Restore Verify Only Loop with Update - sql

Question

I'm running a Restore Verify Only loop through a table, but I need it to UPDATE a field in that table if it's successful. Here is my code:
DECLARE #Path NVARCHAR(max)
DECLARE #DatabaseName NVARCHAR(100)
DECLARE #NSql NVARCHAR(1000)
DECLARE #Update NVARCHAR(200)
DECLARE #DB_Text NVARCHAR(50)= 'Backup has been confirmed for'
BEGIN
DECLARE
#DatabaseId INT = 1,
#NumberOfDBs INT
SELECT #NumberOfDBs= COUNT(*) FROM dbo.RestoreVerifyDatabases
WHILE #DatabaseId<= #NumberOfDBs
BEGIN
SELECT * FROM dbo.RestoreVerifyDatabases WHERE DatabaseId= #DatabaseId
SET #DatabaseId = #DatabaseId + 1
END
SET #Path = (SELECT LastBackupFileName FROM RestoreVerifyDatabases WHERE DatabaseId =
#DatabaseId)
SET #DatabaseName = (SELECT DatabaseName FROM RestoreVerifyDatabases WHERE DatabaseId =
#DatabaseId)
SET #NSql = N'SELECT LastBackupFileName
FROM RestoreVerifyDatabases
WHERE DatabaseName = #DatabaseName
AND DatabaseId = #DatabaseId'
EXEC sp_executesql #NSql
IF #DatabaseId IS NULL
BEGIN
RAISERROR(N'Verify failed. Backup information for database N''#DatabaseName'' not
found.', 16, 1)
END
RESTORE VERIFYONLY
FROM #Path
WITH FILE = #DatabaseId, checksum
SET #Update= N'UPDATE RestoreVerifyDatabases
SET Confirmed = #DB_Text + #DatabaseName
WHERE DatabaseID = #DatabaseId'
EXEC sp_executesql #Update
END
The looping and calling of Restore Verify Only works fine but the UPDATE is not getting called. Please help.

Answer 1

There's a few things wrong with your code as far as I can see. As my comment indicated, you run a loop over the #databaseID, and then immediately increase the id with 1 within the loop.
This means your #databaseId simply will increase until it reaches the maximum value of the id, and then exits the loop. The rest of your code will then execute once (only for that ID).
That happens here in your code:
SELECT #NumberOfDBs= COUNT(*) FROM dbo.RestoreVerifyDatabases
WHILE #DatabaseId<= #NumberOfDBs
BEGIN
SELECT * FROM dbo.RestoreVerifyDatabases WHERE DatabaseId= #DatabaseId
SET #DatabaseId = #DatabaseId + 1
END
-- Bunch of other code
So #databaseID goes from 1 to 50 (just a random number) within that loop, then exists with a value of 50. None of the underlying code ever gets to see any value other than 50.
To fix that, the code should look like this:
SELECT #NumberOfDBs= COUNT(*) FROM dbo.RestoreVerifyDatabases
WHILE #DatabaseId<= #NumberOfDBs
BEGIN
SELECT * FROM dbo.RestoreVerifyDatabases WHERE DatabaseId= #DatabaseId
-- Bunch of other code
SET #DatabaseId = #DatabaseId + 1
END
This would ensure the "bunch of other code" processes #databaseid = 1, then processes #databaseid = 2, etc. until #databaseid = 50.
You can also remove this line:
SELECT * FROM dbo.RestoreVerifyDatabases WHERE DatabaseId= #DatabaseId
I suspect you have it for debugging purposes, but it doesn't really do anything.
These lines can be simplified:
SET #Path = (SELECT LastBackupFileName FROM RestoreVerifyDatabases WHERE DatabaseId =
#DatabaseId)
SET #DatabaseName = (SELECT DatabaseName FROM RestoreVerifyDatabases WHERE DatabaseId =
#DatabaseId)
as:
SELECT #Path = LastBackupFileName, #DatabaseName = DatabaseName FROM RestoreVerifyDatabases WHERE DatabaseId = #DatabaseId
You also have a RAISEERROR. I suspect that is because you do a count(*), rather than selecting actually existing #databaseids. This works in an ideal scenario, where databases never get deleted. In the reasl world, though, you'd go from databaseid 1 to 5, because 2, 3, and 4 were removed. Your count will still be 50 databases, but you'd miss all databases with ids above the count due to these gaps. You'd be trying to process the databaseid that no longer exists, and miss the ones with an id > 50.
You could instead write your loop to do something like the following:
SELECT #DatabaseID = MIN(DatabaseID) FROM dbo.RestoreVerifyDatabases
WHILE #datbaseID IS NOT NULL
BEGIN
-- Do stuff
SELECT #DatabaseID = MIN(DatabaseID) FROM dbo.RestoreVerifyDatabases WHERE databaseID > #databaseID
END
Finally, your dynamic code isn't working. You are adding literal text rather than the value of the parameters. If I print the value of #Update at the end, it shows as:
UPDATE RestoreVerifyDatabases
SET Confirmed = #DB_Text + #DatabaseName
WHERE DatabaseID = #DatabaseId
Your code should be something like:
SET #Update= CONCAT('UPDATE RestoreVerifyDatabases SET Confirmed = ''', #DB_Text, ' ', #DatabaseName, ''' WHERE DatabaseID = ', #DatabaseId)
Which outputs:
UPDATE RestoreVerifyDatabases SET Confirmed = 'Backup has been confirmed for Last' WHERE DatabaseID = 2