DAL与数据库类型的对应关系

MSSQL Server类型	DbType类型	C#类型		MySql类型	DbType类型	C#类型
bit	Boolean	bool		bit(1)	Boolean	bool
tinyint	Byte	byte		bit	UInt64	ulong
smallint	Int16	short		tinyint(1)	Boolean	bool
int	Int32	int		tinyint	Byte	byte
bigint	Int64	long		smallint	Short	short
real	Single	float		int	Int32	int
float	Double	double		bigint	Int64	long
money	Decimal	decimal		decimal	Currency	decimal
numeric	Decimal	decimal		double	Double	double
decimal	Currency	decimal		float	Single	float
smallmoney	Currency	decimal		char(1)	AnsiStringFixedLength	char
date	Date	DateTime		char	AnsiStringFixedLength	string
time	Time	TimeSpan		varchar	AnsiString	string
datetime	DateTime	DateTime		date	DateTime	DateTime
smalldatetime	DateTime	DateTime		datetime	DateTime	DateTime
datetime2	DateTime	DateTime		time	Time	TimeSpan
datetimeoffset	DateTimeOffset	DateTime		timestamp	DateTime	DateTime
timestamp	Binary	byte[]		year	Int16	short
char(1)	AnsiStringFixedLength	char		binary	Binary	byte[]
char	AnsiStringFixedLength	string		text	String	string
varchar	AnsiString	string
nchar	StringFixedLength	char
nvarchar	String	string
text	String	string
ntext	String	string
image	Binary	byte[]
binary	Binary	byte[]
uniqueidentifier	Guid	Guid
image	Binary	byte[]
sql_variant	Object	object
xml	Xml	string