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Databases Modifying Data with SQL Updating Data in a Database Update All Rows or Columns in a Table

Posted by John Fowler
John Fowler
7,913 Points

Updating

When you update a value with SET are you changing that value permanently? If so, how could you recover the original value?

3 Answers

Adlay Almeida
Adlay Almeida
3,310 Points

Yes John, unless the statement is placed in a transaction block (which would then require the committing of that transaction for it to be final), executing the UPDATE statement will permanently change the record or records. There is no simple way to recover the contents, hence the propensity in the DB community to create backups of both tables and databases.

Thomas Nilsen
Thomas Nilsen
14,957 Points
Thomas Nilsen
Thomas Nilsen
14,957 Points

The closest you'll get is using something like this

Jon Phillips
Jon Phillips
1,217 Points
Jon Phillips
Jon Phillips
1,217 Points

Would the command work if done on a primary key? And if so, would that make the table unuseable?

Adlay Almeida
Adlay Almeida
3,310 Points

Yes Jon, I believe a primary key can be updated just like any other column. If it is an identity column the engine will complain and ask you to turn a specific flag off before doing so.

However, from a structural standpoint this is highly recommended against. You should never update primary key values and I cannot think of a situation where a workaround is not available.