DBSchemaTable.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / Common / DBSchemaTable.cs / 1 / DBSchemaTable.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
 
namespace System.Data.Common {
 
    using System;
    using System.Data;
    using System.Data.ProviderBase;
    using System.Diagnostics; 

    sealed internal class DbSchemaTable { 
 
        private enum ColumnEnum {
            ColumnName, 
            ColumnOrdinal,
            ColumnSize,
            BaseServerName,
            BaseCatalogName, 
            BaseColumnName,
            BaseSchemaName, 
            BaseTableName, 
            IsAutoIncrement,
            IsUnique, 
            IsKey,
            IsRowVersion,
            DataType,
            ProviderSpecificDataType, 
            AllowDBNull,
            ProviderType, 
            IsExpression, 
            IsHidden,
            IsLong, 
            IsReadOnly,
            SchemaMappingUnsortedIndex,
        }
 
        static readonly private string[] DBCOLUMN_NAME = new string[] {
            SchemaTableColumn.ColumnName, 
            SchemaTableColumn.ColumnOrdinal, 
            SchemaTableColumn.ColumnSize,
            SchemaTableOptionalColumn.BaseServerName, 
            SchemaTableOptionalColumn.BaseCatalogName,
            SchemaTableColumn.BaseColumnName,
            SchemaTableColumn.BaseSchemaName,
            SchemaTableColumn.BaseTableName, 
            SchemaTableOptionalColumn.IsAutoIncrement,
            SchemaTableColumn.IsUnique, 
            SchemaTableColumn.IsKey, 
            SchemaTableOptionalColumn.IsRowVersion,
            SchemaTableColumn.DataType, 
            SchemaTableOptionalColumn.ProviderSpecificDataType,
            SchemaTableColumn.AllowDBNull,
            SchemaTableColumn.ProviderType,
            SchemaTableColumn.IsExpression, 
            SchemaTableOptionalColumn.IsHidden,
            SchemaTableColumn.IsLong, 
            SchemaTableOptionalColumn.IsReadOnly, 
            DbSchemaRow.SchemaMappingUnsortedIndex,
        }; 

        internal DataTable dataTable;
        private DataColumnCollection columns;
        private DataColumn[] columnCache = new DataColumn[DBCOLUMN_NAME.Length]; 
        private bool _returnProviderSpecificTypes;
 
        internal DbSchemaTable(DataTable dataTable, bool returnProviderSpecificTypes) { 
            this.dataTable = dataTable;
            this.columns = dataTable.Columns; 
            _returnProviderSpecificTypes = returnProviderSpecificTypes;
        }

        internal DataColumn ColumnName      { get { return CachedDataColumn(ColumnEnum.ColumnName);}} 
        internal DataColumn Size            { get { return CachedDataColumn(ColumnEnum.ColumnSize);}}
        internal DataColumn BaseServerName  { get { return CachedDataColumn(ColumnEnum.BaseServerName);}} 
        internal DataColumn BaseColumnName  { get { return CachedDataColumn(ColumnEnum.BaseColumnName);}} 
        internal DataColumn BaseTableName   { get { return CachedDataColumn(ColumnEnum.BaseTableName);}}
        internal DataColumn BaseCatalogName { get { return CachedDataColumn(ColumnEnum.BaseCatalogName);}} 
        internal DataColumn BaseSchemaName  { get { return CachedDataColumn(ColumnEnum.BaseSchemaName);}}
        internal DataColumn IsAutoIncrement { get { return CachedDataColumn(ColumnEnum.IsAutoIncrement);}}
        internal DataColumn IsUnique        { get { return CachedDataColumn(ColumnEnum.IsUnique);}}
        internal DataColumn IsKey           { get { return CachedDataColumn(ColumnEnum.IsKey);}} 
        internal DataColumn IsRowVersion    { get { return CachedDataColumn(ColumnEnum.IsRowVersion);}}
 
        internal DataColumn AllowDBNull              { get { return CachedDataColumn(ColumnEnum.AllowDBNull);}} 
        internal DataColumn IsExpression             { get { return CachedDataColumn(ColumnEnum.IsExpression);}}
        internal DataColumn IsHidden                 { get { return CachedDataColumn(ColumnEnum.IsHidden);}} 
        internal DataColumn IsLong                   { get { return CachedDataColumn(ColumnEnum.IsLong);}}
        internal DataColumn IsReadOnly               { get { return CachedDataColumn(ColumnEnum.IsReadOnly);}}

        internal DataColumn UnsortedIndex   { get { return CachedDataColumn(ColumnEnum.SchemaMappingUnsortedIndex);}} 

        internal DataColumn DataType { 
            get { 
                if (_returnProviderSpecificTypes) {
                    return CachedDataColumn(ColumnEnum.ProviderSpecificDataType, ColumnEnum.DataType); 
                }
                return CachedDataColumn(ColumnEnum.DataType);
            }
        } 

        private DataColumn CachedDataColumn(ColumnEnum column) { 
            return CachedDataColumn(column, column); 
        }
 
        private DataColumn CachedDataColumn(ColumnEnum column, ColumnEnum column2) {
            DataColumn dataColumn = columnCache[(int) column];
            if (null == dataColumn) {
                int index = columns.IndexOf(DBCOLUMN_NAME[(int) column]); 
                if ((-1 == index) && (column != column2)) {
                    index = columns.IndexOf(DBCOLUMN_NAME[(int) column2]); 
                } 
                if (-1 != index) {
                    dataColumn = columns[index]; 
                    columnCache[(int) column] = dataColumn;
                }
            }
            return dataColumn; 
        }
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK