mono/mcs/class/System.Data/System.Data.SqlClient/SqlCommandBuilder.cs

//
// System.Data.Common.CommandBuilder.cs
//
// Author:
//   Tim Coleman ([email protected])
//
// Copyright (C) Tim Coleman, 2002
//

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Text;

namespace System.Data.SqlClient {
	public sealed class SqlCommandBuilder : Component
	{
		#region Fields

		DataTable dbSchemaTable;
		SqlDataAdapter adapter;
		string quotePrefix;
		string quoteSuffix;
		string[] columnNames;
		string tableName;
	
		SqlCommand deleteCommand;
		SqlCommand insertCommand;
		SqlCommand updateCommand;

		// Used to construct WHERE clauses
		static readonly string clause1 = "({0} IS NULL AND {1} IS NULL)";
		static readonly string clause2 = "({0} = {1})";

		#endregion // Fields

		#region Constructors

		public SqlCommandBuilder () 
		{
			dbSchemaTable = null;
			adapter = null;
			quoteSuffix = String.Empty;
			quotePrefix = String.Empty;
		}

		public SqlCommandBuilder (SqlDataAdapter adapter)
			: this ()
		{
			DataAdapter = adapter;
		}

		#endregion // Constructors

		#region Properties

		public SqlDataAdapter DataAdapter {
			get { return adapter; }
			set { 
				adapter = value; 
				if (adapter != null)
					adapter.RowUpdating += new SqlRowUpdatingEventHandler (RowUpdatingHandler);
			}
		}

		private string QuotedTableName {
			get { return GetQuotedString (tableName); }
		}

		public string QuotePrefix {
			get { return quotePrefix; }
			set { 
				if (dbSchemaTable != null)
					throw new InvalidOperationException ("The QuotePrefix and QuoteSuffix properties cannot be changed once an Insert, Update, or Delete command has been generated.");
				quotePrefix = value; 
			}
		}

		public string QuoteSuffix {
			get { return quoteSuffix; }
			set {
				if (dbSchemaTable != null)
					throw new InvalidOperationException ("The QuotePrefix and QuoteSuffix properties cannot be changed once an Insert, Update, or Delete command has been generated.");
				quoteSuffix = value; 
			}
		}

		private SqlCommand SourceCommand {
			get {
				if (adapter != null)
					return adapter.SelectCommand;
				return null;
			}
		}

		#endregion // Properties

		#region Methods

		private void BuildCache (bool closeConnection)
		{
			SqlCommand sourceCommand = SourceCommand;
			if (sourceCommand == null)
				throw new InvalidOperationException ("The DataAdapter.SelectCommand property needs to be initialized.");
			SqlConnection connection = sourceCommand.Connection;
			if (connection == null)
				throw new InvalidOperationException ("The DataAdapter.SelectCommand.Connection property needs to be initialized.");
				
			if (dbSchemaTable == null) {
				if (connection.State == ConnectionState.Open)
					closeConnection = false;	
				else
					connection.Open ();
	
				SqlDataReader reader = sourceCommand.ExecuteReader (CommandBehavior.SchemaOnly | CommandBehavior.KeyInfo);
				dbSchemaTable = reader.GetSchemaTable ();
				if (closeConnection)
					connection.Close ();	
				BuildInformation (dbSchemaTable);
			}
		}
		
		private void BuildInformation (DataTable schemaTable)
		{
			tableName = String.Empty;
			foreach (DataRow schemaRow in schemaTable.Rows) {
				if (tableName == String.Empty) 
					tableName = (string) schemaRow ["BaseTableName"];
				if (tableName != (string) schemaRow["BaseTableName"])
					throw new InvalidOperationException ("Dynamic SQL generation is not supported against multiple base tables.");
			}
			dbSchemaTable = schemaTable;
		}

		private SqlCommand CreateDeleteCommand (DataRow row, DataTableMapping tableMapping) 
		{
			// If no table was found, then we can't do an delete
			if (QuotedTableName == String.Empty)
				return null;

			CreateNewCommand (ref deleteCommand);

			string command = String.Format ("DELETE FROM {0} ", QuotedTableName);
			StringBuilder columns = new StringBuilder ();
			StringBuilder where = new StringBuilder ();

			int parmIndex = 1;

