1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
// Copyright 2019-present Facebook Inc. All rights reserved.
// This source code is licensed under the Apache 2.0 license found
// in the LICENSE file in the root directory of this source tree.
package main
import (
"context"
"fmt"
"log"
"github.com/facebook/ent/examples/m2mrecur/ent/user"
"github.com/facebook/ent/examples/m2mrecur/ent"
_ "github.com/mattn/go-sqlite3"
)
func Example_M2MRecur() {
client, err := ent.Open("sqlite3", "file:ent?mode=memory&cache=shared&_fk=1")
if err != nil {
log.Fatalf("failed opening connection to sqlite: %v", err)
}
defer client.Close()
ctx := context.Background()
// Run the auto migration tool.
if err := client.Schema.Create(ctx); err != nil {
log.Fatalf("failed creating schema resources: %v", err)
}
if err := Do(ctx, client); err != nil {
log.Fatal(err)
}
// Output:
// [User(id=2, age=28, name=nati)]
// []
// []
// [User(id=1, age=30, name=a8m)]
// [28]
// [a8m]
}
func Do(ctx context.Context, client *ent.Client) error {
// Unlike `Save`, `SaveX` panics if an error occurs.
a8m := client.User.
Create().
SetAge(30).
SetName("a8m").
SaveX(ctx)
nati := client.User.
Create().
SetAge(28).
SetName("nati").
AddFollowers(a8m).
SaveX(ctx)
// Query following/followers:
flw := a8m.QueryFollowing().AllX(ctx)
fmt.Println(flw)
// Output: [User(id=2, age=28, name=nati)]
flr := a8m.QueryFollowers().AllX(ctx)
fmt.Println(flr)
// Output: []
flw = nati.QueryFollowing().AllX(ctx)
fmt.Println(flw)
// Output: []
flr = nati.QueryFollowers().AllX(ctx)
fmt.Println(flr)
// Output: [User(id=1, age=30, name=a8m)]
// Traverse the graph:
ages := nati.
QueryFollowers(). // [a8m]
QueryFollowing(). // [nati]
GroupBy(user.FieldAge). // [28]
IntsX(ctx)
fmt.Println(ages)
// Output: [28]
names := client.User.
Query().
Where(user.Not(user.HasFollowers())).
GroupBy(user.FieldName).
StringsX(ctx)
fmt.Println(names)
// Output: [a8m]
return nil
}
|
