SQL::ReferentialUpdateRule Enumerated Type

Description

This is an enumerated type is used to describe desired behavior when an update or a delete occurs for a table that has references to it from one or more other tables. The value is specified as an update or delete rule for a specific reference (foreign key relationship) and is a constraint on the referencing table. The values in the following list are supported:

Value: Description
Restrict: 0
Cascade: 1
SetNull: 2
SetDefault: 3

Dim Index as SQL::IndexInfo
Index.ReferencedTable = MyReferencedTable
?
Index.DeleteRule = SetNull
Index.UpdateRule = Cascade

The resulting create table statements. Note the italicized ON clauses in the second table.

CREATE TABLE MyReferencedTable
(
    Key1 VARCHAR NOT NULL,
    ?
    PRIMARY KEY (Key1)
)
CREATE TABLE MyReferencingTable
(
    Key1 VARCHAR(5) NOT NULL,
    Key2 VARCHAR(5) NOT NULL,
    ?
    PRIMARY KEY (Key1, Key2),
    FOREIGN KEY (Key1) REFERENCES MyReferencedTable
    ON DELETE SET NULL
    ON UPDATE CASCADE
)

Limitations

Internal use only.