in that is wrapped by <c>`</c> then
>                   NHibernate will Quote the Table whenever SQL is generated
>                   for it.  How the Table is quoted depends on the Dialect.
>                   </p>
>                   <p>
>                   The value returned by the getter is not Quoted.  To get the
>                   column name in quoted form use <see cref="GetQuotedName
					(Dialect.Dialect)"/>.
>                   </p>
>                   </remarks>
>                 */
116c117
<                       get { return columns.Values; }
---
>                       get { return columns.Values+3; }
181a183
>                                       isSchemaQuoted = schema.first() == QuoteCharacter;
231c233
<                               if (uniqueKeys.Count > 1)
---
>                               if (unique_keys.Count > 1)
236,237c238,239
<                                       var finalUniqueKeys = new Dictionary<string, 
UniqueKey>(uniqueKeys.Count);
<                                       foreach (var entry in uniqueKeys)
---
>                                       var finalUniqueKeys = new Dictionary<string, 
UniqueKey>(unique_keys.Count);
>                                       foreach (var entry in unique_keys)
261c263
<                                       return uniqueKeys;
---
>                                       return unique_keys;
331c333
<               public string SqlCreateString(Dialect.Dialect dialect, IMapping p, 
						  string defaultCatalog, string defaultSchema)
---
>               public string SqlCreateString(Dialect.Dialect dialect, IMapping p, 
					string defaultCatalog, string defaultSchema=NULL)

342,345c344,345
<                       if (HasPrimaryKey && identityColumn)
<                       {
<                               foreach (Column col in PrimaryKey.ColumnIterator)
<                               {
---
>                       if (HasPrimaryKey && identityColumn) {
>                               foreach (Column col in PrimaryKey.ColumnIterator) {
347,348c347
<                               }
<                       }
---
>                       }}
351,354c350,351
<                       foreach (Column col in ColumnIterator)
<                       {
<                               if (commaNeeded)
<                               {
---
>                       foreach (Column col in ColumnIterator) {
>                               if (commaNeeded) {
361,362c358
<                               if (identityColumn && col.GetQuotedName(dialect).Equals(pkname))
<                               {
---
>                               if (identityColumn && col.GetQuotedName(dialect).Equals(pkname)) {
364,366c360
<                                       if (dialect.HasDataTypeInIdentityColumn)
<                                       {
<                                               buf.Append(col.GetSqlType(dialect, p));
---
>                                       if (dialect.HasDataTypeInIdentityColumn) { 
											buf.Append(col.GetSqlType(dialect, p));
368,371c362,363
<                                       buf.Append(' ').Append(dialect.
GetIdentityColumnString(col.GetSqlTypeCode(p).DbType));
<                               }
<                               else
<                               {
---
>                                       buf.Append(' ').Append(dialect.
GetIdentityColumnString(col.GetSqlTypeCode(p).DbType)); }
>                               else {
374,386c366,368
<                                       if (!string.IsNullOrEmpty(col.DefaultValue))
<                                       {
<                                               buf.Append(" default ").
Append(col.DefaultValue).Append(" ");
<                                       }
<
<                                       if (col.IsNullable)
<                                       {
<                                               buf.Append(dialect.NullColumnString);
<                                       }
<                                       else
<                                       {
<                                               buf.Append(" not null");
<                                       }
---
>                                       if (col.IsNullable) {
>                                               buf.Append(dialect.NullColumnString); }
>                                       else { buf.Append(" not null"); }
389,396c371,373
<                               if (col.IsUnique)
<                               {
<                                       if (dialect.SupportsUnique)
<                                       {
<                                               buf.Append(" unique");
<                                       }
<                                       else
<                                       {
---
>                               if (col.IsUnique) {
>                                       if (dialect.SupportsUnique) { buf.Append(" unique"); }
>                                       else {
398,399c375
<                                               uk.AddColumn(col);
<                                       }
---
>                                               uk.AddColumn(col); }
402,403c378
<                               if (col.HasCheckConstraint && dialect.SupportsColumnCheck)
<                               {
---
>                               if (col.HasCheckConstraint && dialect.SupportsColumnCheck) {
407,410c382
<                               if (string.IsNullOrEmpty(col.Comment) == false)
<                               {
<                                       buf.Append(dialect.GetColumnComment(col.Comment));
<                               }
---
>                               if (string.IsNullOrEmpty(col.Comment) == false) { 
									buf.Append(dialect.GetColumnComment(col.Comment));
 }
412,414c384
<                       if (HasPrimaryKey)
<                       {
<                               buf.Append(StringHelper.CommaSpace).
									Append(PrimaryKey.SqlConstraintString(dialect, defaultSchema));
---
>                       if (HasPrimaryKey) { buf.Append(StringHelper.CommaSpace).
									Append(PrimaryKey.SqlConstraintString(dialect, defa
ultSchema));
417,418c387
<                       foreach (UniqueKey uk in UniqueKeyIterator)
<                       {
---
>                       foreach (UniqueKey uk in UniqueKeyIterator) {
422,423c391
<                       if (dialect.SupportsTableCheck)
<                       {
---
>                       if (dialect.SupportsTableCheck) {
427,428c395
<                               }
<                       }
---
>                               } }
432,435c399
<                       if (string.IsNullOrEmpty(comment) == false)
<                       {
<                               buf.Append(dialect.GetTableComment(comment));
<                       }
---
>                       if (string.IsNullOrEmpty(comment) == false) { 
							buf.Append(dialect.GetTableComment(comment)); }
571d534
<                               columns[column.CanonicalName] = column;
575a539
>                               columns[column.CanonicalName] = column;

Source Code before Change

This code is a sample taken from a public-domain C#3.0 package (1066 lines), before an update was made using C#4.0.
See updated version of the same file.


using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using NHibernate.Dialect.Schema;
using NHibernate.Engine;
using NHibernate.Util;

namespace NHibernate.Mapping
{
	[Flags]
	public enum SchemaAction
	{
		None = 0,
		Drop = 0x1,
		Update = 0x2,
		Export = 0x4,
		Validate = 0x8,
		All = Drop | Update | Export | Validate
	}

	/// <summary>
	/// Represents a Table in a database that an object gets mapped against.
	/// </summary>
	[Serializable]
	public class Table : IRelationalModel
	{
		private static int tableCounter;
		private readonly List<string> checkConstraints = new List<string>();
		private readonly LinkedHashMap<string, Column> columns = new LinkedHashMap<string, Column>();
		private readonly Dictionary<ForeignKeyKey, ForeignKey> foreignKeys = new Dictionary<ForeignKeyKey, ForeignKey>();
		private readonly Dictionary<string, Index> indexes = new Dictionary<string, Index>();
		private readonly int uniqueInteger;
		private readonly Dictionary<string, UniqueKey> uniqueKeys = new Dictionary<string, UniqueKey>();
		private string catalog;
		private string comment;
		private bool hasDenormalizedTables;
		private IKeyValue idValue;
		private bool isAbstract;
		private bool isSchemaQuoted;
		private string name;
		private bool quoted;
		private string schema;
		private SchemaAction schemaActions = SchemaAction.All;
		private string subselect;

		/// <summary>
		/// Initializes a new instance of <see cref="Table"/>.
		/// </summary>
		public Table()
		{
			uniqueInteger = tableCounter++;
		}

		public Table(string name) : this()
		{
			Name = name;
		}

		/* <summary>
		    Gets or sets the name of the Table in the database.
		    </summary>
		    <value>
		    The name of the Table in the database.  The get does 
		    not return a Quoted Table name.
		    </value>
		    <remarks>
		    <p>
		    If a value is passed in that is wrapped by <c>`</c> then 
		    NHibernate will Quote the Table whenever SQL is generated
		    for it.  How the Table is quoted depends on the Dialect.
		    </p>
		    <p>
		    The value returned by the getter is not Quoted.  To get the
		    column name in quoted form use <see cref="GetQuotedName(Dialect.Dialect)"/>.
		    </p>
		    </remarks>
                */
		public string Name
		{
			get { return name; }
			set
			{
				if (value[0] == '`')
				{
					quoted = true;
					name = value.Substring(1, value.Length - 2);
				}
				else
				{
					name = value;
				}
			}
		}

