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from django.db.models.sql.compiler import ( # isort:skip
SQLAggregateCompiler,
SQLCompiler as BaseSQLCompiler,
SQLDeleteCompiler,
SQLInsertCompiler as BaseSQLInsertCompiler,
SQLUpdateCompiler,
)
__all__ = [
"SQLAggregateCompiler",
"SQLCompiler",
"SQLDeleteCompiler",
"SQLInsertCompiler",
"SQLUpdateCompiler",
]
class InsertUnnest(list):
"""
Sentinel value to signal DatabaseOperations.bulk_insert_sql() that the
UNNEST strategy should be used for the bulk insert.
"""
def __str__(self):
return "UNNEST(%s)" % ", ".join(self)
class SQLCompiler(BaseSQLCompiler):
def quote_name_unless_alias(self, name):
if "$" in name:
raise ValueError(
"Dollar signs are not permitted in column aliases on PostgreSQL."
)
return super().quote_name_unless_alias(name)
class SQLInsertCompiler(BaseSQLInsertCompiler):
def assemble_as_sql(self, fields, value_rows):
# Specialize bulk-insertion of literal values through UNNEST to
# reduce the time spent planning the query.
if (
# The optimization is not worth doing if there is a single
# row as it will result in the same number of placeholders.
len(value_rows) <= 1
# Lack of fields denote the usage of the DEFAULT keyword
# for the insertion of empty rows.
or any(field is None for field in fields)
# Field.get_placeholder takes value as an argument, so the
# resulting placeholder might be dependent on the value.
# in UNNEST requires a single placeholder to "fit all values" in
# the array.
or any(hasattr(field, "get_placeholder") for field in fields)
# Fields that don't use standard internal types might not be
# unnest'able (e.g. array and geometry types are known to be
# problematic).
or any(
(field.target_field if field.is_relation else field).get_internal_type()
not in self.connection.data_types
for field in fields
)
# Compilable cannot be combined in an array of literal values.
or any(any(hasattr(value, "as_sql") for value in row) for row in value_rows)
):
return super().assemble_as_sql(fields, value_rows)
# Manually remove parameters from `db_type` to ensure no data
# truncation takes place (e.g. varchar[] instead of varchar(50)[]).
db_types = [field.db_type(self.connection).split("(")[0] for field in fields]
return InsertUnnest(["(%%s)::%s[]" % db_type for db_type in db_types]), [
list(map(list, zip(*value_rows)))
]
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