How to check if sp_rename is done successfully? - sql-server

Question

I am running the following query:
SELECT * INTO dbo.2015_10_2_cs FROM dbo.2015_10_2
IF NOT EXISTS
(SELECT type FROM sys.indexes WHERE object_id = object_id('dbo.2015_10_2_cs')
AND NAME ='cci' AND type = 5)
BEGIN
CREATE CLUSTERED COLUMNSTORE INDEX cci
ON dbo.2015_10_2_cs
DROP TABLE dbo.2015_10_2
EXEC sp_rename "dbo.2015_10_2_cs" , "dbo.2015_10_2"
END
and I want to make sure that the part where I am renaming the table dbo.2015_10_2_cs to dbo.2015_10_2 is done successfully (without losing any data).
The step inside the loop should be surrounded with SQL transaction to keep the process safe and reliable (in case if any step will fail).
Could anyone help with this? Thanks in advance.

Answer 1

EXEC sp_rename "dbo.2015_10_2_cs" , "dbo.2015_10_2"
This will not do what you expect. The new table will be named [dbo].[dbo.2015_10_2] if you specify the schema name in the new table name. Renamed tables are implicitly in the existing table's schema since one must use ALTER SCHEMA instead of sp_rename to move an object between schemas.
There are a number of other problems with your script. Because the table name starts with a number, it doesn't conform to regular identifier naming rules and must be enclosed in square brackets or double quotes. The literal parameters passed to sp_rename should be single quotes. You can also check to stored procedure return code to ascertain success or failure. The example below performs these tasks in a transaction with structured error handling.
DECLARE #rc int;
BEGIN TRY
BEGIN TRAN;
IF NOT EXISTS
(SELECT type FROM sys.indexes WHERE object_id = object_id(N'dbo.2015_10_2_cs')
AND NAME ='cci' AND type = 5)
BEGIN
CREATE CLUSTERED COLUMNSTORE INDEX cci
ON dbo.[2015_10_2_cs];
DROP TABLE dbo.[2015_10_2];
EXEC #rc = sp_rename 'dbo.[2015_10_2_cs]' , '2015_10_2';
IF #rc <> 0
BEGIN
RAISERROR('sp_rename returned return code %d',16,1);
END;
END;
COMMIT;
END TRY
BEGIN CATCH
IF ##TRANCOUNT > 0 ROLLBACK;
THROW;
END CATCH;

Answer 2

You can use an EXISTS checking for the tablename and schema.
IF NOT EXISTS (SELECT 'table does not exist' FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = N'2015_10_2'AND TABLE_SCHEMA = 'dbo')
BEGIN
RAISERROR('The table doesn''t exist!!!!', 16, 1)
END
sp_rename won't make you lose table contents, it will just change the table reference name and update all it's contraints and indexes references. It will also raise an error if the table to rename does not exist. Maybe what you want is to wrap your process in a transaction and rollback if something fails.
EDIT:
For basic transaction handling you can use the following. Please read the documentation for using transaction, it might take a while to know how it works correctly.
IF OBJECT_ID('tempdb..#Test') IS NOT NULL
DROP TABLE #Test
CREATE TABLE #Test (Number INT)
SELECT AmountRecords = COUNT(1) FROM #Test -- AmountRecords = 0
BEGIN TRY
BEGIN TRANSACTION
-- Do your statements here
INSERT INTO #Test (Number)
VALUES (1)
DECLARE #errorVariable INT = CONVERT(INT, 'NotAnInteger!!') -- Example of error: can't convert
COMMIT
END TRY
BEGIN CATCH -- If something goes wrong
IF ##TRANCOUNT > 0 -- ... and transaction is still open
ROLLBACK -- Revert statements from the BEGIN TRANSACTION onwards
END CATCH
SELECT AmountRecords = COUNT(1) FROM #Test -- AmountRecords = 0 (the transaction was rolled back and the INSERT reverted)
Basically you use BEGIN TRANSACTION to initiate a restore point to go back to if something fails. Then use a COMMIT once you know everything is OK (from that point onwards, other users will see the changes and modifications will be persisted). If something fails (you need TRY/CATCH block to handle errors) you can issue a ROLLBACK to revert your changes.