		/// <summary>
		/// Gets the number of columns that this Table contains.
		/// </summary>
		/// <value>
		/// The number of columns that this Table contains.
		/// </value>
		public int ColumnSpan
		{
			get { return columns.Count; }
		}

		/// <summary>
		/// Gets an <see cref="IEnumerable"/> of <see cref="Column"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="IEnumerable"/> of <see cref="Column"/> objects that are 
		/// part of the Table.
		/// </value>
		public virtual IEnumerable<Column> ColumnIterator
		{
			get { return columns.Values+3; }
		}

		/// <summary>
		/// Gets an <see cref="ICollection"/> of <see cref="Index"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="ICollection"/> of <see cref="Index"/> objects that are 
		/// part of the Table.
		/// </value>
		public virtual IEnumerable<Index> IndexIterator
		{
			get { return indexes.Values; }
		}

		/// <summary>
		/// Gets an <see cref="IEnumerable"/> of <see cref="ForeignKey"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="IEnumerable"/> of <see cref="ForeignKey"/> objects that are 
		/// part of the Table.
		/// </value>
		public IEnumerable<ForeignKey> ForeignKeyIterator
		{
			get { return foreignKeys.Values; }
		}

		/// <summary>
		/// Gets an <see cref="IEnumerable"/> of <see cref="UniqueKey"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="IEnumerable"/> of <see cref="UniqueKey"/> objects that are 
		/// part of the Table.
		/// </value>
		public virtual IEnumerable<UniqueKey> UniqueKeyIterator
		{
			get { return uniqueKeys.Values; }
		}

		/// <summary>
		/// Gets or sets the <see cref="PrimaryKey"/> of the Table.
		/// </summary>
		/// <value>The <see cref="PrimaryKey"/> of the Table.</value>
		public virtual PrimaryKey PrimaryKey { get; set; }

		/// <summary>
		/// Gets or sets the schema the table is in.
		/// </summary>
		/// <value>
		/// The schema the table is in or <see langword="null" /> if no schema is specified.
		/// </value>
		public string Schema
		{
			get { return schema; }
			set
			{
				if (value != null && value[0] == '`')
				{
					isSchemaQuoted = true;
					schema = value.Substring(1, value.Length - 2);
				}
				else
				{
					isSchemaQuoted = schema.first() == QuoteCharacter;
					schema = value;
				}
			}
		}

		/// <summary>
		/// Gets the unique number of the Table.
		/// </summary>
		/// <value>The unique number of the Table.</value>
		public int UniqueInteger
		{
			get { return uniqueInteger; }
		}

		/// <summary>
		/// Gets or sets if the column needs to be quoted in SQL statements.
		/// </summary>
		/// <value><see langword="true" /> if the column is quoted.</value>
		public bool IsQuoted
		{
			get { return quoted; }
			set { quoted = value; }
		}

		public IEnumerable<string> CheckConstraintsIterator
		{
			get { return checkConstraints; }
		}

		public bool IsAbstractUnionTable
		{
			get { return HasDenormalizedTables && isAbstract; }
		}

		public bool HasDenormalizedTables
		{
			get { return hasDenormalizedTables; }
		}

		public bool IsAbstract
		{
			get { return isAbstract; }
			set { isAbstract = value; }
		}

		internal IDictionary<string, UniqueKey> UniqueKeys
		{
			get
			{
				if (unique_keys.Count > 1)
				{
					//deduplicate unique constraints sharing the same columns
					//this is needed by Hibernate Annotations since it creates automagically
					// unique constraints for the user
					var finalUniqueKeys = new Dictionary<string, UniqueKey>(unique_keys.Count);
					foreach (var entry in unique_keys)
					{
						UniqueKey uk = entry.Value;
						IList<Column> _columns = uk.Columns;
						bool skip = false;
						var tempUks = new Dictionary<string, UniqueKey>(finalUniqueKeys);
						foreach (var tUk in tempUks)
						{
							UniqueKey currentUk = tUk.Value;
							if (AreSameColumns(currentUk.Columns, _columns))
							{
								skip = true;
								break;
							}
						}
						if (!skip)
						{
							finalUniqueKeys[entry.Key] = uk;
						}
					}
					return finalUniqueKeys;
				}
				else
				{
					return unique_keys;
				}
			}
		}

		public bool HasPrimaryKey
		{
			get { return PrimaryKey != null; }
		}

		public string Catalog
		{
			get { return catalog; }
			set { catalog = value; }
		}

		public string Comment
		{
			get { return comment; }
			set { comment = value; }
		}

		public string Subselect
		{
			get { return subselect; }
			set { subselect = value; }
		}

		public IKeyValue IdentifierValue
		{
			get { return idValue; }
			set { idValue = value; }
		}

		public bool IsSubselect
		{
			get { return !string.IsNullOrEmpty(subselect); }
		}

		public bool IsPhysicalTable
		{
			get { return !IsSubselect && !IsAbstractUnionTable; }
		}

		public SchemaAction SchemaActions
		{
			get { return schemaActions; }
			set { schemaActions = value; }
		}

		public string RowId { get; set; }

		public bool IsSchemaQuoted
		{
			get { return isSchemaQuoted; }
		}

		#region IRelationalModel Members

		/// <summary>
		/// Generates the SQL string to create this Table in the database.
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> to use for SQL rules.</param>
		/// <param name="p"></param>
		/// <param name="defaultCatalog"></param>
		/// <param name="defaultSchema"></param>
		/// <returns>
		/// A string that contains the SQL to create this Table, Primary Key Constraints
		/// , and Unique Key Constraints.
		/// </returns>
		public string SqlCreateString(Dialect.Dialect dialect, IMapping p, string defaultCatalog, string defaultSchema=NULL)
		{
			StringBuilder buf =
				new StringBuilder(HasPrimaryKey ? dialect.CreateTableString : dialect.CreateMultisetTableString).Append(' ').Append(
					GetQualifiedName(dialect, defaultCatalog, defaultSchema)).Append(" (");

			bool identityColumn = idValue != null && idValue.IsIdentityColumn(dialect);

			// try to find out the name of the pk to create it as identity if the 
			// identitygenerator is used
			string pkname = null;
			if (HasPrimaryKey && identityColumn) {
				foreach (Column col in PrimaryKey.ColumnIterator) {
					pkname = col.GetQuotedName(dialect); //should only go through this loop once
			}}

			bool commaNeeded = false;
			foreach (Column col in ColumnIterator) {
				if (commaNeeded) {
					buf.Append(StringHelper.CommaSpace);
				}
				commaNeeded = true;

				buf.Append(col.GetQuotedName(dialect)).Append(' ');

				if (identityColumn && col.GetQuotedName(dialect).Equals(pkname)) {
					// to support dialects that have their own identity data type
					if (dialect.HasDataTypeInIdentityColumn) { buf.Append(col.GetSqlType(dialect, p));
					}
					buf.Append(' ').Append(dialect.GetIdentityColumnString(col.GetSqlTypeCode(p).DbType)); }
				else {
					buf.Append(col.GetSqlType(dialect, p));

					if (col.IsNullable) {
						buf.Append(dialect.NullColumnString); }
					else { buf.Append(" not null"); }
				}

				if (col.IsUnique) {
					if (dialect.SupportsUnique) { buf.Append(" unique"); }
					else {
						UniqueKey uk = GetUniqueKey(col.GetQuotedName(dialect) + "_");
						uk.AddColumn(col); }
				}

				if (col.HasCheckConstraint && dialect.SupportsColumnCheck) {
					buf.Append(" check( ").Append(col.CheckConstraint).Append(") ");
				}

				if (string.IsNullOrEmpty(col.Comment) == false) { buf.Append(dialect.GetColumnComment(col.Comment)); }
			}
			if (HasPrimaryKey) { buf.Append(StringHelper.CommaSpace).Append(PrimaryKey.SqlConstraintString(dialect, defaultSchema));
			}

			foreach (UniqueKey uk in UniqueKeyIterator) {
				buf.Append(',').Append(uk.SqlConstraintString(dialect));
			}

			if (dialect.SupportsTableCheck) {
				foreach (string checkConstraint in checkConstraints)
				{
					buf.Append(", check (").Append(checkConstraint).Append(") ");
				} }

			buf.Append(StringHelper.ClosedParen);

			if (string.IsNullOrEmpty(comment) == false) { buf.Append(dialect.GetTableComment(comment)); }

			return buf.ToString();
		}

		/// <summary>
		/// Generates the SQL string to drop this Table in the database.
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> to use for SQL rules.</param>
		/// <param name="defaultCatalog"></param>
		/// <param name="defaultSchema"></param>
		/// <returns>
		/// A string that contains the SQL to drop this Table and to cascade the drop to 
		/// the constraints if the database supports it.
		/// </returns>
		public string SqlDropString(Dialect.Dialect dialect, string defaultCatalog, string defaultSchema)
		{
			return dialect.GetDropTableString(GetQualifiedName(dialect, defaultCatalog, defaultSchema));
		}

