MSSQL – Violation of UNIQUE KEY constraint

I’m getting this error message

IntegrityError: (2627, b"Violation of UNIQUE KEY constraint
‘XXXXX_TypeOfData_input_un’. Cannot insert duplicate key in object
‘XXXXX.TypeOfData_input’. The duplicate key value is (Processing Data,
Processing Data Name).DB-Lib error message 20018, severity
14:\nGeneral SQL Server error: Check messages from the SQL Server\n")

How to add unique constraint when insert?

My code

INSERT INTO XXXXX.TypeOfData_input (TypeName, DataName)
        VALUES (%(TypeName)s, %(DataName)s)

My usual code for postgresql

INSERT INTO XXXXX.TypeOfData_input (TypeName, DataName)
            VALUES (%(TypeName)s, %(DataName)s) ON CONFLICT (TypeName, DataName) DO UPDATE NOTHING

>Solution :

We can use a MERGE statement to insert only if the record doesn’t already exist.

MERGE INTO XXXXX.TypeOfData_input AS target
USING (VALUES (%(TypeName)s, %(DataName)s)) AS source (TypeName, DataName)
ON target.TypeName = source.TypeName AND target.DataName = source.DataName
WHEN NOT MATCHED THEN
    INSERT (TypeName, DataName)
    VALUES (source.TypeName, source.DataName);