SQL Server BACKUP DATABASE Statement

Regular backups are crucial for protecting your SQL Server databases from data loss due to hardware failure, accidental deletion, or other unforeseen events. SQL Server provides commands to create both full and differential backups.

Full Database Backups (BACKUP DATABASE)

A full database backup creates a complete copy of your database at a specific point in time. While straightforward, full backups take longer than differential backups, especially for large databases, because the entire database must be copied.

Syntax

BACKUP DATABASE databasename
TO DISK = 'filepath';
      

Replace databasename with the name of your database and filepath with the desired location for the backup file. It's best practice to back up to a different physical drive than the one containing your database to protect against drive failure.

Example: Creating a Full Backup

This example creates a full backup of the database "testDB" to the file 'D:\backups\testDB.bak'.

BACKUP DATABASE testDB TO DISK = 'D:\backups\testDB.bak';
      

Differential Database Backups

A differential backup is a more efficient method for backing up databases that only change incrementally over time. It only backs up the portions of the database that have been modified since the last full database backup. This significantly reduces backup time and storage space compared to creating full backups frequently.

Creating a Differential Backup

To create a differential backup, use the WITH DIFFERENTIAL clause.

BACKUP DATABASE databasename
TO DISK = 'filepath'
WITH DIFFERENTIAL;
      

Example: Creating a Differential Backup

BACKUP DATABASE testDB TO DISK = 'D:\backups\testDB_diff.bak' WITH DIFFERENTIAL;