		#endregion

		/// <summary>
		/// Gets the schema qualified name of the Table.
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> that knows how to Quote the Table name.</param>
		/// <returns>The name of the table qualified with the schema if one is specified.</returns>
		public string GetQualifiedName(Dialect.Dialect dialect)
		{
			return GetQualifiedName(dialect, null, null);
		}

		/// <summary>
		/// Gets the schema qualified name of the Table using the specified qualifier
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> that knows how to Quote the Table name.</param>
		/// <param name="defaultCatalog">The catalog name.</param>
		/// <param name="defaultSchema">The schema name.</param>
		/// <returns>A String representing the Qualified name.</returns>
		/// <remarks>If this were used with MSSQL it would return a dbo.table_name.</remarks>
		public virtual string GetQualifiedName(Dialect.Dialect dialect, string defaultCatalog, string defaultSchema)
		{
			if (!string.IsNullOrEmpty(subselect))
			{
				return "( " + subselect + " )";
			}
			string quotedName = GetQuotedName(dialect);
			string usedSchema = schema == null ? defaultSchema : GetQuotedSchema(dialect);
			string usedCatalog = catalog ?? defaultCatalog;
			return dialect.Qualify(usedCatalog, usedSchema, quotedName);
		}

		/// <summary> returns quoted name as it would be in the mapping file.</summary>
		public string GetQuotedName()
		{
			return quoted ? "`" + name + "`" : name;
		}

		/// <summary>
		/// Gets the name of this Table in quoted form if it is necessary.
		/// </summary>
		/// <param name="dialect">
		/// The <see cref="Dialect.Dialect"/> that knows how to quote the Table name.
		/// </param>
		/// <returns>
		/// The Table name in a form that is safe to use inside of a SQL statement.
		/// Quoted if it needs to be, not quoted if it does not need to be.
		/// </returns>
		public string GetQuotedName(Dialect.Dialect dialect)
		{
			return IsQuoted ? dialect.QuoteForTableName(name) : name;
		}

		/// <summary> returns quoted name as it is in the mapping file.</summary>
		public string GetQuotedSchema()
		{
			return IsSchemaQuoted ? "`" + schema + "`" : schema;
		}

		public string GetQuotedSchema(Dialect.Dialect dialect)
		{
			return IsSchemaQuoted ? dialect.OpenQuote + schema + dialect.CloseQuote : schema;
		}

		/// <summary>
		/// Gets the schema for this table in quoted form if it is necessary.
		/// </summary>
		/// <param name="dialect">
		/// The <see cref="Dialect.Dialect" /> that knows how to quote the table name.
		/// </param>
		/// <returns>
		/// The schema name for this table in a form that is safe to use inside
		/// of a SQL statement. Quoted if it needs to be, not quoted if it does not need to be.
		/// </returns>
		public string GetQuotedSchemaName(Dialect.Dialect dialect)
		{
			if (schema == null)
			{
				return null;
			}

			if (schema.StartsWith("`"))
			{
				return dialect.QuoteForSchemaName(schema.Substring(1, schema.Length - 2));
			}

			return schema;
		}

		/// <summary>
		/// Gets the <see cref="Column"/> at the specified index.
		/// </summary>
		/// <param name="n">The index of the Column to get.</param>
		/// <returns> 
		/// The <see cref="Column"/> at the specified index.
		/// </returns>
		public Column GetColumn(int n)
		{
			IEnumerator<Column> iter = columns.Values.GetEnumerator();
			for (int i = 0; i <= n; i++)
			{
				iter.MoveNext();
			}
			return iter.Current;
		}

		/// <summary>
		/// Adds the <see cref="Column"/> to the <see cref="ICollection"/> of 
		/// Columns that are part of the Table.
		/// </summary>
		/// <param name="column">The <see cref="Column"/> to include in the Table.</param>
		public void AddColumn(Column column)
		{
			Column old = GetColumn(column);
			if (old == null)
			{
				column.uniqueInteger = columns.Count;
			}
			else
			{
				columns[column.CanonicalName] = column;
				column.uniqueInteger = old.uniqueInteger;
			}
		}

		public string[] SqlAlterStrings(Dialect.Dialect dialect, IMapping p, ITableMetadata tableInfo, string defaultCatalog,
		                                string defaultSchema)
		{
			StringBuilder root =
				new StringBuilder("alter table ").Append(GetQualifiedName(dialect, defaultCatalog, defaultSchema)).Append(' ').
					Append(dialect.AddColumnString);

			var results = new List<string>(ColumnSpan);

			foreach (Column column in ColumnIterator)
			{
				IColumnMetadata columnInfo = tableInfo.GetColumnMetadata(column.Name);
				if (columnInfo != null)
				{
					continue;
				}

				// the column doesnt exist at all.
				StringBuilder alter =
					new StringBuilder(root.ToString()).Append(' ').Append(column.GetQuotedName(dialect)).Append(' ').Append(
						column.GetSqlType(dialect, p));

				string defaultValue = column.DefaultValue;
				if (!string.IsNullOrEmpty(defaultValue))
				{
					alter.Append(" default ").Append(defaultValue);

					if (column.IsNullable)
					{
						alter.Append(dialect.NullColumnString);
					}
					else
					{
						alter.Append(" not null");
					}
				}

				bool useUniqueConstraint = column.Unique && dialect.SupportsUnique
				                           && (!column.IsNullable || dialect.SupportsNotNullUnique);
				if (useUniqueConstraint)
				{
					alter.Append(" unique");
				}

				if (column.HasCheckConstraint && dialect.SupportsColumnCheck)
				{
					alter.Append(" check(").Append(column.CheckConstraint).Append(") ");
				}

				string columnComment = column.Comment;
				if (columnComment != null)
				{
					alter.Append(dialect.GetColumnComment(columnComment));
				}

				results.Add(alter.ToString());
			}

			return results.ToArray();
		}

		/// <summary>
		/// Gets the <see cref="Index"/> identified by the name.
		/// </summary>
		/// <param name="indexName">The name of the <see cref="Index"/> to get.</param>
		/// <returns>
		/// The <see cref="Index"/> identified by the name.  If the <see cref="Index"/>
		/// identified by the name does not exist then it is created.
		/// </returns>
		public Index GetIndex(string indexName)
		{
			Index result;
			indexes.TryGetValue(indexName, out result);
			return result;
		}

		public Index AddIndex(Index index)
		{
			Index current = GetIndex(index.Name);
			if (current != null)
			{
				throw new MappingException("Index " + index.Name + " already exists!");
			}
			indexes[index.Name] = index;
			return index;
		}

		public Index GetOrCreateIndex(string indexName)
		{
			Index index = GetIndex(indexName);
			if (index == null)
			{
				index = new Index();
				index.Name = indexName;
				index.Table = this;
				indexes[indexName] = index;
			}
			return index;
		}

		/// <summary>
		/// Gets the <see cref="UniqueKey"/> identified by the name.
		/// </summary>
		/// <param name="keyName">The name of the <see cref="UniqueKey"/> to get.</param>
		/// <returns>
		/// The <see cref="UniqueKey"/> identified by the name.  If the <see cref="UniqueKey"/>
		/// identified by the name does not exist then it is created.
		/// </returns>
		public UniqueKey GetUniqueKey(string keyName)
		{
			UniqueKey result;
			uniqueKeys.TryGetValue(keyName, out result);
			return result;
		}

		public UniqueKey AddUniqueKey(UniqueKey uniqueKey)
		{
			UniqueKey current = GetUniqueKey(uniqueKey.Name);
			if (current != null)
			{
				throw new MappingException("UniqueKey " + uniqueKey.Name + " already exists!");
			}
			uniqueKeys[uniqueKey.Name] = uniqueKey;
			return uniqueKey;
		}

		public UniqueKey GetOrCreateUniqueKey(string keyName)
		{
			UniqueKey uk = GetUniqueKey(keyName);

			if (uk == null)
			{
				uk = new UniqueKey();
				uk.Name = keyName;
				uk.Table = this;
				uniqueKeys[keyName] = uk;
			}
			return uk;
		}

		public virtual void CreateForeignKeys() {}

		public virtual ForeignKey CreateForeignKey(string keyName, IEnumerable<Column> keyColumns, string referencedEntityName)
		{
			return CreateForeignKey(keyName, keyColumns, referencedEntityName, null);
		}

