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This article is to share with you what are the nine common statements of sql in the database. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

I. Foundation

1. Description: create a database

CREATE DATABASE database-name

2. Description: delete the database

Drop database dbname

3. Description: backup sql server

-create a device for backing up data

USE master

EXEC sp_addumpdevice 'disk',' testBack','c:\ mssql7backup\ MyNwind_1.dat'

-start backup

BACKUP DATABASE pubs TO testBack

4. Description: create a new table

Create table tabname (col1 type1 [not null] [primary key], col2 type2 [not null],..)

Create a new table based on an existing table:

A:create table tab_new like tab_old (create a new table using the old table)

B:create table tab_new as select col1,col2... From tab_old definition only

5. Description: delete the new table

Drop table tabname

6. Description: add a column

Alter table tabname add column col type

Note: columns cannot be deleted after they are added. The data type cannot be changed after the column is added in DB2, and the only thing that can change is to increase the length of the varchar type.

7. Description: add primary key: Alter table tabname add primary key (col)

Description: delete primary key: Alter table tabname drop primary key (col)

8. Description: create an index: create [unique] index idxname on tabname (col … (.)

Delete index: drop index idxname

Note: the index is immutable and must be deleted and rebuilt if you want to change it.

9. Description: create view: create view viewname as select statement

Delete View: drop view viewname

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