def count(cls, transaction: Optional[spanner_transaction.Transaction],
*conditions: condition.Condition) -> int:
"""Returns the number of objects in Spanner that match the given conditions.
Args:
transaction: The existing transaction to use, or None to start a new
transaction
*conditions: Instances of subclasses of Condition that help specify which
rows should be included in the count. The includes condition is not
allowed here
Returns:
The integer result of the COUNT query
"""
builder = query.CountQuery(cls, conditions)
args = [builder.sql(), builder.parameters(), builder.types()]
results = cls._execute_read(table_apis.sql_query, transaction, args)
return builder.process_results(results)
def test_count_only_allows_where_and_from_segment_conditions(
self, condition):
with self.assertRaises(error.SpannerError):
query.CountQuery(models.UnittestModel, [condition])
def test_count_allows_force_index(self):
force_index = condition.force_index('test_index')
count_query = query.CountQuery(models.UnittestModel, [force_index])
sql = count_query.sql()
expected_sql = 'SELECT COUNT(*) FROM table@{FORCE_INDEX=test_index}'
self.assertEqual(expected_sql, sql)