from django.core.exceptions import FieldError
from django.db.models.expressions import Col
from django.db.models.sql import compiler
class SQLCompiler(compiler.SQLCompiler):
def as_subquery_condition(self, alias, columns, compiler):
qn = compiler.quote_name_unless_alias
qn2 = self.connection.ops.quote_name
sql, params = self.as_sql()
return '(%s) IN (%s)' % (', '.join('%s.%s' % (qn(alias), qn2(column)) for column in columns), sql), params
class SQLInsertCompiler(compiler.SQLInsertCompiler, SQLCompiler):
pass
class SQLDeleteCompiler(compiler.SQLDeleteCompiler, SQLCompiler):
def as_sql(self):
# Prefer the non-standard DELETE FROM syntax over the SQL generated by
# the SQLDeleteCompiler's default implementation when multiple tables
# are involved since MySQL/MariaDB will generate a more efficient query
# plan than when using a subquery.
where, having = self.query.where.split_having()
if self.single_alias or having:
# DELETE FROM cannot be used when filtering against aggregates
# since it doesn't allow for GROUP BY and HAVING clauses.
return super().as_sql()
result = [
'DELETE %s FROM' % self.quote_name_unless_alias(
self.query.get_initial_alias()
)
]
from_sql, from_params = self.get_from_clause()
result.extend(from_sql)
where_sql, where_params = self.compile(where)
if where_sql:
result.append('WHERE %s' % where_sql)
return ' '.join(result), tuple(from_params) + tuple(where_params)
class SQLUpdateCompiler(compiler.SQLUpdateCompiler, SQLCompiler):
def as_sql(self):
update_query, update_params = super().as_sql()
# MySQL and MariaDB support UPDATE ... ORDER BY syntax.
if self.query.order_by:
order_by_sql = []
order_by_params = []
db_table = self.query.get_meta().db_table
try:
for resolved, (sql, params, _) in self.get_order_by():
if (
isinstance(resolved.expression, Col) and
resolved.expression.alias != db_table
):
# Ignore ordering if it contains joined fields, because
# they cannot be used in the ORDER BY clause.
raise FieldError
order_by_sql.append(sql)
order_by_params.extend(params)
update_query += ' ORDER BY ' + ', '.join(order_by_sql)
update_params += tuple(order_by_params)
except FieldError:
# Ignore ordering if it contains annotations, because they're
# removed in .update() and cannot be resolved.
pass
return update_query, update_params
class SQLAggregateCompiler(compiler.SQLAggregateCompiler, SQLCompiler):
pass