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The number of variables in a FETCH statement should match the number of columns in the cursor
Description
The FETCH statement in SQL Server should have the same number of variables as the number of columns in the cursor. This ensures that the correct data is retrieved from the database. If the number of variables does not match the number of columns, then the query will fail. This rule helps to ensure that the data being retrieved is accurate and complete.
Key Benefits
- Ensures Data Accuracy: The FETCH statement ensures that the number of variables and columns in the cursor match, thus guaranteeing data accuracy.
- Reduces Development Time: By matching the number of variables and columns in the cursor, the FETCH statement reduces the development time associated with coding.
- Prevents Data Loss: The FETCH statement prevents data loss by ensuring that all data is retrieved from the cursor.
- Improves Performance: By matching the number of variables and columns in the cursor, the FETCH statement improves query performance.
Non-compliant Code Example
DECLARE @FirstName varchar(50);
DECLARE contact_cursor CURSOR FOR
SELECT LastName, FirstName FROM Person.Person
OPEN contact_cursor;
FETCH NEXT FROM contact_cursor
INTO @FirstName; --Non compliant code (Number of variable in Fetch statement is not matching with number of columns in the cursor)
Compliant Code Example
DECLARE @LastName varchar(50), @FirstName varchar(50);
DECLARE contact_cursor CURSOR FOR
SELECT LastName, FirstName FROM Person.Person
OPEN contact_cursor;
FETCH NEXT FROM contact_cursor
INTO @LastName, @FirstName; --Compliant code (Number of variable in Fetch statement is matching with number of columns in the cursor)