MAGER MULUK: SQL Tutorial Part3

SQL - Data Types

SQL data type is an attribute that specifies type of data of any object. Each column, variable and expression has related data type in SQL.

You would use these data types while creating your tables. You would choose a particular data type for a table column based on your requirement.

SQL Server offers six categories of data types for your use:

Exact Numeric Data Types:

DATA TYPE FROM    TO

bigint -9,223,372,036,854,775,808 9,223,372,036,854,775,807

int -2,147,483,648 2,147,483,647

smallint -32,768 32,767

tinyint 0     255

bit            0        1

decimal             -10^38 +1       10^38 .1

numeric -10^38 +1       10^38 .1

money -922,337,203,685,477.5808 +922,337,203,685,477.5807

smallmoney -214,748.3648    +214,748.3647

Approximate Numeric Data Types:
DATA TYPE    FROM TO

float    -1.79E + 308 1.79E + 308

real -3.40E + 38 3.40E + 38

Date and Time Data Types:

DATA TYPE FROM TO

datetime    Jan 1, 1753 Dec 31, 9999

smalldatetime    Jan 1, 1900 Jun 6, 2079

date Stores a date like June 30, 1991

time Stores a time of day like 12:30 P.M.

Character Strings Data Types:
DATA TYPE FROM       TO

char char Maximum length of 8,000
         characters.( Fixed length non-
   Unicode characters)

varchar varchar    Maximum of 8,000
   characters.(Variable-length non-
                 Unicode data).

varchar(max)    varchar(max)       Maximum length of 231characters,
                 Variable-length non-Unicode data
                 SQL Server 2005 only).

text             text               Variable-length non-Unicode data
   with a maximum length of
                 2,147,483,647 characters.

Unicode Character Strings Data Types:
DATA TYPE Description

nchar Maximum length of 4,000 characters.( Fixed length Unicode)

nvarchar    Maximum length of 4,000 characters.(Variable length Unicode)

nvarchar(max) Maximum length of 231characters (SQL Server 2005 only).(
     Variable length Unicode)

ntext Maximum length of 1,073,741,823 characters. ( Variable length
     Unicode )

Binary Data Types:

DATA TYPE Description

binary Maximum length of 8,000 bytes(Fixed-length binary data )

varbinary Maximum length of 8,000 bytes.(Variable length binary data)

varbinary(max)    Maximum length of 231 bytes (SQL Server 2005 only). ( Variable
     length Binary data)

image      Maximum length of 2,147,483,647 bytes. ( Variable length Binary
     Data)

Misc Data Types:

DATA TYPE Description

sql_variant Stores values of various SQL Server-supported data types, except
    text, ntext, and timestamp.

timestamp    Stores a database-wide unique number that gets updated every
   time a row gets updated

uniqueidentifier     Stores a globally unique identifier (GUID)

xml    Stores XML data. You can store xml instances in a column or a
   variable (SQL Server 2005 only).

cursor    Reference to a cursor object

table    Stores a result set for later processing

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Sunday, September 25, 2011

SQL Tutorial Part3