Summary: in this tutorial, you are going to learn about MySQL View. We will explain how MySQL implements views.
MySQL supports database views or views since version 5.X. In MySQL, almost features of views conform to the SQL: 2003 standard. MySQL process queries to the views in two ways:
- MySQL creates a temporary table based on the view definition statement and then executes the incoming query on this temporary table.
- First, MySQL combines the incoming query with the query defined the view into one query. Then, MySQL executes the combined query.
MySQL supports version system for views. Each time when the view is altered or replaced, a copy of the existing view is back up in arc (archive) folder which resides in a specific database folder. The name of back up file is view_name.frm-00001. If you then change the view again, MySQL will create a new backup file named view_name.frm-00002.
MySQL also allows you to create a view of views. In the SELECT statement of view definition, you can refer to another views.
If the cache is enabled, the query against a view is stored in the cache. As the result, it increases the performance of the query by pulling data from the cache instead of querying data from the underlyingtables.
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