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jonesrob797 avatar image
jonesrob797 asked

differential backup

Hello, receive an error: "Cannot perform a differential backup for database ..., because a current database backup does not exist." Can't fully understand what to do with this
sql server
10 |1200

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davismick643 avatar image
davismick643 answered
Differential backups are a type of backup which stores the changes which have occurred in your database since the last FULL database backup. In order to be able to create a differential backup you will need to have a FULL database backup before. Multiple differential backups can be created later, which store the incremental changes in your database since your last FULL or DIFFERENTIAL backup, but having a FULL backup is mandatory as this is the base for your later backups which are of a different type(differential or transaction log). I can propose a few articles to you. 1. [ https://technet.microsoft.com/en-us/library/ms190412%28v=sql.105%29.aspx][1] 2. [ http://sqlbak.com/blog/cannot-perform-a-differential-backup/][2] Hope that will be useful [1]: https://technet.microsoft.com/en-us/library/ms190412%28v=sql.105%29.aspx [2]: http://sqlbak.com/blog/cannot-perform-a-differential-backup/
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Since you just copied/pasted from the sqlbak page, I assume you're associated with the product? Maybe you could fix an error in the article. The article is incorrect when it states that a differential backup can store incremental changes since your last DIFFERENTIAL backup. A differential backup only stores changes since your last FULL backup. It has no relationship to any other differential backup you may have taken. The article you probably should have linked to is the MSDN Differential Backups topic which clearly states "A differential backup is based on the most recent, previous full data backup. A differential backup captures only the data that has changed since that full backup. " - https://msdn.microsoft.com/en-us/library/ms175526(v=sql.120).aspx
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