Your first error-handling script
You realized your products table doesn't have any constraint to check the data stored in its stock column. It makes sense that stock is always greater than or equal to 0.
For some reason, there is a mistake in the following row. The stock is -1!
| product_id | product_name | stock | price |
|------------|--------------|-------|-------|
| 6 | Trek Neko+ | -1 | 2799 |
You want to prepare a script adding a constraint to the products table, so that only stocks greater than or equal to 0 are allowed.
If you add this constraint that only allows stocks greater than or equal to 0, the execution will fail because there is one row where the stock equals -1.
How can you prepare the script?
Cet exercice fait partie du cours
Transactions and Error Handling in SQL Server
Instructions
- Surround the constraint with a
TRYblock. - Add the constraint to the
productstable. - Surround the error message with a
CATCHblock.
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
-- Set up the TRY block
BEGIN ___
-- Add the constraint
ALTER TABLE ___
ADD CONSTRAINT CHK_Stock CHECK (stock >= 0);
___ ___
-- Set up the CATCH block
___ ___
SELECT 'An error occurred!';
END ___