Managing Backup and Restore of Databases in SQL Server 2016 Online Training

Backup and restoration of a database refers to making copies of all the data in a database (and its schema) so that it's protected against data loss or corruption. A database backup captures what's called the state of the database, including the data, configurations, and logs. Restoration is the process of using a backup to recover lost or damaged data, returning the database to a consistent and usable state.

The backup strategy that ensures the most comprehensive data protection with SQL Server 2016 involves full, differential, and transaction log backups done on a regular basis. A full backup is one that captures the entire database. A differential backup captures changes since the last full backup. Transaction log backups record transactional changes. Another essential part of the strategy is backup storage: offsite, regularly tested and complete with retention and restoration policies.

Backup and restoration is a crucial part of database management for two key reasons: data integrity and business continuity. Backup and restoration procedures, policies or strategies are different ways of making sure that an organization never loses access to its data and is always confident of its accuracy, even despite hardware failures (which happen all the time), software errors (which can always occur), or malicious activities (which are practically inevitable).

Many different things can go wrong and result in data loss or downtime when backing up and restoring databases, from errors to mistakes and failures. Some errors include possibilities like incomplete or corrupted backups, insufficient storage capacity, and compatibility issues between backup and restore environments. Humans can always make mistakes, as seen in misconfigurations or accidental deletion of backup files. And hardware, network and software failures are always a possibility.

As a general rule, SQL Server tries to support restoring databases across different versions, but as with any technology, there are limitations. Most versions of SQL Server are able to restore databases saved in older versions and maintain most of the functionality that was present in the previous version. However, restoring a database from a newer version to an older version is rarely possible due to potential compatibility issues and schema changes.