Constraint in DB table for SQL and oracle

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Hi,

I have a scenario where i should restrict the data to be inserted in table where one column with the same value and other column with null . for ex :

I have the below table, i want to restrict the 3rd row to be inserted where Name column with the value A which exists already and Salary as Null. I want to write a constraint for the same in Database. Can some once pls help

Id Name age salary
1 A 30 NULL
2 B 32 5000
3 A 30 NULL

What I have tried:

Thorugh code we can restrict the data to inserted with the values but through DB we would need it

Posted 29-Apr-21 18:16pm

User CP

Updated 29-Apr-21 23:42pm

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CHill60 · Answer 1 · 2021-04-29T23:42:00

Solution 1

It sounds like you need to set up a unique constraint. See Create Unique Constraints - SQL Server | Microsoft Docs[^] for SQL Server or Oracle Unique Constraint: Ensures Unique Data Contained in a Column[^] for Oracle

Posted 29-Apr-21 23:42pm

CHill60

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CHill60 30-Apr-21 7:07am

Should have added - don't forget to handle the exception that is raised when you try to add a duplicate row. Can't give more detail than that without knowing what language you use and how you insert the records