SQL Server vs. C# Data Types

Question

Is there a cross reference available between the SQL Server data types and C# data types? SQL Server appears to have many more 'primitive' data types than C#.

Thanks

Answer 1

Hi, Paolo,

       I hope the following information will be helpful. Please click here to get the original doc.

 

SQL Server 2008 Books Online

Mapping CLR Parameter Data

The following table lists Microsoft SQL Server data types, their equivalents in the common language runtime (CLR) for SQL Server in the System.Data.SqlTypes namespace, and their native CLR equivalents in the Microsoft .NET Framework.

SQL Server data type	CLR data type (SQL Server)	CLR data type (.NET Framework)
bigint	SqlInt64	Int64, Nullable<Int64>
binary	SqlBytes, SqlBinary	Byte[]
bit	SqlBoolean	Boolean, Nullable<Boolean>
char	None	None
cursor	None	None
date	SqlDateTime	DateTime, Nullable<DateTime>
datetime	SqlDateTime	DateTime, Nullable<DateTime>
datetime2	SqlDateTime	DateTime, Nullable<DateTime>
DATETIMEOFFSET	None	DateTimeOffset, Nullable<DateTimeOffset>
decimal	SqlDecimal	Decimal, Nullable<Decimal>
float	SqlDouble	Double, Nullable<Double>
image	None	None
int	SqlInt32	Int32, Nullable<Int32>
money	SqlMoney	Decimal, Nullable<Decimal>
nchar	SqlChars, SqlString	String, Char[]
ntext	None	None
numeric	SqlDecimal	Decimal, Nullable<Decimal>
nvarchar	SqlChars, SqlString SQLChars is a better match for data transfer and access, and SQLString is a better match for performing String operations.	String, Char[]
nvarchar(1), nchar(1)	SqlChars, SqlString	Char, String, Char[], Nullable<char>
real	SqlSingle	Single, Nullable<Single>
rowversion	None	Byte[]
smallint	SqlInt16	Int16, Nullable<Int16>
smallmoney	SqlMoney	Decimal, Nullable<Decimal>
sql_variant	None	Object
table	None	None
text	None	None
time	TimeSpan	TimeSpan, Nullable<TimeSpan>
timestamp	None	None
tinyint	SqlByte	Byte, Nullable<Byte>
uniqueidentifier	SqlGuid	Guid, Nullable<Guid>
User-defined type(UDT)	None	The same class that is bound to the user-defined type in the same assembly or a dependent assembly.
varbinary	SqlBytes, SqlBinary	Byte[]
varbinary(1), binary(1)	SqlBytes, SqlBinary	byte, Byte[], Nullable<byte>
varchar	None	None
xml	SqlXml	None

Answer 2

Gary: just what I was looking for. Many thanks.

Answer 3

All -- This given mapping matrix is nice. However, it could be better. For example, when actually writing C# code, instead of "Int64" one should use "long", by convention and best-practice. The same goes for "float" and "int" and etc. That is what Microsoft has recommended in the past, and I guess they probably still recommend it. The matrix ought to reflect such conventions. Regardless, it is a decent matrix. HTH. Thanks. -- Mark Kamoski

Answer 4

Since we don't have a mapping between varchar and nvarchar, should we use nvarchar if we want to use EF?

Also, for smallint should I use Int16?

Thanks.

---

For every expert, there is an equal and opposite expert. - Becker's Law


My blog