Permissions on Arrays

When granting permissions on a field, if the field contains array data, you must grant the permission on the array field. This grants access to only array data in the field. It is also possible to set permissions on subfields within nested documents that are stored in an array.

Granting Permissions on Array Elements

Suppose you have the following documents where person is:

  • An array of nested documents in document id001
  • A single nested document in document id002
  • A scalar value in document id003
    "_id" : "id001",
    "person" : [
        {"name" : {"last" : "Smith", "first" : "John"}},
        {"name" : {"last" : "Subramanium", "first" : "Ananya"}}
    "_id" : "id002",
    "person" : {"name" : {"last" : "Doe", "first" : "Jane"}}
    "_id" : "id003",
    "person" : "Unknown"

If you grant a user read permission on the array person[], that user can read every field in every nested document within the array in document id001. The permission does not allow the user to read the person field in documents id002 and id003. You must define a separate permission on person.

You cannot grant permissions on individual elements in an array; for example: person[1]. Granting permission on an array enables access to the entire array.

Granting Permissions on Nested Document Fields in an Array

If you want to restrict read access to only specific fields in the array person[] , perform the following steps:

  1. Deny the user read permission on the array person[].
  2. Grant the user traverse permission on the array person[].
  3. Grant the user read permission on the specific fields.

For example, to grant the user read permission on only the first names in the nested documents, for the third step, grant read permission on person[].name.first. The permission enables the user to read the fields in only document id001. You must grant separate permissions on to enable reads on the field in document id002.