72 lines
3 KiB
Python
72 lines
3 KiB
Python
from django.core.exceptions import FieldError, FullResultSet
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from django.db.models.expressions import Col
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from django.db.models.sql.compiler import SQLAggregateCompiler, SQLCompiler
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from django.db.models.sql.compiler import SQLDeleteCompiler as BaseSQLDeleteCompiler
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from django.db.models.sql.compiler import SQLInsertCompiler
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from django.db.models.sql.compiler import SQLUpdateCompiler as BaseSQLUpdateCompiler
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__all__ = [
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"SQLAggregateCompiler",
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"SQLCompiler",
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"SQLDeleteCompiler",
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"SQLInsertCompiler",
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"SQLUpdateCompiler",
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]
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class SQLDeleteCompiler(BaseSQLDeleteCompiler):
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def as_sql(self):
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# Prefer the non-standard DELETE FROM syntax over the SQL generated by
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# the SQLDeleteCompiler's default implementation when multiple tables
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# are involved since MySQL/MariaDB will generate a more efficient query
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# plan than when using a subquery.
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where, having, qualify = self.query.where.split_having_qualify(
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must_group_by=self.query.group_by is not None
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)
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if self.single_alias or having or qualify:
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# DELETE FROM cannot be used when filtering against aggregates or
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# window functions as it doesn't allow for GROUP BY/HAVING clauses
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# and the subquery wrapping (necessary to emulate QUALIFY).
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return super().as_sql()
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result = [
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"DELETE %s FROM"
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% self.quote_name_unless_alias(self.query.get_initial_alias())
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]
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from_sql, params = self.get_from_clause()
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result.extend(from_sql)
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try:
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where_sql, where_params = self.compile(where)
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except FullResultSet:
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pass
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else:
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result.append("WHERE %s" % where_sql)
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params.extend(where_params)
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return " ".join(result), tuple(params)
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class SQLUpdateCompiler(BaseSQLUpdateCompiler):
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def as_sql(self):
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update_query, update_params = super().as_sql()
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# MySQL and MariaDB support UPDATE ... ORDER BY syntax.
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if self.query.order_by:
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order_by_sql = []
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order_by_params = []
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db_table = self.query.get_meta().db_table
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try:
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for resolved, (sql, params, _) in self.get_order_by():
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if (
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isinstance(resolved.expression, Col)
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and resolved.expression.alias != db_table
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):
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# Ignore ordering if it contains joined fields, because
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# they cannot be used in the ORDER BY clause.
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raise FieldError
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order_by_sql.append(sql)
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order_by_params.extend(params)
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update_query += " ORDER BY " + ", ".join(order_by_sql)
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update_params += tuple(order_by_params)
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except FieldError:
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# Ignore ordering if it contains annotations, because they're
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# removed in .update() and cannot be resolved.
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pass
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return update_query, update_params
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