How to check in a stored proc if data is already present?

I have a stored proc like the following. It works on a table called
ProductType with only one field, called ProductTypeName.

DROP PROCEDURE IF EXISTS myDB.setProductType;
CREATE PROCEDURE myDB.`setProductType`(

IN ProductType VARCHAR(20))
BEGIN
INSERT INTO ProductType
(
ProductTypeName
)
VALUES
(
ProductTypeName );
END;

It works fine, but I would like to avoid duplicates. How can I make
the stored proc check if that ProductTypeName is already in the table,
and only insert it if it's not? Thanks.

Bruno Panetta <bpanetta@gmail.com> wrote in news:9ffbff93-5518-414e-a8dd-
5f8f3a8b3298@b40g2000prf.googlegroups.com:

> I have a stored proc like the following. It works on a table called
> ProductType with only one field, called ProductTypeName.
>
> DROP PROCEDURE IF EXISTS myDB.setProductType;
> CREATE PROCEDURE myDB.`setProductType`(
>
> IN ProductType VARCHAR(20))
> BEGIN
> INSERT INTO ProductType
> (
> ProductTypeName
> )
> VALUES
> (
> ProductTypeName );
> END;
>
> It works fine, but I would like to avoid duplicates. How can I make
> the stored proc check if that ProductTypeName is already in the table,
> and only insert it if it's not? Thanks.
>

Place a UNIQUE index on that column which will preclude duplicates.