I'm currently working on a project where I need a tree in my database. To me, closure-table is the best bet because I will, at some point need multiple roots in the graph.

I am using typeorm 0.2.45 since nestJs doesn't support 0.3.* yet.

When adding entities to the database, without linkage, no problem:

// ./entity/Node.ts
import { Entity, PrimaryGeneratedColumn, Column, BaseEntity, Tree, PrimaryColumn, TreeParent, TreeChildren } from "typeorm"

@Entity()
@Tree("closure-table")
export class Node extends BaseEntity {

    @PrimaryColumn()
    name: string

    @TreeParent()
    parent: Node

    @TreeChildren()
    children: Node[]

}

import { AppDataSource } from "./data-source"
import { Node } from "./entity/Node"

AppDataSource.connect().then(async (conn) => {
    const rNode = conn.getTreeRepository(Node)

    await rNode.createQueryBuilder().delete().execute()

    const [root, child] = await Promise.all(['root', 'child'].map(async (name) => {
        await rNode.insert({name})
        return rNode.findOne(name)
    }))

    console.log(await rNode.findTrees())
}).catch(error => console.log(error))

yields

[
  Node { name: 'root', children: [] },
  Node { name: 'child', children: [] }
]

But as soon as I try to add relations within the tree, all goes bad..

import { AppDataSource } from "./data-source"
import { Node } from "./entity/Node"

AppDataSource.connect().then(async (conn) => {
    const rNode = conn.getTreeRepository(Node)

    await rNode.createQueryBuilder().delete().execute()

    const [root, child] = await Promise.all(['root', 'child'].map(async (name) => {
        await rNode.insert({name})
        return rNode.findOne(name)
    }))

    child.parent = root;
    await rNode.save(child);

    console.log(await rNode.findTrees())
}).catch(error => console.log(error))

Yields

[ Node { name: 'root', children: [] } ]

And the table node_closure is completely empty (note that when filling it properly I do have the tree appearing).

What have I done wrong ?

Thanks