英文:
$push string as an array in mongo document
问题
我在Go语言中遇到了一些理解数组的问题，特别是在使用GraphQL和MongoDB时。在JavaScript中，这对我来说都很容易，但我想知道你是否可以看看我的代码并指出明显的错误！
我希望对象的结构如下所示：
time
├── login
│ ├── 0
│ │ └── "2021-08-16T20:11:54-07:00"
│ ├── 1
│ │ └── "2021-08-16T20:11:54-07:00"
│ └── 2
└── "2021-08-16T20:11:54-07:00"
models.go:
type Time struct {
Login []string
}
type User struct {
ID graphql.ID
Time Time
}
schema.graphql:
type Time {
login: [String!]!
}
type User {
id: ID!
time: Time!
}
database.go:
filter := bson.D{{Key: "email", Value: email}}
arr := [1]string{time.Now().Format(time.RFC3339)}
update := bson.D{
{Key: "$push", Value: bson.D{
{Key: "time.login", Value: arr},
}},
}
result, err := collection.UpdateOne(ctx, filter, update)
我还尝试过：
update := bson.D{
{Key: "$push", Value: bson.D{
{Key: "time.login", Value: time.Now().Format(time.RFC3339)},
}},
}
result, err := collection.UpdateOne(ctx, filter, update)
但总是遇到相同的错误：
英文:
I'm having trouble understanding arrays in Go, especially with both graphql and mongo. With JS this all would've been a breeze for me, but I'm wondering if you can look at what I have and point out the obvious!
I'm looking for an object to be shaped like the following:
time
├── login
│ ├── 0
│ │ └── "2021-08-16T20:11:54-07:00"
│ ├── 1
│ │ └── "2021-08-16T20:11:54-07:00"
│ └── 2
└── "2021-08-16T20:11:54-07:00"
models.go:
type Time struct {
Login []string
}
type User struct {
ID graphql.ID
Time Time
}
schema.graphql:
type Time {
login: [String!]!
}
type User {
id: ID!
time: Time!
}
database.go:
filter := bson.D{{Key: "email", Value: email}}
arr := [1]string{time.Now().Format(time.RFC3339)}
update := bson.D{
{Key: "$push", Value: bson.D{
{Key: "time.login", Value: arr},
}},
}
result, err := collection.UpdateOne(ctx, filter, update)
I've also tried:
update := bson.D{
{Key: "$push", Value: bson.D{
{Key: "time.login", Value: time.Now().Format(time.RFC3339)},
}},
}
result, err := collection.UpdateOne(ctx, filter, update)
But always end up with the same error:
error="write exception: write errors: [The field 'time.login' must be an array but is of type null in document {_id: ObjectId('611b28fabffe7f3694bc86dc')}]"
答案1
得分: 0
[1]string{} 是一个数组。[]string{} 是一个切片。这两者是不同的。数组是一个固定大小的对象。切片可以动态地增长/缩小。
在这种情况下，你不应该使用任何一个，因为$push需要一个值，而不是一个切片：
update := bson.D{
{Key: "$push", Value: bson.D{
{Key: "time.login", Value: time.Now().Format(time.RFC3339)},
}},
}
英文:
[1]string{} is an array. []string{} is a slice. The two are different. An array is a fixed size object. A slice can grow/shrink dynamically.
In this case, you should not be using either, because $push gets a value, not a slice:
update := bson.D{
{Key: "$push", Value: bson.D{
{Key: "time.login", Value: time.Now().Format(time.RFC3339)},
}},
}
答案2
得分: 0
尝试初始化切片。
并使用append。
英文:
Try initializing the slice.
And use append.
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论