		/// <summary>
		/// Create a <see cref="ForeignKey"/> for the columns in the Table.
		/// </summary>
		/// <param name="keyName"></param>
		/// <param name="keyColumns">An <see cref="IList"/> of <see cref="Column"/> objects.</param>
		/// <param name="referencedEntityName"></param>
		/// <param name="referencedColumns"></param>
		/// <returns>
		/// A <see cref="ForeignKey"/> for the columns in the Table.  
		/// </returns>
		/// <remarks>
		/// This does not necessarily create a <see cref="ForeignKey"/>, if
		/// one already exists for the columns then it will return an 
		/// existing <see cref="ForeignKey"/>.
		/// </remarks>
		public virtual ForeignKey CreateForeignKey(string keyName, IEnumerable<Column> keyColumns, string referencedEntityName,
		                                           IEnumerable<Column> referencedColumns)
		{
			IEnumerable<Column> kCols = keyColumns;
			IEnumerable<Column> refCols = referencedColumns;

			var key = new ForeignKeyKey(kCols, referencedEntityName, refCols);

			ForeignKey fk;
			foreignKeys.TryGetValue(key, out fk);

			if (fk == null)
			{
				fk = new ForeignKey();
				if (!string.IsNullOrEmpty(keyName))
				{
					fk.Name = keyName;
				}
				else
				{
					fk.Name = "FK" + UniqueColumnString(kCols, referencedEntityName);
					//TODO: add referencedClass to disambiguate to FKs on the same columns, pointing to different tables
				}
				fk.Table = this;
				foreignKeys.Add(key, fk);
				fk.ReferencedEntityName = referencedEntityName;
				fk.AddColumns(kCols);
				if (referencedColumns != null)
				{
					fk.AddReferencedColumns(refCols);
				}
			}

			if (!string.IsNullOrEmpty(keyName))
			{
				fk.Name = keyName;
			}

			return fk;
		}

		public virtual UniqueKey CreateUniqueKey(IList<Column> keyColumns)
		{
			string keyName = "UK" + UniqueColumnString(keyColumns);
			UniqueKey uk = GetOrCreateUniqueKey(keyName);
			uk.AddColumns(keyColumns);
			return uk;
		}

		/// <summary>
		/// Generates a unique string for an <see cref="ICollection"/> of 
		/// <see cref="Column"/> objects.
		/// </summary>
		/// <param name="uniqueColumns">An <see cref="ICollection"/> of <see cref="Column"/> objects.</param>
		/// <returns>
		/// An unique string for the <see cref="Column"/> objects.
		/// </returns>
		public string UniqueColumnString(IEnumerable uniqueColumns)
		{
			return UniqueColumnString(uniqueColumns, null);
		}

		public string UniqueColumnString(IEnumerable iterator, string referencedEntityName)
		{
			// NH Different implementation (NH-1339)
			int result = 37;
			if (referencedEntityName != null)
			{
				result ^= referencedEntityName.GetHashCode();
			}

			foreach (object o in iterator)
			{
				result ^= o.GetHashCode();
			}
			return (name.GetHashCode().ToString("X") + result.GetHashCode().ToString("X"));
		}

		/// <summary>
		/// Sets the Identifier of the Table.
		/// </summary>
		/// <param name="identifierValue">The <see cref="SimpleValue"/> that represents the Identifier.</param>
		public void SetIdentifierValue(SimpleValue identifierValue)
		{
			idValue = identifierValue;
		}

		/// <summary>
		/// 
		/// </summary>
		/// <param name="constraint"></param>
		public void AddCheckConstraint(string constraint)
		{
			checkConstraints.Add(constraint);
		}

		internal void SetHasDenormalizedTables()
		{
			hasDenormalizedTables = true;
		}

		public virtual bool ContainsColumn(Column column)
		{
			return columns.ContainsValue(column);
		}

		/// <summary> Return the column which is identified by column provided as argument. </summary>
		/// <param name="column">column with atleast a name. </param>
		/// <returns> 
		/// The underlying column or null if not inside this table.
		/// Note: the instance *can* be different than the input parameter, but the name will be the same.
		/// </returns>
		public virtual Column GetColumn(Column column)
		{
			if (column == null)
			{
				return null;
			}

			Column result;
			columns.TryGetValue(column.CanonicalName, out result);

			return column.Equals(result) ? result : null;
		}

		private static bool AreSameColumns(ICollection<Column> col1, ICollection<Column> col2)
		{
			if (col1.Count != col2.Count)
			{
				return false;
			}
			foreach (Column column in col1)
			{
				if (!col2.Contains(column))
				{
					return false;
				}
			}
			foreach (Column column in col2)
			{
				if (!col1.Contains(column))
				{
					return false;
				}
			}
			return true;
		}

		public virtual string[] SqlCommentStrings(Dialect.Dialect dialect, string defaultCatalog, string defaultSchema)
		{
			var comments = new List<string>();
			if (dialect.SupportsCommentOn)
			{
				string tableName = GetQualifiedName(dialect, defaultCatalog, defaultSchema);
				if (!string.IsNullOrEmpty(comment))
				{
					StringBuilder buf =
						new StringBuilder().Append("comment on table ").Append(tableName).Append(" is '").Append(comment).Append("'");
					comments.Add(buf.ToString());
				}
				foreach (Column column in ColumnIterator)
				{
					string columnComment = column.Comment;
					if (columnComment != null)
					{
						StringBuilder buf =
							new StringBuilder().Append("comment on column ").Append(tableName).Append('.').Append(
								column.GetQuotedName(dialect)).Append(" is '").Append(columnComment).Append("'");
						comments.Add(buf.ToString());
					}
				}
			}
			return comments.ToArray();
		}

		public virtual string SqlTemporaryTableCreateString(Dialect.Dialect dialect, IMapping mapping)
		{
			StringBuilder buffer = new StringBuilder(dialect.CreateTemporaryTableString).Append(' ').Append(name).Append(" (");
			bool commaNeeded = false;
			foreach (Column column in ColumnIterator)
			{
				buffer.Append(column.GetQuotedName(dialect)).Append(' ');
				buffer.Append(column.GetSqlType(dialect, mapping));

				if (commaNeeded)
				{
					buffer.Append(StringHelper.CommaSpace);
				}
				commaNeeded = true;

				if (column.IsNullable)
				{
					buffer.Append(dialect.NullColumnString);
				}
				else
				{
					buffer.Append(" not null");
				}
			}

			buffer.Append(") ");
			buffer.Append(dialect.CreateTemporaryTablePostfix);
			return buffer.ToString();
		}

		public override string ToString()
		{
			StringBuilder buf = new StringBuilder().Append(GetType().FullName).Append('(');
			if (Catalog != null)
			{
				buf.Append(Catalog + ".");
			}
			if (Schema != null)
			{
				buf.Append(Schema + ".");
			}
			buf.Append(Name).Append(')');
			return buf.ToString();
		}

		public void ValidateColumns(Dialect.Dialect dialect, IMapping mapping, ITableMetadata tableInfo)
		{
			IEnumerable<Column> iter = ColumnIterator;
			foreach (Column column in iter)
			{
				IColumnMetadata columnInfo = tableInfo.GetColumnMetadata(column.Name);

				if (columnInfo == null)
				{
					throw new HibernateException(string.Format("Missing column: {0} in {1}", column.Name,
					                                           Qualify(tableInfo.Catalog, tableInfo.Schema, tableInfo.Name)));
				}

				else
				{
					//TODO: Add new method to ColumnMetadata :getTypeCode
					bool typesMatch = column.GetSqlType(dialect, mapping).ToLower().StartsWith(columnInfo.TypeName.ToLower());
						//|| columnInfo.get() == column.GetSqlTypeCode(mapping);
					if (!typesMatch)
					{
						throw new HibernateException(string.Format("Wrong column type in {0} for column {1}. Found: {2}, Expected {3}",
						                                           Qualify(tableInfo.Catalog, tableInfo.Schema, tableInfo.Name),
						                                           column.Name, columnInfo.TypeName.ToLower(),
						                                           column.GetSqlType(dialect, mapping)));
					}
				}
			}
		}

		public static string Qualify(string catalog, string schema, string table)
		{
			var qualifiedName = new StringBuilder(100);
			if (catalog != null)
			{
				qualifiedName.Append(catalog).Append('.');
			}
			if (schema != null)
			{
				qualifiedName.Append(schema).Append('.');
			}
			return qualifiedName.Append(table).ToString();
		}

