![]() ![]() If you want to restore the database to a specific point in time, you need restore a full, recent differential, and all the corresponding transaction log records which are necessary to build the database up to that specific point, or to a point very close to the desired point in time, just before the occurrence of the accident that resulted in the data loss. This means that the transaction log backups are incremental and differential backups are cumulative in nature. ![]() It allows the database to be recovered to a specific point in time. A transaction log backup contains all log records that have not been included in the last transaction log backup. A transaction log file stores a series of the logs that provide the history of every modification of data, in a database. This backup type is possible only with full or bulk-logged recovery models. The log backup, as its name implies, backs up the transaction logs. The BACKUP DATABASE command is used with the differential clause to create the differential database backup. How to create Differential database backup using T-SQL Typically, we would restore the most recent full backup followed by the most recent differential backup that is based on that full backup. A large differential backup loses the advantages of a faster and smaller backup as it requires the full backup to be restored before restoring the recent differential backup. ![]() The longer the age of a differential backup and larger the size and at some point in time it may reach the size of the full backup. However, as data changes over time, the differential backup size also increases. Therefore, it is recommended to take a new full backup, at set intervals, to establish a new differential base for the data.ĭifferential backups save storage space and the time it takes for a backup. As the differential backups increase in size, restoring a differential backup can significantly increase the time that is required to restore a database. If you create a series of differential backups, a frequently-updated database is likely to contain different data in each differential. A differential database backup captures the state of the changed extents at the time that backup was created. It requires at least two input parameters: the database name and the backup device.įollowing is the example for a full database backup to be stored in a device:Ī differential database backup is the superset of the last full backup and contains all changes that have been made since the last full backup. So, if there are very few transactions that have happened recently, a differential backup might be small in size, but if you have made a large number of transactions, the differential backup could be very large in size.Īs a differential backup doesn’t back up everything, the backup usually runs quicker than a full backup. The BACKUP DATABASE is the command used to create a full database backup. How to create full database backup using T-SQL This allows for the simplest form of database restoration, since all of the contents are contained in one single backup.Ī full backup must be done at least once before any of the other types of backups can be run-this is the foundation for every other kind of backup. Having a full backup, you will be able to easily restore a database in exactly the same form as it was at the time of the backup.Ī full backup creates a complete backup of the database as well as part of the transaction log, so the database can be recovered. ![]() This is a complete copy, which stores all the objects of the database: Tables, procedures, functions, views, indexes etc. It is the foundation of any kind of backup. There are other backup types available as well:Ī full backup, as the name implies, backs up everything. This understanding would, in turn, help us decide our backup-and-restore strategy.įollowing are the most common types of backups available in SQL Server: In this article, however, we are going to focus on the types of backups that are available to us, and understand how to pick what we need, and what aspects we base that decision on. SQL Server backups, in itself, is a vast subject so vast, there are multiple books written about them. ![]()
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