entdemo

init mod

go mod init github.com/xlzhangkeke/entdemo

create schema

go run -mod=mod entgo.io/ent/cmd/ent init User
go run -mod=mod entgo.io/ent/cmd/ent init Car Group

配置schema的fields和edges

generate schema ent code

go generate ./ent

生成schema entity

通过执行migration

[pause] https://entgo.io/docs/schema-fields

Relation definitions between A and B, where A is the owner of the edge and B uses this edge as a back-reference:

• O2O

  1. A have a unique edge (E) to B, and B have a back-reference unique edge (E') for E.
  2. A have a unique edge (E) to A.

• O2M (The "Many" side, keeps a reference to the "One" side).

  1. A have an edge (E) to B (not unique), and B doesn't have a back-reference edge for E.
  2. A have an edge (E) to B (not unique), and B have a back-reference unique edge (E') for E.

• M2O (The "Many" side, holds the reference to the "One" side).

  1. A have a unique edge (E) to B, and B doesn't have a back-reference edge for E.
  2. A have a unique edge (E) to B, and B have a back-reference non-unique edge (E') for E.

• M2M

  1. A have an edge (E) to B (not unique), and B have a back-reference non-unique edge (E') for E.
  2. A have an edge (E) to A (not unique).