How to do cascading inserts with tables having auto increment id columns in TypeORM - mysql

Question

I am trying to implement cascading inserts using typeorm. The child table entries include a foreign key reference to the ID field on the parent table.
It seems typeorm is not capturing the auto-increment id from the parent row and supplying it to the child inserts.
Here is the parent Entity:
import ...
#Entity("parent")
export class Parent {
#PrimaryGeneratedColumn()
id: number;
#OneToOne(type => Account, accountId => accountId.provider)
#JoinColumn({name: "account_id"})
accountId: Account;
#Column("varchar", {
name: "name",
nullable: false,
length: 255,
})
name: string;
#OneToMany(type => Child, Children => Children.parentId, {
cascadeInsert: true,
cascadeUpdate: true
})
Children: Child[];
}
and the child entity:
import ...
#Entity("child")
export class Child{
#PrimaryGeneratedColumn()
id: number;
#ManyToOne(type => Parent, parentId => parentId.children)
#JoinColumn({name: "parent_id"})
parentId: Parent;
#Column("varchar", {
name: "number",
nullable: true,
length: 45,
})
number: string;
}
the console log shows that the sql being generated does not include the foreign key column, producing the obvious error ER_NO_DEFAULT_FOR_FIELD: Field 'parent_id' doesn't have a default value
info: executing query: START TRANSACTION
info: executing query: INSERT INTO parent(name, account_id) VALUES (?,?) -- PARAMETERS: ["Name","id"]
info: executing query: INSERT INTO child(number) VALUES (?) -- PARAMETERS: ["12345678"]
info: query failed: INSERT INTO child(number) VALUES (?) -- PARAMETERS: ["12345678"]
info: error: { Error: ER_NO_DEFAULT_FOR_FIELD: Field 'parent_id' doesn't have a default value
Is there some way that typeorm can be instructed to capture the LAST_INSERT_ID() or otherwise populate the foregin key id field on the child row?

Answer 1

If the id is not auto generated, but assigned before saving the entity, it works.
Use a uuid as primary key.
import ...
#Entity("parent")
export class Parent {
#PrimaryColumn()
id: string;
#OneToOne(type => Account, accountId => accountId.provider)
#JoinColumn({name: "account_id"})
accountId: Account;
#Column("varchar", {
name: "name",
nullable: false,
length: 255,
})
name: string;
#OneToMany(type => Child, Children => Children.parentId, {
cascadeInsert: true,
cascadeUpdate: true
})
Children: Child[];
}
and when you create the entity.
const parent: Parent = new Parent();
parent.id = "896b677f-fb14-11e0-b14d-d11ca798dbac"; // your uuid goes here
Unfortunately you can not use #PrimaryGeneratedColumn("uuid") either.
There are a lot of libraries to generate a uuid in JS.
Example with uuid-js - https://github.com/pnegri/uuid-js
const parent: Parent = new Parent();
parent.id = UUID.create(4).toString();
I think this is more like a workaround, rather than a solution to the problem. But I could not find a way to tell TypeORM to consider generated ids when cascading children.