Advantage of using Views in MySQL

Question

I\'ve learned that views can be used to create custom \"table views\" (so to say) that aggregate related data from multiple tables.

My question is: what are the adva

Answer 1

You can restrict users to the view instead of the underlying table(s), thereby enhancing security.

Answer 2

A view is not stored separately: when you query a view, the view is replaced with the definition of that view. So and changes to the data in the tables will show up immediately via the view.

In addition to the security feature pointed out earlier:

If you're writing a large number of queries that would perform that join, it factors out that SQL code. Like doing some operations in a function used in several places, it can make your code easier to read/write/debug.

It would also allow you to change how the join is performed in the future in one place. Perhaps a 1-to-many relationship could become a many-to-many relationship, introducing an extra table in the join. Or you may decide to denormalize and include all of the eventtype fields in each event record so that you don't have to join each time (trading space for query execution time).

You could further split tables later, changing it to a 3-way join, and other queries using the view wouldn't have to be rewritten.

You could add new columns to the table(s) and change the view to leave out the new columns so that some older queries using "select *" don't break when you change the table definitions.