| The SQL Server provider provides access to a SQL Server database (Version 7.0 or later) through the optimized Tabular Data Stream (TDS) interface (see Table A-1). To connect to the pre-7.0 version of SQL Server, use the OLE DB .NET data provider with the SQL Server OLE DB provider (SQLOLEDB). The connection-specific types are found in the System.Data.SqlClient namespace. Table A-1. SQL Server provider classes | Interface | Implementing class | | IDbConnection | SqlConnection | | IDbCommand | SqlCommand | | IDataParameter , IDbDataParameter | SqlParameter | | IDataReader , IDataRecord | SqlDataReader | | IDataAdapter, IDbDataAdapter | SqlDataAdapter | | IDbTransaction | SqlTransaction | The SQL Server provider also provides .NET structures that map exactly to SQL Server types in the System.Data.SqlTypes namespace (see Table A-2). You can use SqlDataReader methods such as GetSqlMoney( ) and GetSqlDataTime( ) to retrieve values using these types (as described in Chapter 2). Table A-2. Native SQL Server data types | SQL Server data type | Mapped .NET Type(System namespace) | Underlying .NET type(SqlTypes namespace) | | Binary | Byte[] | SqlBinary | | Bigint | Int64 | SqlInt64 | | Char | String | SqlString | | Datetime | Datetime | SqlDateTime | | Decimal | Decimal | SqlDecimal | | Float | Double | SqlDouble | | Image | Byte[] | SqlBinary | | Int | Int32 | SqlInt32 | | Money | Decimal | SqlMoney | | Nchar | String | SqlString | | Ntext | String | SqlString | | Nvarchar | String | SqlString | | Numeric | Decimal | SqlDecimal | | Real | Single | SqlSingle | | Smalldatetime | Datetime | SqlDateTime | | Smallint | Int16 | SqlInt16 | | Smallmoney | Decimal | SqlMoney | | sql_variant | Object | System.Object (base class) | | Sysname | String | SqlString | | Text | String | SqlString | | Timestamp | Datetime | SqlBinary | | Tinyint | Byte | SqlByte | | Varbinary | Byte[] | SqlBinary | | Varchar | String | SqlString | | Uniqueidentifier | Guid | SqlGuid | |