Creating views
In this recipe, you will learn how to create a view
in Hive.
Getting ready
A view
is a virtual table that acts as a window to the data for the underlying table commonly known as the base
table. It consists of rows and columns but no physical data. So when a view
is accessed, the underlying base
table is queried for the output.
Note
A base
table can also be a view
that will have a base
table of its own. So if the first view
is accessed, then the base
table of the second view
gives the output for the query.
The general syntax of creating a view
is as follows:
CREATE VIEW [IF NOT EXISTS] view_name [(column_name [COMMENT column_comment], ...)] [COMMENT view_comment] [TBLPROPERTIES (property_name = property_value, ...)] AS SELECT ...;
Where:
[IF NOT EXISTS]
: Is an optional clause. If there is an attempt to create aview
that is already present in the database, then an error is thrown. In such cases, theIF NOT EXISTS
clause is used, which will ignore the entire statement and...