The correspondence between SQL Server and data types in C #

corresponding Relationship table

SQL Server http://hovertree.com/menu/sqlserver/		C#		Codesmith
Data type	Range of values	Data type	Range of values	Null value instead of value	Data type
bigint	-2^63 (-9,223,372,036,854,775,807) to 2^63-1 (9,223,372,036,854,775,807)	Int64	-9,223,372,036,854,775,808; hexadecimal 0x8000000000000000 to 9,223,372,036,854,775,807; hexadecimal 0x7fffffffffffffff	Int64.minvalue	Int64
Binary	A fixed-length n-byte binary data. N must be from 1 to 8,000. The storage space size is n+4 bytes.	Byte[]		Null	Binary
Bit	True,false	Enum	0,1,-1 (instead of using an enumeration variable) public enum Bitnull {False, True, Null =-1};	-1	Boolean
Char	A fixed-length, non-Unicode character data with a length of n bytes. n must be a numeric value between 1 and 8,000. The storage size is n bytes.	String		Null	Ansistringfixedlength
Datetime	Store dates from January 1, 1753 to December 31, 9999 (each value requires 8 bytes of storage space)	Datetime	January 1, 01 00:00:00.0000000 to December 31, 9999 23:59:59.9999999	1753-01-01 0:00:00	Datetime
Decimal	From-10^38 +1 to 10^38-1	Decimal	-79,228,162,514,264,337,593,543,950,335 to 79,228,162,514,264,337,593,543,950,335	Decimal.minvalue	Decimal
Float	Floating-point digital data from 1.79E + 308 to 1.79E + 308	Double	-1.79769313486232e308 to +1.79769313486232e308	Double.minvalue	Double
Image	Variable-length binary data is between 0 and 231-1 (2,147,483,647) bytes.	Byte[]		Null	Binary
Int	Integer data from -2^31 (-2,147,483,648) to 2^31-1 (2,147,483,647) (all numbers)	Int	2,147,483,648 to 2,147,483,647	-2147483648	Int32
Money	The currency data value is between -2^63 ( -922,337,203,685,477.5808) and 2^63-1 (+922,337,203,685,477.5807), which is accurate to 10 per thousand of the currency unit. The storage size is 8 bytes.	Single	-3.402823e38 to +3.402823e38	Single.minvalue	Currency
NChar	A maximum of 4,000 Unicode characters	String		Null	Stringfixedlength
ntext	The maximum length of a variable-length Unicode data is 230-1 (1,073,741,823) characters. The storage size is twice times the number of characters entered (in bytes).	String		Null	String
Numeric	When using maximum precision, valid values are from-10^38 +1 to 10^38-1	Decimal	-79,228,162,514,264,337,593,543,950,335 to 79,228,162,514,264,337,593,543,950,335	Decimal.minvalue	Decimal
nvarchar	A variable-length Unicode character data that contains n characters. The value of n must be between 1 and 4,000.	String		Null	String
Real	Floating-point numeric data from 3.40E + 38 to 3.40E + 38. The storage size is 4 bytes.	Single	-3.402823e38 to +3.402823e38	Single.minvalue	Single
smalldatetime	The date from January 1, 1900 to June 6, 2079 (each value requires 4 bytes of storage space).	Datetime	January 1, 01 00:00:00.0000000 to December 31, 9999 23:59:59.9999999	1900-01-01 0:00:00	Datetime
smallint	Integer data from -2^15 (-32,768) to 2^15-1 (32,767). The storage size is 2 bytes.	Int16	-32768 to 32767	Int16.minvalue	Int16
SmallMoney	The currency data value is between -214,748.3648 and +214.748,3647 and is accurate to 10 per thousand of the currency unit. The storage size is 4 bytes.	Single	-3.402823e38 to +3.402823e38	Single.minvalue	Currency
sql_variant	Large data types are not supported in SQL Server 2000 text, ntext, image, timestamp, other types are supported	Object		Null	Object
Text	The maximum length of a variable-length non-Unicode data in a server code page is 231-1 (2,147,483,647) characters. When the server code page uses double-byte characters, the storage is still 2,147,483,647 bytes. The storage size may be less than 2,147,483,647 bytes (depending on the string).	String		Null	Ansistring
Timestamp	Timestamp This data type shows the automatically generated binary number, ensuring that these numbers are unique in the database. Timestamp is generally used as a mechanism for adding a version stamp to a table row. The storage size is 8 bytes.	Byte[]		Null	Binary
tinyint	Integer data from 0 to 255. The storage size is 1 bytes.	Byte	0 to 255	Byte.minvalue	Byte
uniqueidentifier	Stores a 16-byte binary value that uses the same value as the globally unique identifier (GUID). A GUID is a unique binary number, and no two computers in the world will generate duplicate GUID values. GUIDs are primarily used to assign identifiers that must be unique in a network with multiple nodes and multiple computers.	Guid		Guid.Empty	Guid
varbinary	N bytes Variable-length binary data. n must be from 1 to 8,000. The size of the storage space is the actual input data length + 4 bytes instead of n bytes. The data entered may be 0 bytes in length.	Byte[]		Null	Binary
varchar	Variable-length, non-Unicode character data with a length of n bytes. n must be a numeric value between 1 and 8,000. Storage size is the actual length of bytes of input data, not n bytes. The input data character length can be zero.	String

Functions that convert SQL types to C # types

/// <summary>///data types in the database and in C # from what to ask/// </summary>/// <param name= "type" ></param>/// <returns></returns>Private stringChangetocsharptype (stringtype) {    stringReval =string. Empty;Switch(type. ToLower ()) { Case "int": Reval ="Int32"; Break; Case "text": Reval ="String"; Break; Case "bigint": Reval ="Int64"; Break; Case "binary": Reval ="system.byte[]"; Break; Case "bit": Reval ="Boolean"; Break; Case "Char": Reval ="String"; Break; Case "datetime": Reval ="System.DateTime"; Break; Case "decimal": Reval ="System.Decimal"; Break; Case "float": Reval ="System.Double"; Break; Case "Image": Reval ="system.byte[]"; Break; Case " Money": Reval ="System.Decimal"; Break; Case "nchar": Reval ="String"; Break; Case "ntext": Reval ="String"; Break; Case "Numeric": Reval ="System.Decimal"; Break; Case "nvarchar": Reval ="String"; Break; Case "Real": Reval ="System.Single"; Break; Case "smalldatetime": Reval ="System.DateTime"; Break; Case "smallint": Reval ="Int16"; Break; Case "smallmoney": Reval ="System.Decimal"; Break; Case "timestamp": Reval ="System.DateTime"; Break; Case "tinyint": Reval ="System.Byte"; Break; Case "uniqueidentifier": Reval ="System.Guid"; Break; Case "varbinary": Reval ="system.byte[]"; Break; Case "varchar": Reval ="String"; Break; Case "Variant": Reval ="Object"; Break;default: Reval ="String"; Break; } returnReval;}/*how to ask Hovertree.com*/

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The correspondence between SQL Server and data types in C #