英文:
How to present dynamic keys in a type struct?
问题
我有一个包含JSONB字段的PostgreSQL表。可以通过以下方式创建该表：
create table mytable
(
id uuid primary key default gen_random_uuid(),
data jsonb not null
);
在上面的示例中，我使用"0x101"和"0x102"来表示两个UID。实际上，它可能有更多的UID。
我正在使用jackc/pgx来读取该JSONB字段。
以下是我的代码：
import (
"context"
"fmt"
"github.com/jackc/pgx/v4/pgxpool"
)
type Data struct {
UserRoles struct {
UID []string `json:"uid,omitempty"`
// 上面的代码不起作用，因为没有名为"uid"的固定字段。
// 相反，它们是"0x101"、"0x102"等等。
} `json:"user_roles,omitempty"`
}
type MyTable struct {
ID string
Data Data
}
pg, err := pgxpool.Connect(context.Background(), databaseURL)
sql := "SELECT data FROM mytable"
myTable := new(MyTable)
err = pg.QueryRow(context.Background(), sql).Scan(&myTable.Data)
fmt.Printf("%v", myTable.Data)
如上面的注释所提到的，上述代码不起作用。
如何在类型结构中表示动态键，或者如何返回所有JSONB字段的数据？谢谢！
英文:
I have a PostgreSQL table which has a JSONB filed. The table can be created by
create table mytable
(
id uuid primary key default gen_random_uuid(),
data jsonb not null,
);
insert into mytable (data)
values ('{
"user_roles": {
"0x101": [
"admin"
],
"0x102": [
"employee",
"customer"
]
}
}
'::json);
In above example, I am using "0x101", "0x102" to present two UIDs. In reality, it has more UIDs.
I am using jackc/pgx to read that JSONB field.
Here is my code
import (
"context"
"fmt"
"github.com/jackc/pgx/v4/pgxpool"
)
type Data struct {
UserRoles struct {
UID []string `json:"uid,omitempty"`
// ^ Above does not work because there is no fixed field called "uid".
// Instead they are "0x101", "0x102", ...
} `json:"user_roles,omitempty"`
}
type MyTable struct {
ID string
Data Data
}
pg, err := pgxpool.Connect(context.Background(), databaseURL)
sql := "SELECT data FROM mytable"
myTable := new(MyTable)
err = pg.QueryRow(context.Background(), sql).Scan(&myTable.Data)
fmt.Printf("%v", myTable.Data)
As the comment inside mentions, the above code does not work.
How to present dynamic keys in a type struct or how to return all JSONB field data? Thanks!
答案1
得分: 1
请将您的数据结构编辑如下：
type Data struct {
UserRoles map[string][]string `json:"user_roles,omitempty"`
}
如果您正在使用类似于https://github.com/google/uuid的包来处理UUID，您还可以将UUID类型用作映射的键类型。
但请注意，如果在JSON对象的user_roles字段中为特定用户（具有相同的UUID）有多个条目，只会获取其中一个条目。
英文:
edit your Data struct as follows,
type Data struct {
UserRoles map[string][]string `json:"user_roles,omitempty"`
}
you can also use a uuid type as the map's key type if you are using a package like https://github.com/google/uuid for uuids.
However please note that this way if you have more than one entry in the json object user_roles for a particular user(with the same uuid), only one will be fetched.
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