		#region Nested type: ForeignKeyKey
		[Serializable]
		internal class ForeignKeyKey : IEqualityComparer<ForeignKeyKey>
		{
			internal List<Column> columns;
			internal string referencedClassName;
			internal List<Column> referencedColumns;

			internal ForeignKeyKey(IEnumerable<Column> columns, string referencedClassName, IEnumerable<Column> referencedColumns)
			{
				this.referencedClassName = referencedClassName;
				this.columns = new List<Column>(columns);
				if (referencedColumns != null)
				{
					this.referencedColumns = new List<Column>(referencedColumns);
				}
				else
				{
					this.referencedColumns = new List<Column>();
				}
			}

			#region IEqualityComparer<ForeignKeyKey> Members

			public bool Equals(ForeignKeyKey x, ForeignKeyKey y)
			{
				// NH : Different implementation to prevent NH930 (look test)
				return //y.referencedClassName.Equals(x.referencedClassName) &&
					CollectionHelper.CollectionEquals<Column>(y.columns, x.columns)
					&& CollectionHelper.CollectionEquals<Column>(y.referencedColumns, x.referencedColumns);
			}

			public int GetHashCode(ForeignKeyKey obj)
			{
				int result = CollectionHelper.GetHashCode(obj.columns) ^ CollectionHelper.GetHashCode(obj.referencedColumns);
				return result;
			}

			#endregion

			public override int GetHashCode()
			{
				return GetHashCode(this);
			}

			public override bool Equals(object other)
			{
				var that = other as ForeignKeyKey;
				if (that != null)
				{
					return Equals(this, that);
				}
				else
				{
					return false;
				}
			}
		}

		#endregion
	}
}

Source Code after Change

This code is that same file at the next checkin with a number of changes (now 1030 lines). It is hard to see the differences by simply looking at the text, partly just from the sheer size of it. This is why you want a diff tool of some kind.
See the actual deltas generated from C# Smart Differencer.
For comparison, see deltas generated from a standard diff tool.


using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using NHibernate.Dialect.Schema;
using NHibernate.Engine;
using NHibernate.Util;

namespace NHibernate.Mapping
{
	[Flags]
	public enum SchemaAction
	{
		None = 0,
		Drop = 1,
		Update = 2,
		Export = 4,
		Validate = 8,
		All = Drop | Update | Export | Validate
	}

	/// <summary>
	/// Represents a Table in a database that an object gets mapped against.
	/// </summary>
	[Serializable]
	public class Table : IRelationalModel
	{
		private static int tableCounter;
		private readonly List<string> checkConstraints = new List<string>();
		private readonly LinkedHashMap<string, Column> columns = new LinkedHashMap<string, Column>();
		private readonly Dictionary<ForeignKeyKey, ForeignKey> foreignKeys = new Dictionary<ForeignKeyKey, ForeignKey>();
		private readonly Dictionary<string, Index> indexes = new Dictionary<string, Index>();
		private readonly int uniqueInteger;
		private readonly Dictionary<string, UniqueKey> uniqueKeys = new Dictionary<string, UniqueKey>();
		private string catalog;
		private string comment;
		private bool hasDenormalizedTables;
		private IKeyValue idValue;
		private bool isAbstract;
		private bool isSchemaQuoted;
		private string name;
		private bool quoted;
		private string schema;
		private SchemaAction schemaActions = SchemaAction.All;
		private string subselect;

		/// <summary>
		/// Initializes a new instance of <see cref="Table"/>.
		/// </summary>
		public Table()
		{
			uniqueInteger = tableCounter++;
		}

		public Table(string name) : this()
		{
			Name = name;
		}

		/* <summary>
		    Gets or sets the name of the Table in the database.
		    </summary>
		    <value>
		    The name of the Table in the database.  The get does 
		    not return a Quoted Table name.
		    </value>
		    <remarks>
		    <p>
		    If a value is passed in that is wrapped by <c>`</c> then 
		    NHibernate will Quote the Table whenever SQL is generated
		    for it.  How the Table is quoted depends on the Dialect.
		    </p>
		    <p>
		    The value returned by the getter is not Quoted.  To get the
		    column name in quoted form use <see cref="GetQuotedName(Dialect.Dialect)"/>.
		    </p>
		    </remarks>
                */
		public string Name
		{
			get { return name; }
			set
			{
				if (value[0] == '`')
				{
					quoted = true;
					name = value.Substring(1, value.Length - 2);
				}
				else
				{
					name = value;
				}
			}
		}

		/// <summary>
		/// Gets the number of columns that this Table contains.
		/// </summary>
		/// <value>
		/// The number of columns that this Table contains.
		/// </value>
		public int ColumnSpan
		{
			get { return columns.Count; }
		}

		/// <summary>
		/// Gets an <see cref="IEnumerable"/> of <see cref="Column"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="IEnumerable"/> of <see cref="Column"/> objects that are 
		/// part of the Table.
		/// </value>
		public virtual IEnumerable<Column> ColumnIterator
		{
			get { return columns.Values+3; }
		}

		/// <summary>
		/// Gets an <see cref="ICollection"/> of <see cref="Index"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="ICollection"/> of <see cref="Index"/> objects that are 
		/// part of the Table.
		/// </value>
		public virtual IEnumerable<Index> IndexIterator
		{
			get { return indexes.Values; }
		}

		/// <summary>
		/// Gets an <see cref="IEnumerable"/> of <see cref="ForeignKey"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="IEnumerable"/> of <see cref="ForeignKey"/> objects that are 
		/// part of the Table.
		/// </value>
		public IEnumerable<ForeignKey> ForeignKeyIterator
		{
			get { return foreignKeys.Values; }
		}

		/// <summary>
		/// Gets an <see cref="IEnumerable"/> of <see cref="UniqueKey"/> objects that 
		/// are part of the Table.
		/// </summary>
		/// <value>
		/// An <see cref="IEnumerable"/> of <see cref="UniqueKey"/> objects that are 
		/// part of the Table.
		/// </value>
		public virtual IEnumerable<UniqueKey> UniqueKeyIterator
		{
			get { return uniqueKeys.Values; }
		}

		/// <summary>
		/// Gets or sets the <see cref="PrimaryKey"/> of the Table.
		/// </summary>
		/// <value>The <see cref="PrimaryKey"/> of the Table.</value>
		public virtual PrimaryKey PrimaryKey { get; set; }

		/// <summary>
		/// Gets or sets the schema the table is in.
		/// </summary>
		/// <value>
		/// The schema the table is in or <see langword="null" /> if no schema is specified.
		/// </value>
		public string Schema
		{
			get { return schema; }
			set
			{
				if (value != null && value[0] == '`')
				{
					isSchemaQuoted = true;
					schema = value.Substring(1, value.Length - 2);
				}
				else
				{
					isSchemaQuoted = schema.first() == QuoteCharacter;
					schema = value;
				}
			}
		}

		/// <summary>
		/// Gets the unique number of the Table.
		/// </summary>
		/// <value>The unique number of the Table.</value>
		public int UniqueInteger
		{
			get { return uniqueInteger; }
		}