			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if (!IncludedInWhereClause (schemaRow)) 
					continue;

				if (where.Length > 0) 
					where.Append (" AND ");

				bool isKey = (bool) schemaRow ["IsKey"];
				SqlParameter parameter = null;

				if (!isKey) {
					parameter = deleteCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));
					where.Append ("(");
					where.Append (String.Format (clause1, GetQuotedString (parameter.SourceColumn), parameter.ParameterName));
					where.Append (" OR ");
				}
					
				parameter = deleteCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));
				if (row != null)
					parameter.Value = row [parameter.SourceColumn, DataRowVersion.Current];
				where.Append (String.Format (clause2, GetQuotedString (parameter.SourceColumn), parameter.ParameterName));

				if (!isKey)
					where.Append (")");
			}

			// We're all done, so bring it on home
			string sql = String.Format ("{0} WHERE ( {1} )", command, where.ToString ());
			deleteCommand.CommandText = sql;
			return deleteCommand;
		}

		private SqlCommand CreateInsertCommand (DataRow row, DataTableMapping tableMapping) 
		{
			if (QuotedTableName == String.Empty)
				return null;

			CreateNewCommand (ref insertCommand);

			string command = String.Format ("INSERT INTO {0}", QuotedTableName);
			string sql;
			StringBuilder columns = new StringBuilder ();
			StringBuilder values = new StringBuilder ();

			int parmIndex = 1;
			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if (!IncludedInInsert (schemaRow))
					continue;

				if (parmIndex > 1) {
					columns.Append (" , ");
					values.Append (" , ");
				}

				SqlParameter parameter = insertCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));
				if (row != null)
					parameter.Value = row [parameter.SourceColumn, DataRowVersion.Proposed];
				columns.Append (GetQuotedString (parameter.SourceColumn));
				values.Append (parameter.ParameterName);
			}

			sql = String.Format ("{0}( {1} ) VALUES ( {2} )", command, columns.ToString (), values.ToString ());
			insertCommand.CommandText = sql;
			return insertCommand;
		}

		private void CreateNewCommand (ref SqlCommand command)
		{
			SqlCommand sourceCommand = SourceCommand;
			if (command == null) {
				command = sourceCommand.Connection.CreateCommand ();
				command.CommandTimeout = sourceCommand.CommandTimeout;
				command.Transaction = sourceCommand.Transaction;
			}
			command.CommandType = CommandType.Text;
			command.UpdatedRowSource = UpdateRowSource.None;
		}

		private SqlCommand CreateUpdateCommand (DataRow row, DataTableMapping tableMapping) 
		{
			// If no table was found, then we can't do an update
			if (QuotedTableName == String.Empty)
				return null;

			CreateNewCommand (ref updateCommand);

			string command = String.Format ("UPDATE {0} SET ", QuotedTableName);
			StringBuilder columns = new StringBuilder ();
			StringBuilder where = new StringBuilder ();

			int parmIndex = 1;

			// First, create the X=Y list for UPDATE
			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if (columns.Length > 0) 
					columns.Append (" , ");

				SqlParameter parameter = updateCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));
				if (row != null)
					parameter.Value = row [parameter.SourceColumn, DataRowVersion.Proposed];
				columns.Append (String.Format ("{0} = {1}", GetQuotedString (parameter.SourceColumn), parameter.ParameterName));
			}

			// Now, create the WHERE clause.  This may be optimizable, but it would be ugly to incorporate
			// into the loop above.  "Premature optimization is the root of all evil." -- Knuth
			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if (!IncludedInWhereClause (schemaRow)) 
					continue;

				if (where.Length > 0) 
					where.Append (" AND ");

				bool isKey = (bool) schemaRow ["IsKey"];
				SqlParameter parameter = null;

				if (!isKey) {
					parameter = updateCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));
					where.Append ("(");
					where.Append (String.Format (clause1, GetQuotedString (parameter.SourceColumn), parameter.ParameterName));
					where.Append (" OR ");
				}
					
				parameter = updateCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));
				if (row != null)
					parameter.Value = row [parameter.SourceColumn, DataRowVersion.Current];
				where.Append (String.Format (clause2, GetQuotedString (parameter.SourceColumn), parameter.ParameterName));

