typeorm dbfirst的模式

a对象有id,name;b对象有id,name;c对象id，a_id，b_id。其中a.id为主键。b.id为主键；c.id为主键，c.a_id为外键和a.id关联，a和c的关系为1:N，c.b_id为外键和b.id关联，b和c的关系为1：N，请使用typeorm生成a.c.b和的b.c.a关系

import {

    Entity,
    PrimaryGeneratedColumn,
    Column,
    OneToMany,
    ManyToOne,
    JoinColumn,
} from 'typeorm';

@Entity('a')
export class A {
    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    name: string;

    @OneToMany(() => C, (c) => c.a)
    c: C[];
}

@Entity('b')
export class B {
    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    name: string;

    @OneToMany(() => C, (c) => c.b)
    c: C[];
}

@Entity('c')
export class C {
    @PrimaryGeneratedColumn()
    id: number;

    @ManyToOne(() => A, (a) => a.c)
    @JoinColumn({ name: 'a_id' })
    a: A;

    @ManyToOne(() => B, (b) => b.c)
    @JoinColumn({ name: 'b_id' })
    b: B;

    @Column()
    a_id: number;

    @Column()
    b_id: number;
}