1. Database Snapshot By: Mahta Woldeselassie Julian Bester

2. What is a Database Snapshot?  Database Snapshot is a static, read-only copy of an existing Microsoft SQL Server database.  When a snapshot is created, it is an exact read-only replica of the source database at that point in time.  As the source database changes, the snapshot will be updated to ensure that it is synchronized.

3. Benefits of Database Snapshots  Snapshots can be used for reporting purposes.  Clients can query a database snapshot, which makes it useful for writing reports based on the data at the time of snapshot creation.  Maintaining historical data for report generation.  You can create a database snapshot at the end of a given time period (such as a financial quarter) for later reporting. You can then run end-of-period reports on the snapshot.  Reverting to a database snapshot  One of the biggest advantages you can leverage by creating database snapshots is that you may be able to use them as a backup to a database backup.  For example, if someone accidently deleted data from a table in your database or a table has been dropped, instead of using a database backup you could use the snapshot. The snapshot may offer a more recent version of the database schema and data than your last backup.

4. Prerequisites and limitations of Database Snapshots  Database snapshots are supported only in the Enterprise version of SQL Server 2012  The source and the snapshot database must reside on the same SQL Server instance.  The source database or the snapshot can not be dropped, detached, or restored.  Performance could be negatively affected due to increased I/O on the source.  If a snapshot runs out of space, it must be deleted and re-created.

5. Creating a Database Snapshot

6. Database Snapshot in the Object Explorer

7. Dropping database snapshots  If you decide that a database snapshot is no longer useful or you want to start with a fresh snapshot, you can drop it.  There are two ‘very’ simple ways to drop a snapshot.

8. Dropping database snapshots (1)  Using the Object Explorer:

9. Dropping database snapshots (2)  In the query editor window:

10. Summary  Database snapshots offer you several ways to leverage a copy of the data and schema that may have not been available before. They are commonly used for reports and ad-hoc queries. In addition you can use them for backup in case of data loss. You must take into account additional space requirements and potential performance degradation when using this feature.