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1. Delete operation
(1) Delete the entire table does not retain any information
drop table table name
such as:
drop table student
Data (2) deleting the table, the table retention structure
truncate (table) table
, such as:
truncate (table) student
Or
delete from table name
such as:
delete from student
delete from student where age < 21
And delete the difference 2.truncate
| rollback | WHERE and use | Reset Index | return value | |
|---|---|---|---|---|
| truncate | NO | NO | YES | NO |
| delete | YES | YES | NO | The number of rows deleted |
3. Notes
For table increment field, delete insert operation after the fault should pay attention to the problem from growing.
After using the delete all data into a new data you want to maintain increment from the beginning, we need to use
delete from student where ture.
Otherwise, the next index will be removed before the start of the last index increment.
Use truncate table to delete data will automatically reset the index increment of 1.
Reference: https://www.cnblogs.com/shuaiandjun/p/6042600.html
https://www.cnblogs.com/fcc-123/p/10672604.html