				if (!isKey)
					where.Append (")");
			}

			// We're all done, so bring it on home
			string sql = String.Format ("{0}{1} WHERE ( {2} )", command, columns.ToString (), where.ToString ());
			updateCommand.CommandText = sql;
			return updateCommand;
		}

		private SqlParameter CreateParameter (int parmIndex, DataRow schemaRow)
		{
			string name = String.Format ("@p{0}", parmIndex);
			string sourceColumn = (string) schemaRow ["BaseColumnName"];
			SqlDbType sqlDbType = (SqlDbType) schemaRow ["ProviderType"];
			int size = (int) schemaRow ["ColumnSize"];

			return new SqlParameter (name, sqlDbType, size, sourceColumn);
		}

		public static void DeriveParameters (SqlCommand command)
		{
			command.DeriveParameters ();
		}

		[MonoTODO]
		protected override void Dispose (bool disposing)
		{
		}

		public SqlCommand GetDeleteCommand ()
		{
			BuildCache (true);
			return CreateDeleteCommand (null, null);
		}

		public SqlCommand GetInsertCommand ()
		{
			BuildCache (true);
			return CreateInsertCommand (null, null);
		}

		private string GetQuotedString (string value)
		{
			if (value == String.Empty || value == null)
				return value;
			if (quotePrefix == String.Empty && quoteSuffix == String.Empty)
				return value;
			return String.Format ("{0}{1}{2}", quotePrefix, value, quoteSuffix);
		}

		public SqlCommand GetUpdateCommand ()
		{
			BuildCache (true);
			return CreateUpdateCommand (null, null);
		}

		private bool IncludedInInsert (DataRow schemaRow)
		{
			// If the parameter has one of these properties, then we don't include it in the insert:
			// AutoIncrement, Hidden, Expression, RowVersion, ReadOnly

			if ((bool) schemaRow ["IsAutoIncrement"])
				return false;
			if ((bool) schemaRow ["IsHidden"])
				return false;
			if ((bool) schemaRow ["IsExpression"])
				return false;
			if ((bool) schemaRow ["IsRowVersion"])
				return false;
			if ((bool) schemaRow ["IsReadOnly"])
				return false;
			return true;
		}

		private bool IncludedInUpdate (DataRow schemaRow)
		{
			// If the parameter has one of these properties, then we don't include it in the insert:
			// AutoIncrement, Hidden, RowVersion

			if ((bool) schemaRow ["IsAutoIncrement"])
				return false;
			if ((bool) schemaRow ["IsHidden"])
				return false;
			if ((bool) schemaRow ["IsRowVersion"])
				return false;
			return true;
		}

		private bool IncludedInWhereClause (DataRow schemaRow)
		{
			if ((bool) schemaRow ["IsLong"])
				return false;
			return true;
		}

		[MonoTODO]
		public void RefreshSchema () 
		{
			tableName = String.Empty;
			dbSchemaTable = null;
		}

		#endregion // Methods

		#region Event Handlers

		private void RowUpdatingHandler (object sender, SqlRowUpdatingEventArgs e)
		{
			if (e.Status != UpdateStatus.Continue)
				return;

			switch (e.StatementType) {
			case StatementType.Delete:
				deleteCommand = e.Command;
				break;
			case StatementType.Insert:
				insertCommand = e.Command;
				break;
			case StatementType.Update:
				updateCommand = e.Command;
				break;
			default:
				return;
			}

			BuildCache (false);

			switch (e.StatementType) {
			case StatementType.Delete:
				e.Command = CreateDeleteCommand (e.Row, e.TableMapping);
				e.Status = UpdateStatus.Continue;
				break;
			case StatementType.Insert:
				e.Command = CreateInsertCommand (e.Row, e.TableMapping);
				e.Status = UpdateStatus.Continue;
				break;
			case StatementType.Update:
				e.Command = CreateUpdateCommand (e.Row, e.TableMapping);
				e.Status = UpdateStatus.Continue;
				break;
			}
			
			if (e.Command != null && e.Row != null) {
				e.Row.AcceptChanges ();
				e.Status = UpdateStatus.SkipCurrentRow;
			}
		}

		#endregion // Event Handlers
	}
}