Rename column SQL Server 2008

Before you rename

Prior to renaming test this action in a non-production environment. Assess possible dependencies:

SELECT * FROM sys.sql_expression_dependencies 
WHERE referenced_entity_name = 'OldColumnName';


Dependencies and interrupts

Use caution! Changing column names can disrupt stored procedures, triggers, and views. Test and update related objects:

-- Example: Update a View
ALTER VIEW ViewName
AS
SELECT ..., newColumn AS OldColumnName ...
FROM table;


Ensure your desired new column name doesn’t clash with existing names within the table. Rerun a check count with:

-- Check if it exists already, you might end up naming your kid after their sibling
SELECT COUNT(1) FROM table
WHERE COLUMN_NAME = 'newColumn'


Schema naming

Include schemas to avoid confusion when renaming:

EXEC sp_rename 'schema.table.column', 'newColumn', 'COLUMN';


In prepending the schema name, ambiguity dissipates like water on a hot pan – sizzled away!

Safeguards

Initiate transactions for robust error handling:

BEGIN TRANSACTION;
EXEC sp_rename 'table.column', 'newColumn', 'COLUMN';
-- Fool-proofing area: SELECT, Test scripts, etc.
COMMIT TRANSACTION;


It's like a digital Indiana Jones adventure – untouched, hidden treasures revealed, but rollbacks possible!

Renaming using GUI

For those who prefer to swap command lines for clicks, SQL Server Management Studio (SSMS) has your back:

• Double-click slowly on the column in the Object Explorer.
• Right-click the column, and click "Rename" if you've had a longer coffee break.

Bear in mind, the UI approach is often best suited for one-off changes.

Renaming multiple columns

In a bid to embrace laziness – or efficiency – here's how you can rename multiple columns in SSMS:

1. Hit right-click on the table in Object Explorer.
2. Select "Design".
3. Alter column names directly in the grid ala Excel.

Remember, don’t leave without saving the changes. Database columns are not as forgiving as Word documents.

The 'Script As' case

When using Script As options in SSMS for automation, confirm scripts meet your expectations before letting it loose:

-- CTRL+C, CTRL+V, did I do it right? Test before sending it off to space!
EXEC sp_rename 'table.column', 'newColumn', 'COLUMN';


Scripted renaming

Lastly, use system functions to validate column existence:

IF EXISTS(SELECT 1 FROM sys.columns 
          WHERE Name = N'oldColumnName' 
          AND Object_ID = Object_ID(N'tableName'))
AND NOT EXISTS(SELECT 1 FROM sys.columns 
               WHERE Name = N'newColumnName' 
               AND Object_ID = Object_ID(N'tableName'))
BEGIN
    -- This is it, moment of truth!
    EXEC sp_rename 'tableName.oldColumnName', 'newColumnName', 'COLUMN';
END


This validation checks the existence of the old column and verifies that the new name isn’t already in use, therefore avoiding a potentially embarrassing name clash.