135 lines
6.3 KiB
Python
135 lines
6.3 KiB
Python
import psycopg2
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from django.db.backends.base.schema import BaseDatabaseSchemaEditor
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class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
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sql_alter_column_type = "ALTER COLUMN %(column)s TYPE %(type)s USING %(column)s::%(type)s"
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sql_create_sequence = "CREATE SEQUENCE %(sequence)s"
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sql_delete_sequence = "DROP SEQUENCE IF EXISTS %(sequence)s CASCADE"
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sql_set_sequence_max = "SELECT setval('%(sequence)s', MAX(%(column)s)) FROM %(table)s"
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sql_create_index = "CREATE INDEX %(name)s ON %(table)s%(using)s (%(columns)s)%(extra)s"
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sql_create_varchar_index = "CREATE INDEX %(name)s ON %(table)s (%(columns)s varchar_pattern_ops)%(extra)s"
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sql_create_text_index = "CREATE INDEX %(name)s ON %(table)s (%(columns)s text_pattern_ops)%(extra)s"
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sql_delete_index = "DROP INDEX IF EXISTS %(name)s"
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# Setting the constraint to IMMEDIATE runs any deferred checks to allow
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# dropping it in the same transaction.
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sql_delete_fk = "SET CONSTRAINTS %(name)s IMMEDIATE; ALTER TABLE %(table)s DROP CONSTRAINT %(name)s"
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sql_delete_procedure = 'DROP FUNCTION %(procedure)s(%(param_types)s)'
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def quote_value(self, value):
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return psycopg2.extensions.adapt(value)
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def _field_indexes_sql(self, model, field):
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output = super()._field_indexes_sql(model, field)
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like_index_statement = self._create_like_index_sql(model, field)
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if like_index_statement is not None:
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output.append(like_index_statement)
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return output
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def _create_like_index_sql(self, model, field):
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"""
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Return the statement to create an index with varchar operator pattern
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when the column type is 'varchar' or 'text', otherwise return None.
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"""
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db_type = field.db_type(connection=self.connection)
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if db_type is not None and (field.db_index or field.unique):
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# Fields with database column types of `varchar` and `text` need
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# a second index that specifies their operator class, which is
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# needed when performing correct LIKE queries outside the
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# C locale. See #12234.
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#
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# The same doesn't apply to array fields such as varchar[size]
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# and text[size], so skip them.
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if '[' in db_type:
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return None
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if db_type.startswith('varchar'):
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return self._create_index_sql(model, [field], suffix='_like', sql=self.sql_create_varchar_index)
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elif db_type.startswith('text'):
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return self._create_index_sql(model, [field], suffix='_like', sql=self.sql_create_text_index)
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return None
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def _alter_column_type_sql(self, model, old_field, new_field, new_type):
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"""Make ALTER TYPE with SERIAL make sense."""
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table = model._meta.db_table
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if new_type.lower() in ("serial", "bigserial"):
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column = new_field.column
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sequence_name = "%s_%s_seq" % (table, column)
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col_type = "integer" if new_type.lower() == "serial" else "bigint"
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return (
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(
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self.sql_alter_column_type % {
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"column": self.quote_name(column),
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"type": col_type,
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},
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[],
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),
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[
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(
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self.sql_delete_sequence % {
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"sequence": self.quote_name(sequence_name),
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},
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[],
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),
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(
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self.sql_create_sequence % {
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"sequence": self.quote_name(sequence_name),
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},
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[],
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),
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(
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self.sql_alter_column % {
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"table": self.quote_name(table),
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"changes": self.sql_alter_column_default % {
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"column": self.quote_name(column),
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"default": "nextval('%s')" % self.quote_name(sequence_name),
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}
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},
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[],
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),
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(
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self.sql_set_sequence_max % {
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"table": self.quote_name(table),
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"column": self.quote_name(column),
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"sequence": self.quote_name(sequence_name),
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},
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[],
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),
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],
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)
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else:
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return super()._alter_column_type_sql(model, old_field, new_field, new_type)
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def _alter_field(self, model, old_field, new_field, old_type, new_type,
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old_db_params, new_db_params, strict=False):
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# Drop indexes on varchar/text/citext columns that are changing to a
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# different type.
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if (old_field.db_index or old_field.unique) and (
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(old_type.startswith('varchar') and not new_type.startswith('varchar')) or
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(old_type.startswith('text') and not new_type.startswith('text')) or
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(old_type.startswith('citext') and not new_type.startswith('citext'))
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):
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index_name = self._create_index_name(model._meta.db_table, [old_field.column], suffix='_like')
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self.execute(self._delete_constraint_sql(self.sql_delete_index, model, index_name))
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super()._alter_field(
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model, old_field, new_field, old_type, new_type, old_db_params,
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new_db_params, strict,
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)
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# Added an index? Create any PostgreSQL-specific indexes.
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if ((not (old_field.db_index or old_field.unique) and new_field.db_index) or
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(not old_field.unique and new_field.unique)):
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like_index_statement = self._create_like_index_sql(model, new_field)
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if like_index_statement is not None:
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self.execute(like_index_statement)
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# Removed an index? Drop any PostgreSQL-specific indexes.
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if old_field.unique and not (new_field.db_index or new_field.unique):
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index_to_remove = self._create_index_name(model._meta.db_table, [old_field.column], suffix='_like')
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self.execute(self._delete_constraint_sql(self.sql_delete_index, model, index_to_remove))
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