To better design the database, reorganize the SQL Server data type

In the normal development process, in the design of data, often encountered the problem of data type selection, in order to faster, more appropriate to choose the correct data type, so here is a summary.

Classification	SQL Server Data type	C# Data type	Describe	Application Scenarios
Characters and strings	CHAR (n)	String	Fixed-length string with a maximum of 8,000 characters
	NCHAR (n)	String	Fixed-length Unicode data with a maximum of 4,000 characters
	VARCHAR (n)	String	Variable-length string with a maximum of 8,000 characters	"Common", which represents a string and does not contain Chinese.
	nvarchar (n)	String	Variable-length Unicode data with a maximum of 4,000 characters	"Common", which represents a string that contains Chinese.
	varchar (max)	String	Variable-length string with a maximum of 1,073,741,824 characters	"Common", with varchar (n), stores more characters.
	nvarchar (max)	String	Variable-length Unicode data with a maximum of 536,870,912 characters	"Common", with nvarchar (n), stores more characters.
	Text	String	Variable-length string, up to 2GB
	ntext	String	Variable-length UNICDE data, up to 2GB
Integer	Bit	bool	Represents 0,1 or null	A field that is typically used to indicate whether or not two states are in use.
	tinyint	Byte	An integer representing the 0~255 range	Commonly used to represent states or types, and in C # you can define enumerations to represent them.
	smallint	Short	An integer representing the range -2^15 to 2^15-1
	Int	Int	An integer representing the range -2^31 to 2^31-1	"Common", representing integers, or self-increasing primary key IDs
	bigint	Long	An integer representing the range -2^63 to 2^63-1	"Common", which represents integers, represents a larger range.
Exact number	Float	Single	Represents a 32-bit floating point number with a precision of 7 bits	Common, the initialization suffix uses F or F, which is generally used to denote the amount.
	Double	Double	Represents a 64-bit floating point number with a precision of 15 to 16 bits	"Common", initialize suffix using D or D
	Decimal	Decimal	Represents a 128-bit floating point number with a precision of 28 to 29 bits	Initialize suffix using m or m
Currency	SmallMoney	Decimal	Ditto
	Money	Decimal	Ditto
Date Time	smalldatetime	Datetime	Represents a precision of 1 minutes from January 1, 1900 to June 6, 2079.
	Datetime	Datetime	From January 1, 1753 to December 31, 9999, the accuracy is 100 nanoseconds.	"Common", which represents time.
Binary	Binary	Byte[]	Represents fixed-length binary data with a maximum of 8,000 characters
	varbinary (n)	Byte[]	Represents a variable-length binary data that stores up to 8,000 characters
	varbinary (max)	Byte[]	Represents variable-length binary data with up to 2GB of storage	"Common", typically used to store compressed data.
	Image	Byte[]	Represents variable-length binary data with up to 2GB of storage
Mark	Timestamp	N/A	Timestamp, the data type is unique in every table! When one record in the table changes, the timestamp field of the record is automatically updated
	uniqueidentifier	Guid	Store Global Identifiers (GUIDs)	Commonly used to represent a primary key, a unique identifier.
... ...

Reference article:

Http://www.cnblogs.com/mcgrady/p/3840812.html

Http://blog.sina.com.cn/s/blog_49998558010009jy.html

Http://www.w3school.com.cn/sql/sql_datatypes.asp

Http://www.studyofnet.com/news/214.html

To better design the database, reorganize the SQL Server data type