def q_mentioned_fields(q, model):
"""Returns list of field names mentioned in Q object.
Q(a__isnull=True, b=F('c')) -> ['a', 'b', 'c']
"""
query = Query(model)
where = query._add_q(q, used_aliases=set(), allow_joins=False)[0]
return list(sorted(set(expression_mentioned_fields(where))))
def q_to_sql(q, model, schema_editor):
# Q -> SQL conversion based on code from Ian Foote's Check Constraints pull request:
# https://github.com/django/django/pull/7615/
query = Query(model)
where = query._add_q(q, used_aliases=set(), allow_joins=False)[0]
connection = schema_editor.connection
compiler = connection.ops.compiler('SQLCompiler')(query, connection,
'default')
sql, params = where.as_sql(compiler, connection)
params = tuple(map(schema_editor.quote_value, params))
where_sql = sql % params
return where_sql