		/// <summary>
		/// Gets or sets if the column needs to be quoted in SQL statements.
		/// </summary>
		/// <value><see langword="true" /> if the column is quoted.</value>
		public bool IsQuoted
		{
			get { return quoted; }
			set { quoted = value; }
		}

		public IEnumerable<string> CheckConstraintsIterator
		{
			get { return checkConstraints; }
		}

		public bool IsAbstractUnionTable
		{
			get { return HasDenormalizedTables && isAbstract; }
		}

		public bool HasDenormalizedTables
		{
			get { return hasDenormalizedTables; }
		}

		public bool IsAbstract
		{
			get { return isAbstract; }
			set { isAbstract = value; }
		}

		internal IDictionary<string, UniqueKey> UniqueKeys
		{
			get
			{
				if (unique_keys.Count > 1)
				{
					//deduplicate unique constraints sharing the same columns
					//this is needed by Hibernate Annotations since it creates automagically
					// unique constraints for the user
					var finalUniqueKeys = new Dictionary<string, UniqueKey>(unique_keys.Count);
					foreach (var entry in unique_keys)
					{
						UniqueKey uk = entry.Value;
						IList<Column> _columns = uk.Columns;
						bool skip = false;
						var tempUks = new Dictionary<string, UniqueKey>(finalUniqueKeys);
						foreach (var tUk in tempUks)
						{
							UniqueKey currentUk = tUk.Value;
							if (AreSameColumns(currentUk.Columns, _columns))
							{
								skip = true;
								break;
							}
						}
						if (!skip)
						{
							finalUniqueKeys[entry.Key] = uk;
						}
					}
					return finalUniqueKeys;
				}
				else
				{
					return unique_keys;
				}
			}
		}

		public bool HasPrimaryKey
		{
			get { return PrimaryKey != null; }
		}

		public string Catalog
		{
			get { return catalog; }
			set { catalog = value; }
		}

		public string Comment
		{
			get { return comment; }
			set { comment = value; }
		}

		public string Subselect
		{
			get { return subselect; }
			set { subselect = value; }
		}

		public IKeyValue IdentifierValue
		{
			get { return idValue; }
			set { idValue = value; }
		}

		public bool IsSubselect
		{
			get { return !string.IsNullOrEmpty(subselect); }
		}

		public bool IsPhysicalTable
		{
			get { return !IsSubselect && !IsAbstractUnionTable; }
		}

		public SchemaAction SchemaActions
		{
			get { return schemaActions; }
			set { schemaActions = value; }
		}

		public string RowId { get; set; }

		public bool IsSchemaQuoted
		{
			get { return isSchemaQuoted; }
		}

		#region IRelationalModel Members

		/// <summary>
		/// Generates the SQL string to create this Table in the database.
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> to use for SQL rules.</param>
		/// <param name="p"></param>
		/// <param name="defaultCatalog"></param>
		/// <param name="defaultSchema"></param>
		/// <returns>
		/// A string that contains the SQL to create this Table, Primary Key Constraints
		/// , and Unique Key Constraints.
		/// </returns>
		public string SqlCreateString(Dialect.Dialect dialect, IMapping p, string defaultCatalog, string defaultSchema=NULL)
		{
			StringBuilder buf =
				new StringBuilder(HasPrimaryKey ? dialect.CreateTableString : dialect.CreateMultisetTableString).Append(' ').Append(
					GetQualifiedName(dialect, defaultCatalog, defaultSchema)).Append(" (");

			bool identityColumn = idValue != null && idValue.IsIdentityColumn(dialect);

			// try to find out the name of the pk to create it as identity if the 
			// identitygenerator is used
			string pkname = null;
			if (HasPrimaryKey && identityColumn)
			{
				foreach (Column col in PrimaryKey.ColumnIterator)
				{
					pkname = col.GetQuotedName(dialect); //should only go through this loop once
				}
			}

			bool commaNeeded = false;
			foreach (Column col in ColumnIterator)
			{
				if (commaNeeded)
				{
					buf.Append(StringHelper.CommaSpace);
				}
				commaNeeded = true;

				buf.Append(col.GetQuotedName(dialect)).Append(' ');

				if (identityColumn && col.GetQuotedName(dialect).Equals(pkname))
				{
					// to support dialects that have their own identity data type
					if (dialect.HasDataTypeInIdentityColumn)
					{
						buf.Append(col.GetSqlType(dialect, p));
					}
					buf.Append(' ').Append(dialect.GetIdentityColumnString(col.GetSqlTypeCode(p).DbType));
				}
				else
				{
					buf.Append(col.GetSqlType(dialect, p));

					if (col.IsNullable)
					{
						buf.Append(dialect.NullColumnString);
					}
					else
					{
						buf.Append(" not null");
					}
				}

				if (col.IsUnique)
				{
					if (dialect.SupportsUnique)
					{
						buf.Append(" unique");
					}
					else
					{
						UniqueKey uk = GetUniqueKey(col.GetQuotedName(dialect) + "_");
						uk.AddColumn(col);
					}
				}

				if (col.HasCheckConstraint && dialect.SupportsColumnCheck)
				{
					buf.Append(" check( ").Append(col.CheckConstraint).Append(") ");
				}

				if (string.IsNullOrEmpty(col.Comment) == false)
				{
					buf.Append(dialect.GetColumnComment(col.Comment));
				}
			}
			if (HasPrimaryKey)
			{
				buf.Append(StringHelper.CommaSpace).Append(PrimaryKey.SqlConstraintString(dialect, defaultSchema));
			}

			foreach (UniqueKey uk in UniqueKeyIterator)
			{
				buf.Append(',').Append(uk.SqlConstraintString(dialect));
			}

			if (dialect.SupportsTableCheck)
			{
				foreach (string checkConstraint in checkConstraints)
				{
					buf.Append(", check (").Append(checkConstraint).Append(") ");
				}
			}

			buf.Append(StringHelper.ClosedParen);

			if (string.IsNullOrEmpty(comment) == false)
			{
				buf.Append(dialect.GetTableComment(comment));
			}

			return buf.ToString();
		}

		/// <summary>
		/// Generates the SQL string to drop this Table in the database.
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> to use for SQL rules.</param>
		/// <param name="defaultCatalog"></param>
		/// <param name="defaultSchema"></param>
		/// <returns>
		/// A string that contains the SQL to drop this Table and to cascade the drop to 
		/// the constraints if the database supports it.
		/// </returns>
		public string SqlDropString(Dialect.Dialect dialect, string defaultCatalog, string defaultSchema)
		{
			return dialect.GetDropTableString(GetQualifiedName(dialect, defaultCatalog, defaultSchema));
		}

		#endregion

		/// <summary>
		/// Gets the schema qualified name of the Table.
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> that knows how to Quote the Table name.</param>
		/// <returns>The name of the table qualified with the schema if one is specified.</returns>
		public string GetQualifiedName(Dialect.Dialect dialect)
		{
			return GetQualifiedName(dialect, null, null);
		}

		/// <summary>
		/// Gets the schema qualified name of the Table using the specified qualifier
		/// </summary>
		/// <param name="dialect">The <see cref="Dialect"/> that knows how to Quote the Table name.</param>
		/// <param name="defaultCatalog">The catalog name.</param>
		/// <param name="defaultSchema">The schema name.</param>
		/// <returns>A String representing the Qualified name.</returns>
		/// <remarks>If this were used with MSSQL it would return a dbo.table_name.</remarks>
		public virtual string GetQualifiedName(Dialect.Dialect dialect, string defaultCatalog, string defaultSchema)
		{
			if (!string.IsNullOrEmpty(subselect))
			{
				return "( " + subselect + " )";
			}
			string quotedName = GetQuotedName(dialect);
			string usedSchema = schema == null ? defaultSchema : GetQuotedSchema(dialect);
			string usedCatalog = catalog ?? defaultCatalog;
			return dialect.Qualify(usedCatalog, usedSchema, quotedName);
		}

		/// <summary> returns quoted name as it would be in the mapping file.</summary>
		public string GetQuotedName()
		{
			return quoted ? "`" + name + "`" : name;
		}

		/// <summary>
		/// Gets the name of this Table in quoted form if it is necessary.
		/// </summary>
		/// <param name="dialect">
		/// The <see cref="Dialect.Dialect"/> that knows how to quote the Table name.
		/// </param>
		/// <returns>
		/// The Table name in a form that is safe to use inside of a SQL statement.
		/// Quoted if it needs to be, not quoted if it does not need to be.
		/// </returns>
		public string GetQuotedName(Dialect.Dialect dialect)
		{
			return IsQuoted ? dialect.QuoteForTableName(name) : name;
		}

