59 lines
2.1 KiB
Python
59 lines
2.1 KiB
Python
from django.db.backends.schema import BaseDatabaseSchemaEditor
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class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
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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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def _alter_column_type_sql(self, table, column, type):
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"""
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Makes ALTER TYPE with SERIAL make sense.
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"""
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if type.lower() == "serial":
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sequence_name = "%s_%s_seq" % (table, column)
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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": "integer",
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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": 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": 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": table,
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"changes": self.sql_alter_column_default % {
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"column": column,
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"default": "nextval('%s')" % 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": table,
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"column": column,
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"sequence": 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(DatabaseSchemaEditor, self)._alter_column_type_sql(table, column, type)
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