How to present dynamic keys in a type struct? - sql

Question

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!

Answer 1

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.