The ON DUPLICATE KEY UPDATE clause is used andīe performed instead, the statement requires theīe updated. See Section 13.2.7.3, “INSERT DELAYED Statement”, UPDATE to refer to the row to be inserted. In MySQL 8.0.19 and later, a row alias with one or more optionalĬolumn aliases can be used with ON DUPLICATE KEY Updated if a row to be inserted would cause a duplicate value in a In MySQL 8.0.19 and later to insert rows from a single table.ĭUPLICATE KEY UPDATE clause enables existing rows to be SELECT form inserts rows selected from another table | col_alias assignment_list:įorms of the statement insert rows based on explicitly specified ON DUPLICATE KEY UPDATE Statement 13.2.7.3 INSERT DELAYED Statement INSERT INSERT INTO view_check3 VALUES (150) ĮRROR 1369 (HY000): CHECK OPTION failed 'test.13.2.7.1 INSERT. The WHERE clause for view_check1 evaluates as false ( 150 is >10, but 150 is not <100), so the insert fails. This insert fails, as view_check3 checks the insert against both view_check3 and the underlying views. This insert succeeds, as view_check2 only checks the insert against view_check2, and the WHERE clause evaluates to true ( 150 is >10). CREATE VIEW view_check1 AS SELECT * FROM table1 WHERE x 10 WITH LOCAL CHECK OPTION ĬREATE VIEW view_check3 AS SELECT * FROM view_check1 WHERE x > 10 WITH CASCADED CHECK OPTION Here are three views to demonstrate the WITH CHECK OPTION clause.
UPDATE view1 SET y = 5 ĮRROR 1348 (HY000): Column 'y' is not updatable This query fails, since column y is a literal. This query works, as the view is updateable: UPDATE view1 SET x = 5 Examples CREATE TABLE table1 (x INT) ĬREATE VIEW view1 AS SELECT x, 99 AS y FROM table1 Ĭhecking whether the view is updateable: SELECT TABLE_NAME,IS_UPDATABLE FROM INFORMATION_SCHEMA.VIEWS An insertable view with a WHERE which is always false but no CHECK OPTION is a view that accepts data but does not show them. If a row is rejected because of the CHECK OPTION, an error similar to the following is produced: ERROR 1369 (HY000): CHECK OPTION failed 'db_name.view_name'Ī view with a WHERE which is always false (like WHERE 0) and WITH CHECK OPTION is similar to a BLACKHOLE table: no row is ever inserted and no row is ever returned. CASCADED is treated as default if neither keyword is given. WITH LOCAL CHECK OPTION restricts the CHECK OPTION to only the view being defined, while WITH CASCADED CHECK OPTION checks all underlying views as well. There are two keywords that can be applied. The WITH CHECK OPTION clause is used to prevent updates or inserts to views unless the WHERE clause in the SELECT statement is true. MariaDB stores an IS_UPDATABLE flag with each view, so it is always possible to see if MariaDB considers a view updatable (although not necessarily insertable) by querying the IS_UPDATABLE column in the INFORMATION_SCHEMA.VIEWS table. The following are examples of derived columns the view columns are all simple columns, and not derived in any way.no base table columns are present in view select list more than once.the view contains all base table columns that don't have default values.if there's a LIMIT clause, the view does not contain all primary or not null unique key columns from the underlying table and the updatable_views_with_limit system variable is set to 0.Ī view cannot be used for inserting if it fails any of the criteria for updating, and must also meet the following conditions:.an inner join where more than one table in the view definition is being updated.multiple references to any base table column.the FROM clause contains a non-updatdable view.if it has no underlying table because it refers only to literal values.subquery in the WHERE clause referring to a table in the FROM clause.An aggregate function, such as MAX(), MIN(), SUM() or COUNT().ALGORITHM=TEMPTABLE (see View Algorithms).
Updating with viewsĪ view cannot be used for updating if it uses any of the following:
A view can be used for inserting or updating.
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