ALTER VIEW statement
ALTER VIEW statement changes the characteristics of a
Because a view is a logical construct, an alias for a query, with no physical data behind
ALTER VIEW only involves changes to metadata in the metastore
database, not any data files in HDFS.
To see the definition of the updated view, issue a
ALTER VIEW [database_name.]view_name [(column_name [COMMENT 'column_comment'][, ...])] AS select_statement; ALTER VIEW [database_name.]view_name RENAME TO [database_name.]view_name; ALTER VIEW [database_name.]view_name SET OWNER USER user_name; ALTER VIEW [database_name.]view_name SET OWNER ROLE role_name; ALTER VIEW [database_name.]view_name SET TBLPROPERTIES ('name' = 'value'[, 'name' = 'value' ...]); ALTER VIEW [database_name.]view_name UNSET TBLPROPERTIES ('name'[, ...]);
ASclause associates the view with a different query.
An optional list of column names can be specified with or without the column-level comments.For example:
ALTER VIEW v1 AS SELECT x, UPPER(s) s FROM t2; ALTER VIEW v1 (c1, c2) AS SELECT x, UPPER(s) s FROM t2; ALTER VIEW v7 (c1 COMMENT 'Comment for c1', c2) AS SELECT t1.c1, t1.c2 FROM t1;
RENAME TOclause changes the name of the view, moves the view to a different database, or both.For example:
ALTER VIEW db1.v1 RENAME TO db2.v2; -- Move the view to a different database with a new name. ALTER VIEW db1.v1 RENAME TO db1.v2; -- Rename the view in the same database. ALTER VIEW db1.v1 RENAME TO db2.v1; -- Move the view to a difference database with the same view name.
SET OWNERclause transfers the ownership of the view from the current owner to another user or a role.
The view owner is originally set to the user who creates the view. When object ownership is enabled in Ranger, an owner of a view can have the
GRANTprivilege. The term
OWNERis used to differentiate between the
ALLprivilege that is explicitly granted via the
GRANTstatement and a privilege that is implicitly granted by the
SET TBLPROPERTIESclause is primarily a way to associate arbitrary user-specified data items with a particular view.
You can associate arbitrary items of metadata with a table by specifying the
TBLPROPERTIESclause. This clause takes a comma-separated list of key-value pairs and stores those items in the metastore database. You can also unset the view properties later with an
UNSET TBLPROPERTIESclause.For example:
ALTER VIEW v1 SET TBLPROPERTIES ('tblp1' = '1', 'tblp2' = '2'); ALTER VIEW v1 UNSET TBLPROPERTIES ('tblp1', 'tblp2');
Statement type: DDL
If you connect to different Impala nodes within an
impala-shell session for load-balancing purposes, you can enable the
SYNC_DDL query option to make each DDL statement wait before returning,
until the new or changed metadata has been received by all the Impala nodes.
If these statements in your environment contain sensitive literal values such as credit card numbers or tax identifiers, Impala can redact this sensitive information when displaying the statements in log files and other administrative contexts.
Cancellation: Cannot be cancelled.
HDFS permissions: This statement does not touch any HDFS files or directories, therefore no HDFS permissions are required.