Help Center/ GaussDB/ Feature Guide(Centralized_8.x)/ Materialized View/ Fast-Refresh Materialized View/ Usage
Updated on 2024-06-07 GMT+08:00
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Usage

Syntax

  • Create a fast-refresh materialized view. 
    CREATE INCREMENTAL MATERIALIZED VIEW view_name AS query;
  • Completely refresh a materialized view. 
    REFRESH MATERIALIZED VIEW view_name;
  • Fast refresh a materialized view. 
    REFRESH INCREMENTAL MATERIALIZED VIEW view_name;
  • Drop a materialized view. 
    DROP MATERIALIZED VIEW view_name;
  • Query a materialized view. 
    SELECT * FROM view_name;

Parameters

  • view_name

    Specifies the name of the materialized view to be created.

    Value range: a string. It must comply with the identifier naming convention.

  • AS query

    Specifies a SELECT or VALUES command, or an EXECUTE command that runs a prepared SELECT or VALUES query.

Examples

-- Change the default type of a table.
gaussdb=#  set enable_default_ustore_table=off;

-- Prepare data.
gaussdb=# CREATE TABLE t1(c1 int, c2 int);
gaussdb=# INSERT INTO t1 VALUES(1, 1);
gaussdb=# INSERT INTO t1 VALUES(2, 2);

-- Create a fast-refresh materialized view.
gaussdb=# CREATE INCREMENTAL MATERIALIZED VIEW mv AS SELECT * FROM t1;
CREATE MATERIALIZED VIEW

-- Insert data.
gaussdb=# INSERT INTO t1 VALUES(3, 3);
INSERT 0 1

-- Fast refresh the materialized view.
gaussdb=# REFRESH INCREMENTAL MATERIALIZED VIEW mv;
REFRESH MATERIALIZED VIEW

-- Query the materialized view result.
gaussdb=# SELECT * FROM mv;
 c1 | c2 
----+----
  1 |  1
  2 |  2
  3 |  3
(3 rows)

-- Insert data.
gaussdb=# INSERT INTO t1 VALUES(4, 4);
INSERT 0 1

-- Completely refresh the materialized view.
gaussdb=# REFRESH MATERIALIZED VIEW mv;
REFRESH MATERIALIZED VIEW

-- Query the materialized view result.
gaussdb=# select * from mv;
 c1 | c2 
----+----
  1 |  1
  2 |  2
  3 |  3
  4 |  4
(4 rows)

-- Drop the materialized view and table.
gaussdb=# DROP MATERIALIZED VIEW mv;
DROP MATERIALIZED VIEW
gaussdb=# DROP TABLE t1; 
DROP TABLE