class_docstr: Calls to :meth:`orion.core.io.database.AbstractDB.read`.
docstr: Fetch value(s) from an entry.
docstr_tok: ["Fetch","value","(","s",")","from","an","entry","."]
code: def test_null_comp(self, orion_db):
      """Fetch value(s) from an entry."""
      all_values = orion_db.read(
          "test_collection",
          {
              "same_field": "same",
              "datetime": {"$gte": datetime(2017, 11, 1, 0, 0, 0)},
          },
      )
  
      db = get_db(orion_db)
      db["test_collection"]._documents[0]._data["datetime"] = None
      dump_db(orion_db, db)
  
      values = orion_db.read(
          "test_collection",
          {
              "same_field": "same",
              "datetime": {"$gte": datetime(2017, 11, 1, 0, 0, 0)},
          },
      )
      assert len(values) == len(all_values) - 1
  
imports: import pickle
  from datetime import datetime
  import pytest
  from orion.core.io.database import Database, DatabaseError, DuplicateKeyError
  from orion.core.io.database.ephemeraldb import EphemeralDB
  from orion.core.io.database.mongodb import MongoDB
  from orion.core.io.database.pickleddb import PickledDB
  from .conftest import insert_test_collection
label_desc: Use image node_id 6 for calling the TestRead obj's underlying member method code with example usage: obj.test_null_comp(orion_db) without return types