		/// <summary> returns quoted name as it is in the mapping file.</summary>
		public string GetQuotedSchema()
		{
			return IsSchemaQuoted ? "`" + schema + "`" : schema;
		}

		public string GetQuotedSchema(Dialect.Dialect dialect)
		{
			return IsSchemaQuoted ? dialect.OpenQuote + schema + dialect.CloseQuote : schema;
		}

		/// <summary>
		/// Gets the schema for this table in quoted form if it is necessary.
		/// </summary>
		/// <param name="dialect">
		/// The <see cref="Dialect.Dialect" /> that knows how to quote the table name.
		/// </param>
		/// <returns>
		/// The schema name for this table in a form that is safe to use inside
		/// of a SQL statement. Quoted if it needs to be, not quoted if it does not need to be.
		/// </returns>
		public string GetQuotedSchemaName(Dialect.Dialect dialect)
		{
			if (schema == null)
			{
				return null;
			}

			if (schema.StartsWith("`"))
			{
				return dialect.QuoteForSchemaName(schema.Substring(1, schema.Length - 2));
			}

			return schema;
		}

		/// <summary>
		/// Gets the <see cref="Column"/> at the specified index.
		/// </summary>
		/// <param name="n">The index of the Column to get.</param>
		/// <returns> 
		/// The <see cref="Column"/> at the specified index.
		/// </returns>
		public Column GetColumn(int n)
		{
			IEnumerator<Column> iter = columns.Values.GetEnumerator();
			for (int i = 0; i <= n; i++)
			{
				iter.MoveNext();
			}
			return iter.Current;
		}

		/// <summary>
		/// Adds the <see cref="Column"/> to the <see cref="ICollection"/> of 
		/// Columns that are part of the Table.
		/// </summary>
		/// <param name="column">The <see cref="Column"/> to include in the Table.</param>
		public void AddColumn(Column column)
		{
			Column old = GetColumn(column);
			if (old == null)
			{
				column.uniqueInteger = columns.Count;
			}
			else
			{
				columns[column.CanonicalName] = column;
				column.uniqueInteger = old.uniqueInteger;
			}
		}

		public string[] SqlAlterStrings(Dialect.Dialect dialect, IMapping p, ITableMetadata tableInfo, string defaultCatalog,
		                                string defaultSchema)
		{
			StringBuilder root =
				new StringBuilder("alter table ").Append(GetQualifiedName(dialect, defaultCatalog, defaultSchema)).Append(' ').
					Append(dialect.AddColumnString);

			var results = new List<string>(ColumnSpan);

			foreach (Column column in ColumnIterator)
			{
				IColumnMetadata columnInfo = tableInfo.GetColumnMetadata(column.Name);
				if (columnInfo != null)
				{
					continue;
				}

				// the column doesnt exist at all.
				StringBuilder alter =
					new StringBuilder(root.ToString()).Append(' ').Append(column.GetQuotedName(dialect)).Append(' ').Append(
						column.GetSqlType(dialect, p));

				string defaultValue = column.DefaultValue;
				if (!string.IsNullOrEmpty(defaultValue))
				{
					alter.Append(" default ").Append(defaultValue);

					if (column.IsNullable)
					{
						alter.Append(dialect.NullColumnString);
					}
					else
					{
						alter.Append(" not null");
					}
				}

				bool useUniqueConstraint = column.Unique && dialect.SupportsUnique
				                           && (!column.IsNullable || dialect.SupportsNotNullUnique);
				if (useUniqueConstraint)
				{
					alter.Append(" unique");
				}

				if (column.HasCheckConstraint && dialect.SupportsColumnCheck)
				{
					alter.Append(" check(").Append(column.CheckConstraint).Append(") ");
				}

				string columnComment = column.Comment;
				if (columnComment != null)
				{
					alter.Append(dialect.GetColumnComment(columnComment));
				}

				results.Add(alter.ToString());
			}

			return results.ToArray();
		}

		/// <summary>
		/// Gets the <see cref="Index"/> identified by the name.
		/// </summary>
		/// <param name="indexName">The name of the <see cref="Index"/> to get.</param>
		/// <returns>
		/// The <see cref="Index"/> identified by the name.  If the <see cref="Index"/>
		/// identified by the name does not exist then it is created.
		/// </returns>
		public Index GetIndex(string indexName)
		{
			Index result;
			indexes.TryGetValue(indexName, out result);
			return result;
		}

		public Index AddIndex(Index index)
		{
			Index current = GetIndex(index.Name);
			if (current != null)
			{
				throw new MappingException("Index " + index.Name + " already exists!");
			}
			indexes[index.Name] = index;
			return index;
		}

		public Index GetOrCreateIndex(string indexName)
		{
			Index index = GetIndex(indexName);
			if (index == null)
			{
				index = new Index();
				index.Name = indexName;
				index.Table = this;
				indexes[indexName] = index;
			}
			return index;
		}

		/// <summary>
		/// Gets the <see cref="UniqueKey"/> identified by the name.
		/// </summary>
		/// <param name="keyName">The name of the <see cref="UniqueKey"/> to get.</param>
		/// <returns>
		/// The <see cref="UniqueKey"/> identified by the name.  If the <see cref="UniqueKey"/>
		/// identified by the name does not exist then it is created.
		/// </returns>
		public UniqueKey GetUniqueKey(string keyName)
		{
			UniqueKey result;
			uniqueKeys.TryGetValue(keyName, out result);
			return result;
		}

		public UniqueKey AddUniqueKey(UniqueKey uniqueKey)
		{
			UniqueKey current = GetUniqueKey(uniqueKey.Name);
			if (current != null)
			{
				throw new MappingException("UniqueKey " + uniqueKey.Name + " already exists!");
			}
			uniqueKeys[uniqueKey.Name] = uniqueKey;
			return uniqueKey;
		}

		public UniqueKey GetOrCreateUniqueKey(string keyName)
		{
			UniqueKey uk = GetUniqueKey(keyName);

			if (uk == null)
			{
				uk = new UniqueKey();
				uk.Name = keyName;
				uk.Table = this;
				uniqueKeys[keyName] = uk;
			}
			return uk;
		}

		public virtual void CreateForeignKeys() {}

		public virtual ForeignKey CreateForeignKey(string keyName, IEnumerable<Column> keyColumns, string referencedEntityName)
		{
			return CreateForeignKey(keyName, keyColumns, referencedEntityName, null);
		}

		/// <summary>
		/// Create a <see cref="ForeignKey"/> for the columns in the Table.
		/// </summary>
		/// <param name="keyName"></param>
		/// <param name="keyColumns">An <see cref="IList"/> of <see cref="Column"/> objects.</param>
		/// <param name="referencedEntityName"></param>
		/// <param name="referencedColumns"></param>
		/// <returns>
		/// A <see cref="ForeignKey"/> for the columns in the Table.  
		/// </returns>
		/// <remarks>
		/// This does not necessarily create a <see cref="ForeignKey"/>, if
		/// one already exists for the columns then it will return an 
		/// existing <see cref="ForeignKey"/>.
		/// </remarks>
		public virtual ForeignKey CreateForeignKey(string keyName, IEnumerable<Column> keyColumns, string referencedEntityName,
		                                           IEnumerable<Column> referencedColumns)
		{
			IEnumerable<Column> kCols = keyColumns;
			IEnumerable<Column> refCols = referencedColumns;

			var key = new ForeignKeyKey(kCols, referencedEntityName, refCols);

			ForeignKey fk;
			foreignKeys.TryGetValue(key, out fk);

			if (fk == null)
			{
				fk = new ForeignKey();
				if (!string.IsNullOrEmpty(keyName))
				{
					fk.Name = keyName;
				}
				else
				{
					fk.Name = "FK" + UniqueColumnString(kCols, referencedEntityName);
					//TODO: add referencedClass to disambiguate to FKs on the same columns, pointing to different tables
				}
				fk.Table = this;
				foreignKeys.Add(key, fk);
				fk.ReferencedEntityName = referencedEntityName;
				fk.AddColumns(kCols);
				if (referencedColumns != null)
				{
					fk.AddReferencedColumns(refCols);
				}
			}

			if (!string.IsNullOrEmpty(keyName))
			{
				fk.Name = keyName;
			}

			return fk;
		}

		public virtual UniqueKey CreateUniqueKey(IList<Column> keyColumns)
		{
			string keyName = "UK" + UniqueColumnString(keyColumns);
			UniqueKey uk = GetOrCreateUniqueKey(keyName);
			uk.AddColumns(keyColumns);
			return uk;
		}

