What are views in Oracle SQL?
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What are views in Oracle SQL?
In SQL, a view is a virtual table based on the result-set of an SQL statement. A view contains rows and columns, just like a real table. The fields in a view are fields from one or more real tables in the database.
How do you query a view in SQL?
To create a view, a user must have the appropriate system privilege according to the specific implementation. CREATE VIEW view_name AS SELECT column1, column2….. FROM table_name WHERE [condition]; You can include multiple tables in your SELECT statement in a similar way as you use them in a normal SQL SELECT query.
What is difference between table and view?
A view is a virtual table. A view consists of rows and columns just like a table. The difference between a view and a table is that views are definitions built on top of other tables (or views), and do not hold data themselves. If data is changing in the underlying table, the same change is reflected in the view.
What are the types of views in SQL?
There are three types of System defined views, Information Schema, Catalog View, and Dynamic Management View.
What are Oracle performance views?
Oracle contains a set of underlying views that are maintained by the database server and accessible to the database administrator user SYS . These views are called dynamic performance views because they are continuously updated while a database is open and in use, and their contents relate primarily to performance.
What is the difference between V $< tables and DBA _< tables?
V$TABLESPACE is a view on X$KCCTS , which is an internal memory structure. DBA_TABLESPACES is a view on the data dictionary table SYS.
What is user defined view in SQL?
A view is a virtual table whose contents are defined by a query. Like a table, a view consists of a set of named columns and rows of data. Unless indexed, a view does not exist as a stored set of data values in a database.
What are different views in SQL?
