Question

Simple question here.

Context: A Transact-SQL table with an int primary key, and a name that also must be unqiue (even though it’s not a primary key). Let’s say:

TableID INT,
TableName NVARCHAR(50)

I’m adding a new rows to this able through a stored procedure (and, thus, specifying TableName with a parameter).

Question: What’s the best/simplest way to verify if the provided TableName parameter already exist in the table, and to prevent the add of a new row if it’s the case?

Is possible to do this directly within my AddNewRow stored procedure?

Answer 1

If you’re using SQL Server 2008 then you could use a MERGE statement in your sproc:

MERGE INTO YourTable AS target
USING (VALUES (@tableName)) AS source (TableName)
    ON target.TableName = source.TableName
WHEN NOT MATCHED THEN
    INSERT (TableName) VALUES (TableName)

You should still ensure that the TableName column has a UNIQUE constraint.