Automatic database restore using DateTime functions in SQL Server

Scenario

I have to restore a production database to a development database on a weekly basis in order to refresh the environment. Currently, I’m doing this process manually. Is there any way to script this out so it can be automated?  Check out this tip to learn more.

Solution

If you take full backups using SQL Server maintenance plans and let SQL Server use the default naming convention, you have probably noticed that usually you’ll have file name in the format of “database name + backup + date + time + .bak”. For example, a backup from the master database may look like this: “master_backup_2012_10_02_220558_8601773.bak”.  It can be a challenge to script out automatic restores because the numbers on the end of the backup name constantly change. In this tip I will explain how to script out RESTORE DATABASE statements using DateTime functions.

Let’s say we have a folder full of backups like this:

Let’s say our boss wants us to restore Monday’s production backup (Alabama) every Friday afternoon to our development database (Tide). To accomplish this task, we can use the built-in SQL Server DateTime functions.

The below script will restore from the backup created on the first day of the current week.  I’ve added comments to explain the code.

— Declare variables
DECLARE @backup nvarchar(200)
DECLARE @datebegin datetime
DECLARE @dateend datetime

— Initalize variables
— Set @datebegin equal to the first day of the current week
SELECT @datebegin = DATEADD(wk,DATEDIFF(wk,0,GETDATE()),0)
— Set @dateend equal to the second day of the current week
SELECT @dateend = DATEADD(wk,DATEDIFF(wk,0,GETDATE()),1)

— Set @backup equal to query dependent on datebegin and dateend
SELECT TOP 1 @backup = name + ‘.bak’
FROM msdb..backupset
WHERE database_name = ‘Alabama’
AND backup_start_date BETWEEN @datebegin AND @dateend
AND type = ‘D’ — D is for full backups
ORDER BY backup_start_date ASC

USE [master]

— Put DB in Single_User Mode
ALTER DATABASE [Tide] SET SINGLE_USER WITH ROLLBACK IMMEDIATE

— Restore DB using query from @backup variable
RESTORE DATABASE [Tide] FROM  DISK = @backup WITH FILE = 1, NOUNLOAD, REPLACE, STATS = 5
GO

Below is a table of useful DateTime functions that you can use for the @datebegin and @dateend variables.

Another example may include where you need to take a backup from the first of the month of the production database and restore it weekly to the development database. In this situation you can edit the @datebegin and @dateend variables:

–Set @datebegin equal to the first day of the current month
SELECT @datebegin = DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)
 
–Set @dateend equal to the second day of the current month
SELECT @dateend = SELECT DATEADD(mm,DATEDIFF(mm,0,GETDATE()),1)

A quick and easy way to see if your DateTime functions are correct is to use the following:

–Declare variables
DECLARE @backup nvarchar(200)
DECLARE @datebegin datetime
DECLARE @dateend datetime
 
–Set @datebegin equal to the first day of the current week
SELECT @datebegin = DATEADD(wk,DATEDIFF(wk,0,GETDATE()),0)
 
–Set @dateend equal to the second day of the current week
SELECT @dateend = DATEADD(wk,DATEDIFF(wk,0,GETDATE()),1)
SELECT TOP 1 @backup = name + ‘.bak’
FROM msdb..backupset
WHERE database_name = ‘Alabama’
AND backup_start_date BETWEEN @datebegin AND @dateend
ORDER BY backup_start_date ASC
 
PRINT @datebegin
PRINT @dateend
PRINT @backup
After running this query you should return the dates and the backup name that will be used in the RESTORE statement:

From looking at the results returned I can determine that the @datebegin variable equals Monday, Oct 1, the @dateend variable equals Tuesday, October 2, and the backup that will be used for the restore is the backup created on Monday, Oct 1 at 10:15 PM.

Thanks for reading this article,

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