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Difference between delete and truncate


Delete
Truncate
In Delete Query we can use Where Clause
In Truncate Query we can not use Where Clause
Syntax
DELETE FROM [Table_Name]
or
DELETE FROM [Table_Name] WHERE [Condition]

Syntax:
TRUNCATE TABLE [Table_Name]
Comparing the Delete is Slower than truncate Comparing the Truncate is faster than the delete query
In Delete Query we can delete single only or multiple rows by using where clause. In Truncate Query All the rows data truncated from table.
We can use triggers when delete query is executed . We can not use triggers when truncate query is executed.
Delete query is logs the data. Truncate can not log the data.
Delete query delete the data from table using row by row scenario. Truncate query truncate the data from table using page by page scenario.
Delete can not reset the identity value in a table. Truncate can reset the identity value in a table.
It does not claims the memory after delete operation is performed
Example:
Create table
CREATE TABLE TempStudent
(
FName varchar(100),
LName varchar(100)
)


Insert some dummy data
Insert into TempStudent(FName,LName) VALUES('Rakesh','Kalluri')
Go 1000
Check the memory used for this table.
exec sp_spaceused 'TempStudent'


Delete data from table
DELETE FROM TempStudent
Check the memory used for this table after delete
exec sp_spaceused 'TempStudent'
It claims the memory after truncate operation is performed
Example:
Create table
CREATE TABLE TempStudent
(
FName varchar(100),
LName varchar(100)
)


Insert some dummy data
Insert into TempStudent(FName,LName) VALUES('Rakesh','Kalluri')
Go 1000
Check the memory used for this table.
exec sp_spaceused 'TempStudent'


Truncate data from table
TRUNCATE TABLE TempStudent
Check the memory used for this table after truncate
exec sp_spaceused 'TempStudent'

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