Gbase8s how to delete data in a table with a foreign key relationship

GBase8s How to delete data in a table with a foreign key relationship

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Other answers 1：

There are two ways ：

1、 First delete the data in the foreign key table , Then delete the current data

give an example ：

drop table if exists t1;

drop table if exists t2;

create table t1(id int primary key , s1 float);

create table t2(id int , id1 int ,s1 float,foreign key(id1) references t1(id) );

insert into t1 values(1,20);

insert into t1 values(2,30);

insert into t2 values(1,1,50);

-- If you delete t1 The data of , False report

delete t1;

692: Key value for constraint (root.u143_565) is still being referenced.

Error in line 1

Near character position 8

 

-- You need to delete t2 Table data , To delete t1 Table data

delete t2;

delete t1;

 

2、 Cascading deletion can be set through foreign keys

-- When setting foreign keys , Set cascade delete

drop table t2;

drop table t1;

create table t1(id int primary key , s1 float);

create table t2(id int , id1 int ,s1 float,foreign key(id1) references t1(id) on delete cascade);

insert into t1 values(1,20);

insert into t1 values(2,30);

insert into t2 values(1,1,50);

-- Delete... At this time t1 The data of , Delete t1 And t2 Data in the

> delete t1;

2 row(s) deleted.

> select * from t2;

         id        id1            s1 

No rows found.