Data types in SQL Server -2008:



Number Data Type: This data type allows us to enter numeric values i.e. either integer (or) decimal values
Integer: This data type allows us to enter only integer values i.e. either positive(+ve) numbers (or) Negative (-ve) numbers
This data type further divided into 4 types
1. Tiny int       → 1 byte
2. Small int     → 2 bytes
3. int               → 4 bytes
4. Long int     → 8 bytes
These data types occupies the memory in 1, 2, 4, 8 bytes respectively
These data types allows the column values like Student Roll no, Employee Id etc,
Ex: EmpId int
EmpId represent column name
Int represent data type (4 bytes)
 
Decimal Data type:
   This data type allows us to enter only Decimal values such as employee salary, student average marks etc., These data type is again divided into two types
NUMERIC (p, s)
DECILMAL (p, s)
Here ‘p’ represent precision & ‘s’ represent Scale
EX: ESal NUMERIC (9, 1)
Here ESAL column name
Numeric data type
9-p
1-s
Note: Numeric & Decimal data type are exactly same
 
Alphabet data type:
This data type allows us to enter character values such as student names, employee names etc.,
This data type of further divided into two types
1.     Char [size]
2.     Varchar [size]

Char [size]:
This data type allows us to enter only alphabets and it allows maximum of 1-4000 bytes
It always allocates the memory in a static fashion
EX: Sno char [9]
Sno represents student number, char represents data type, 9 represents size
Varchar [size]:
This data type allows us to enter alphabets, alpha numeric & numeric values also
This data type allows maximum of 1-8000 bytes
It always allocates the memory in Dynamic manner

Date data type:
This data type allows to enter date values such as employee joining date, Account opening date etc.,
The default date format in SQL Server is yyyy-mm-dd
Ex: 1987-12-10

Time stamp:
This data type allows us to enter both date & time
The default format of time stamp data type is yyyy-mm-Degree
Ex: yyyy-mm-dd-hh:mm:ss
1987-12-10 12:49:09

Mislenious data type:
Image Data type: This data type allows us to enter any picture (or) photos, clipping, sounds etc

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