SQL Server to .Net Data Type Mappings TableSQL Server and the .NET Framework are based on different type systems. This handy table will help you to perform data type mappings.
The .NET Framework Decimal structure has a maximum scale of 28, whereas the SQL Server decimal and numeric data types have a maximum scale of 38. To maintain data integrity when reading and writing data, the SqlDataReader exposes SQL Server-specific typed accessor methods that return objects of System.Data.SqlTypes as well as accessor methods that return .NET Framework types. Both SQL Server types and .NET Framework types are also represented by enumerations in the DbType and SqlDbType classes, which you can use when specifying SqlParameter data types.
The following table shows the inferred .NET Framework type, the DbType and SqlDbType enumerations, and the accessor methods for the SqlDataReader.
SQL Server <> .Net Data Type Mapping Conversion
| SQL Server Database Engine type | .NET Framework type | SqlDbType enumeration | SqlDataReader SqlTypes typed accessor | DbType enumeration | SqlDataReader DbType typed accessor |
|---|---|---|---|---|---|
| bigint | Int64 | BigInt | GetSqlInt64 | Int64 | GetInt64 |
| binary | Byte[] | VarBinary | GetSqlBinary | Binary | GetBytes |
| bit | Boolean | Bit | GetSqlBoolean | Boolean | GetBoolean |
| char | String || Char[] | Char | GetSqlString | AnsiStringFixedLength (String) | GetString || GetChars |
| date 1 (SQL Server 2008 and later) | DateTime | Date 1 | GetSqlDateTime | Date 1 | GetDateTime |
| datetime | DateTime | DateTime | GetSqlDateTime | DateTime | GetDateTime |
| datetime2 (SQL Server 2008 and later) | DateTime | DateTime2 | None | DateTime2 | GetDateTime |
| datetimeoffset (SQL Server 2008 and later) | DateTimeOffset | DateTimeOffset | none | DateTimeOffset | GetDateTimeOffset |
| decimal | Decimal | Decimal | GetSqlDecimal | Decimal | GetDecimal |
| FILESTREAM attribute (varbinary(max)) | Byte[] | VarBinary | GetSqlBytes | Binary | GetBytes |
| float | Double | Float | GetSqlDouble | Double | GetDouble |
| image | Byte[] | Binary | GetSqlBinary | Binary | GetBytes |
| int | Int32 | Int | GetSqlInt32 | Int32 | GetInt32 |
| money | Decimal | Money | GetSqlMoney | Decimal | GetDecimal |
| nchar | String || Char[] | NChar | GetSqlString | StringFixedLength | GetString || GetChars |
| ntext | String || Char[] | NText | GetSqlString | String | GetString || GetChars |
| numeric | Decimal | Decimal | GetSqlDecimal | Decimal | GetDecimal |
| nvarchar | String || Char[] | NVarChar | GetSqlString | String | GetString || GetChars |
| real | Single | Real | GetSqlSingle | Single | GetFloat |
| rowversion | Byte[] | Timestamp | GetSqlBinary | Binary | GetBytes |
| smalldatetime | DateTime | DateTime | GetSqlDateTime | DateTime | GetDateTime |
| smallint | Int16 | SmallInt | GetSqlInt16 | Int16 | GetInt16 |
| smallmoney | Decimal | SmallMoney | GetSqlMoney | Decimal | GetDecimal |
| sql_variant | Object 2 | Variant | GetSqlValue 2 | Object | GetValue 2 |
| text | String || Char[] | Text | GetSqlString | String | GetString || GetChars |
| time (SQL Server 2008 and later) | TimeSpan | Time | none | Time | GetDateTime |
| timestamp | Byte[] | Timestamp | GetSqlBinary | Binary | GetBytes |
| tinyint | Byte | TinyInt | GetSqlByte | Byte | GetByte |
| uniqueidentifier | Guid | UniqueIdentifier | GetSqlGuid | Guid | GetGuid |
| varbinary | Byte[] | VarBinary | GetSqlBinary | Binary | GetBytes |
| varchar | String || Char[] | VarChar | GetSqlString | AnsiString, String | GetString || GetChars |
| xml | Xml | Xml | GetSqlXml | Xml | none |
- You cannot set the DbType property of a SqlParameter to SqlDbType.Date.
- Use a specific typed accessor if you know the underlying type of the sql_variant.
