97 lines
3.4 KiB
Python
97 lines
3.4 KiB
Python
from __future__ import print_function
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import uuid
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from django.db.backends.util import truncate_name
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from south.db import generic
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class DatabaseOperations(generic.DatabaseOperations):
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"""
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PsycoPG2 implementation of database operations.
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"""
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backend_name = "postgres"
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def create_index_name(self, table_name, column_names, suffix=""):
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"""
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Generate a unique name for the index
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Django's logic for naming field indexes is different in the
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postgresql_psycopg2 backend, so we follow that for single-column
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indexes.
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"""
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if len(column_names) == 1:
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return truncate_name(
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'%s_%s%s' % (table_name, column_names[0], suffix),
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self._get_connection().ops.max_name_length()
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)
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return super(DatabaseOperations, self).create_index_name(table_name, column_names, suffix)
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@generic.copy_column_constraints
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@generic.delete_column_constraints
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def rename_column(self, table_name, old, new):
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if old == new:
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# Short-circuit out
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return []
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self.execute('ALTER TABLE %s RENAME COLUMN %s TO %s;' % (
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self.quote_name(table_name),
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self.quote_name(old),
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self.quote_name(new),
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))
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@generic.invalidate_table_constraints
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def rename_table(self, old_table_name, table_name):
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"will rename the table and an associated ID sequence and primary key index"
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# First, rename the table
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generic.DatabaseOperations.rename_table(self, old_table_name, table_name)
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# Then, try renaming the ID sequence
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# (if you're using other AutoFields... your problem, unfortunately)
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if self.execute(
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"""
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SELECT 1
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FROM information_schema.sequences
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WHERE sequence_name = %s
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""",
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[old_table_name + '_id_seq']
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):
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generic.DatabaseOperations.rename_table(self, old_table_name + "_id_seq", table_name + "_id_seq")
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# Rename primary key index, will not rename other indices on
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# the table that are used by django (e.g. foreign keys). Until
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# figure out how, you need to do this yourself.
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pkey_index_names = self.execute(
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"""
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SELECT pg_index.indexrelid::regclass
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FROM pg_index, pg_attribute
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WHERE
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indrelid = %s::regclass AND
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pg_attribute.attrelid = indrelid AND
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pg_attribute.attnum = any(pg_index.indkey)
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AND indisprimary
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""",
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[table_name]
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)
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if old_table_name + "_pkey" in pkey_index_names:
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generic.DatabaseOperations.rename_table(self, old_table_name + "_pkey", table_name + "_pkey")
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def rename_index(self, old_index_name, index_name):
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"Rename an index individually"
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generic.DatabaseOperations.rename_table(self, old_index_name, index_name)
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def _default_value_workaround(self, value):
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"Support for UUIDs on psql"
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if isinstance(value, uuid.UUID):
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return str(value)
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else:
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return super(DatabaseOperations, self)._default_value_workaround(value)
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def _db_type_for_alter_column(self, field):
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return self._db_positive_type_for_alter_column(DatabaseOperations, field)
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def _alter_add_column_mods(self, field, name, params, sqls):
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return self._alter_add_positive_check(DatabaseOperations, field, name, params, sqls)
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