How To Update Foreign Key Value In Oracle

Sql> alter table emp1 2 add constraint fk_deptno1 foreign key (deptno) 3 references dept1(deptno) initially deferred ; table altered. sql> update dept1 set deptno=deptno+1 ; sql> update emp1 set deptno=deptno+1 ; and it allows me to directly update without using set constraints clause.. Another way could be: 1. create one more record in table p with code=200 and rest all column having same values as record with code=100. 2. update column p_code in child tables such that p_code = 200 where p_code = 100.. This section describes how foreign keys help guarantee referential integrity. for storage engines supporting foreign keys, mysql rejects any insert or update operation that attempts to create a foreign key value in a child table if there is no a matching candidate key value in the parent table..

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If foreign keys should only reference a primary key, and any other use of it is bad design, the initial objection then does not hold weight. as oracle allows foreign keys to reference a unique constraint, then there's no theoretical reason to not have on update cascade as well.. ### oracle prides itself on introducing features in the database that allow one to build-in good design practices into an oracle database application. introduction of primary key and foreign key constraints did that initially. this just enhances the primary key to enforce its immutability. good data modelers everywhere would like this feature.. The column tblinvesttypecomp.type_code is a foreign key referencing tblinvesttype.type_code. how can i create a trigger such that whenever there is any update in the values of the parent table's (tblinvesttype) type_code column, the same is reflected to the child table's (tblinvesttypecomp) type_code column? note: all this is in oracle..

how to update foreign key value in oracle

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