SQL Server Data Type Mapping (ADO)

http://msdn.microsoft.com/zh-cn/library/cc716729 (vs.90). aspxSQL Server Data Type Mapping (ADO) . NET Framework 3.5Other versions3 out of 3 rated this helpful -rate this topic

Updated: November 2007

SQL Server and the. NET Framework are based on different types of systems. For example, the maximum size of the. NET Framework decimal structure is 28, while SQL Server's decimal and numeric data types have a maximum size of 38. To maintain data integrity while reading and writing data,SqlDataReader exposes SQL Server-specific typed accessor methods for returning System.Data.SqlTypes objects and for returning. NET Accessor methods for the Framework type. SQL Server types and. NET Framework types can also be represented by enumerations in the DbType and SqlDbType classes, which are available when you specify SqlParameter data types.

The following table shows the inferred. NET Framework types,DbType and SqlDbType enumerations, and accessor methods for SqlDataReader.

SQL Server Database Engine type	. NET Framework Types	SqlDbType Enumeration	SqlDataReader SqlTypes Typed accessors	DbType Enumeration	SqlDataReader DbType Typed accessors
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 (For SQL Server 2008 only)	Datetime	Date	GetSqlDateTime	Date	GetDateTime
Datetime	Datetime	Datetime	GetSqlDateTime	Datetime	GetDateTime
DateTime2 (For SQL Server 2008 only)	DateTime2	DateTime2	GetSqlDateTime	DateTime2	GetDateTime
DateTimeOffset (For SQL Server 2008 only)	DateTimeOffset	DateTimeOffset	None	DateTimeOffset	Getdatetimeoffset
Decimal	Decimal	Decimal	GetSqlDecimal	Decimal	Getdecimal
FILESTREAM Property (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	GetSqlDecimal	Decimal	Getdecimal
sql_variant	object*	Variant	Getsqlvalue *	Object	GetValue *
Text	String Char[]	Text	GetSqlString	String	GetString GetChars
Time (For SQL Server 2008 only)	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

* If the underlying type of sql_variant is known, a specific typed accessor is used.

SQL Server Books Online reference

For more information about SQL Server data types, see SQL Server Books Online that corresponds to the version of SQL Server that you are using.

SQL Server 2000	SQL Server 2005	SQL Server 2008
Data type	Data type (Database engine)	Data type (Database engine)

Please seeConceptconfiguration parameters and parameter data Types (ADO)Other resourcesSQL Server data types and ADOSQL Server binary and large Value data (ADO)data type mappings in ADO

SQL Server Data Type Mapping (ADO)