		/// <summary>
		/// Generates a unique string for an <see cref="ICollection"/> of 
		/// <see cref="Column"/> objects.
		/// </summary>
		/// <param name="uniqueColumns">An <see cref="ICollection"/> of <see cref="Column"/> objects.</param>
		/// <returns>
		/// An unique string for the <see cref="Column"/> objects.
		/// </returns>
		public string UniqueColumnString(IEnumerable uniqueColumns)
		{
			return UniqueColumnString(uniqueColumns, null);
		}

		public string UniqueColumnString(IEnumerable iterator, string referencedEntityName)
		{
			// NH Different implementation (NH-1339)
			int result = 37;
			if (referencedEntityName != null)
			{
				result ^= referencedEntityName.GetHashCode();
			}

			foreach (object o in iterator)
			{
				result ^= o.GetHashCode();
			}
			return (name.GetHashCode().ToString("X") + result.GetHashCode().ToString("X"));
		}

		/// <summary>
		/// Sets the Identifier of the Table.
		/// </summary>
		/// <param name="identifierValue">The <see cref="SimpleValue"/> that represents the Identifier.</param>
		public void SetIdentifierValue(SimpleValue identifierValue)
		{
			idValue = identifierValue;
		}

		/// <summary>
		/// 
		/// </summary>
		/// <param name="constraint"></param>
		public void AddCheckConstraint(string constraint)
		{
			checkConstraints.Add(constraint);
		}

		internal void SetHasDenormalizedTables()
		{
			hasDenormalizedTables = true;
		}

		public virtual bool ContainsColumn(Column column)
		{
			return columns.ContainsValue(column);
		}

		/// <summary> Return the column which is identified by column provided as argument. </summary>
		/// <param name="column">column with atleast a name. </param>
		/// <returns> 
		/// The underlying column or null if not inside this table.
		/// Note: the instance *can* be different than the input parameter, but the name will be the same.
		/// </returns>
		public virtual Column GetColumn(Column column)
		{
			if (column == null)
			{
				return null;
			}

			Column result;
			columns.TryGetValue(column.CanonicalName, out result);

			return column.Equals(result) ? result : null;
		}

		private static bool AreSameColumns(ICollection<Column> col1, ICollection<Column> col2)
		{
			if (col1.Count != col2.Count)
			{
				return false;
			}
			foreach (Column column in col1)
			{
				if (!col2.Contains(column))
				{
					return false;
				}
			}
			foreach (Column column in col2)
			{
				if (!col1.Contains(column))
				{
					return false;
				}
			}
			return true;
		}

		public virtual string[] SqlCommentStrings(Dialect.Dialect dialect, string defaultCatalog, string defaultSchema)
		{
			var comments = new List<string>();
			if (dialect.SupportsCommentOn)
			{
				string tableName = GetQualifiedName(dialect, defaultCatalog, defaultSchema);
				if (!string.IsNullOrEmpty(comment))
				{
					StringBuilder buf =
						new StringBuilder().Append("comment on table ").Append(tableName).Append(" is '").Append(comment).Append("'");
					comments.Add(buf.ToString());
				}
				foreach (Column column in ColumnIterator)
				{
					string columnComment = column.Comment;
					if (columnComment != null)
					{
						StringBuilder buf =
							new StringBuilder().Append("comment on column ").Append(tableName).Append('.').Append(
								column.GetQuotedName(dialect)).Append(" is '").Append(columnComment).Append("'");
						comments.Add(buf.ToString());
					}
				}
			}
			return comments.ToArray();
		}

		public virtual string SqlTemporaryTableCreateString(Dialect.Dialect dialect, IMapping mapping)
		{
			StringBuilder buffer = new StringBuilder(dialect.CreateTemporaryTableString).Append(' ').Append(name).Append(" (");
			bool commaNeeded = false;
			foreach (Column column in ColumnIterator)
			{
				buffer.Append(column.GetQuotedName(dialect)).Append(' ');
				buffer.Append(column.GetSqlType(dialect, mapping));

				if (commaNeeded)
				{
					buffer.Append(StringHelper.CommaSpace);
				}
				commaNeeded = true;

				if (column.IsNullable)
				{
					buffer.Append(dialect.NullColumnString);
				}
				else
				{
					buffer.Append(" not null");
				}
			}

			buffer.Append(") ");
			buffer.Append(dialect.CreateTemporaryTablePostfix);
			return buffer.ToString();
		}

		public override string ToString()
		{
			StringBuilder buf = new StringBuilder().Append(GetType().FullName).Append('(');
			if (Catalog != null)
			{
				buf.Append(Catalog + ".");
			}
			if (Schema != null)
			{
				buf.Append(Schema + ".");
			}
			buf.Append(Name).Append(')');
			return buf.ToString();
		}

		public void ValidateColumns(Dialect.Dialect dialect, IMapping mapping, ITableMetadata tableInfo)
		{
			IEnumerable<Column> iter = ColumnIterator;
			foreach (Column column in iter)
			{
				IColumnMetadata columnInfo = tableInfo.GetColumnMetadata(column.Name);

				if (columnInfo == null)
				{
					throw new HibernateException(string.Format("Missing column: {0} in {1}", column.Name,
					                                           Qualify(tableInfo.Catalog, tableInfo.Schema, tableInfo.Name)));
				}

				else
				{
					//TODO: Add new method to ColumnMetadata :getTypeCode
					bool typesMatch = column.GetSqlType(dialect, mapping).ToLower().StartsWith(columnInfo.TypeName.ToLower());
						//|| columnInfo.get() == column.GetSqlTypeCode(mapping);
					if (!typesMatch)
					{
						throw new HibernateException(string.Format("Wrong column type in {0} for column {1}. Found: {2}, Expected {3}",
						                                           Qualify(tableInfo.Catalog, tableInfo.Schema, tableInfo.Name),
						                                           column.Name, columnInfo.TypeName.ToLower(),
						                                           column.GetSqlType(dialect, mapping)));
					}
				}
			}
		}

		public static string Qualify(string catalog, string schema, string table)
		{
			var qualifiedName = new StringBuilder(100);
			if (catalog != null)
			{
				qualifiedName.Append(catalog).Append('.');
			}
			if (schema != null)
			{
				qualifiedName.Append(schema).Append('.');
			}
			return qualifiedName.Append(table).ToString();
		}

		#region Nested type: ForeignKeyKey
		[Serializable]
		internal class ForeignKeyKey : IEqualityComparer<ForeignKeyKey>
		{
			internal List<Column> columns;
			internal string referencedClassName;
			internal List<Column> referencedColumns;

			internal ForeignKeyKey(IEnumerable<Column> columns, string referencedClassName, IEnumerable<Column> referencedColumns)
			{
				this.referencedClassName = referencedClassName;
				this.columns = new List<Column>(columns);
				if (referencedColumns != null)
				{
					this.referencedColumns = new List<Column>(referencedColumns);
				}
				else
				{
					this.referencedColumns = new List<Column>();
				}
			}

			#region IEqualityComparer<ForeignKeyKey> Members

			public bool Equals(ForeignKeyKey x, ForeignKeyKey y)
			{
				// NH : Different implementation to prevent NH930 (look test)
				return //y.referencedClassName.Equals(x.referencedClassName) &&
					CollectionHelper.CollectionEquals<Column>(y.columns, x.columns)
					&& CollectionHelper.CollectionEquals<Column>(y.referencedColumns, x.referencedColumns);
			}

			public int GetHashCode(ForeignKeyKey obj)
			{
				int result = CollectionHelper.GetHashCode(obj.columns) ^ CollectionHelper.GetHashCode(obj.referencedColumns);
				return result;
			}

			#endregion

			public override int GetHashCode()
			{
				return GetHashCode(this);
			}

			public override bool Equals(object other)
			{
				var that = other as ForeignKeyKey;
				if (that != null)
				{
					return Equals(this, that);
				}
				else
				{
					return false;
				}
			}
		}

		#endregion
	}
}
For more information: Info@semanticdesigns.com    Follow us at Twitter: @SemanticDesigns

C# Smart Differencer
Example