如何删除和更新sql中的主键 [英] how to remove and update primary keys in sql

问题描述

我想在从表中删除后添加主键。

I want to add primary key once it is removing from table.

alter table tbl_item_rate alter column c_item_code varchar(25)

此查询正在执行但是错误抛出..



错误ID

this query am executing but error throwing..

error id that

Msg 5074, Level 16, State 1, Line 1
The object 'PK_tbl_item_rate' is dependent on column 'c_item_code'.
Msg 4922, Level 16, State 9, Line 1
ALTER TABLE ALTER COLUMN c_item_code failed because one or more objects access this column.

推荐答案

因为它是主键，所以你无法改变它 - SQL依赖于PK来进行索引。

要更改主键列的类型，你需要删除主键，更改表格，然后重新建立PK：

Because it's the primary key, you can't change it - SQL relies on the PK for it's indexing.
To change the type of teh primary key column, you have to remove teh primary key, change your table, and the re-establish the PK:

ALTER TABLE tbl_item_rate
DROP CONSTRAINT PK_tbl_item_rate

ALTER TABLE tbl_item_rate 
ALTER COLUMN c_item_code varchar(25)

ALTER TABLE tbl_item_rate
ADD CONSTRAINT PK_tbl_item_rate PRIMARY KEY (c_item_code)

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