问题描述
我想避免数据重复,假设我有一个表名为Schema_tbl,其中包含2个coloums
Schema_tbl列是:
tblNames | primaryKeysCol
数据:
tblCustomer | cmpid
tblCustomer | brchid
tblCustomer | pkid
- 重复值 -
tblCustomer | cmpid
现在如何制作一个复合键,避免重复键复制键复制键复制键
我尝试过的事情:
只有开发的模式我才能解决复合键会被应用但是如何
I want to avoid duplication of data suppose i have a table name Schema_tbl that holds 2 coloums
Schema_tbl columns are :
tblNames | primaryKeysCol
data:
tblCustomer | cmpid
tblCustomer | brchid
tblCustomer | pkid
--duplicated values --
tblCustomer | cmpid
now how to make a composite key that avoids the duplicated of data in primary key coloumns agains composite key
What I have tried:
NOTHING ONLY DEVELOPED SCHEMA I GOOGLED BUT FOUND SOLUTION THAT COMPOSITE KEYS WILL BE APPLIED BUT HOW TO
推荐答案
ALTER TABLE Schema_tbl
ADD CONSTRAINT pk_myConstraint PRIMARY KEY (tblNames,primaryKeysCol)
希望,它有帮助:)
Hope, it helps :)
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