Implement primary key changing (cd583d6d) · Commits · Dom Sekotill / django

django/db/backends/mysql/introspection.py

+6 −1

Original line number	Diff line number	Diff line
		@@ -99,7 +99,12 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
		for row in rows:
		if row[2] in multicol_indexes:
		continue
		indexes[row[4]] = {'primary_key': (row[2] == 'PRIMARY'), 'unique': not bool(row[1])}
		if row[4] not in indexes:
		indexes[row[4]] = {'primary_key': False, 'unique': False}
		if row[2] == 'PRIMARY':
		indexes[row[4]]['primary_key'] = True
		if not bool(row[1]):
		indexes[row[4]]['unique'] = True
		return indexes

		def get_constraints(self, cursor, table_name):

django/db/backends/mysql/schema.py

+3 −0

Original line number	Diff line number	Diff line
		@@ -21,3 +21,6 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):

		alter_string_set_null = 'MODIFY %(column)s %(type)s NULL;'
		alter_string_drop_null = 'MODIFY %(column)s %(type)s NOT NULL;'

		sql_create_pk = "ALTER TABLE %(table)s ADD CONSTRAINT %(name)s PRIMARY KEY (%(columns)s)"
		sql_delete_pk = "ALTER TABLE %(table)s DROP PRIMARY KEY"

django/db/backends/schema.py

+35 −10

Original line number	Diff line number	Diff line
		@@ -24,8 +24,6 @@ class BaseDatabaseSchemaEditor(object):
		- Repointing of FKs
		- Repointing of M2Ms
		- Check constraints (PosIntField)
		- PK changing
		- db_index on alter field
		"""

		# Overrideable SQL templates
		@@ -57,8 +55,8 @@ class BaseDatabaseSchemaEditor(object):
		sql_create_index = "CREATE INDEX %(name)s ON %(table)s (%(columns)s)%(extra)s;"
		sql_delete_index = "DROP INDEX %(name)s"

		sql_create_pk = "ALTER TABLE %(table)s ADD CONSTRAINT %(constraint)s PRIMARY KEY (%(columns)s)"
		sql_delete_pk = "ALTER TABLE %(table)s DROP CONSTRAINT %(constraint)s"
		sql_create_pk = "ALTER TABLE %(table)s ADD CONSTRAINT %(name)s PRIMARY KEY (%(columns)s)"
		sql_delete_pk = "ALTER TABLE %(table)s DROP CONSTRAINT %(name)s"

		def __init__(self, connection):
		self.connection = connection
		@@ -135,9 +133,10 @@ class BaseDatabaseSchemaEditor(object):
		elif field.unique:
		sql += " UNIQUE"
		# If we were told to include a default value, do so
		if include_default:
		default_value = self.effective_default(field)
		if include_default and default_value is not None:
		sql += " DEFAULT %s"
		params += [self.effective_default(field)]
		params += [default_value]
		# Return the sql
		return sql, params

		@@ -491,6 +490,32 @@ class BaseDatabaseSchemaEditor(object):
		"extra": "",
		}
		)
		# Changed to become primary key?
		# Note that we don't detect unsetting of a PK, as we assume another field
		# will always come along and replace it.
		if not old_field.primary_key and new_field.primary_key:
		# First, drop the old PK
		constraint_names = self._constraint_names(model, primary_key=True)
		if strict and len(constraint_names) != 1:
		raise ValueError("Found wrong number (%s) of PK constraints for %s" % (
		len(constraint_names),
		model._meta.db_table,
		))
		for constraint_name in constraint_names:
		self.execute(
		self.sql_delete_pk % {
		"table": self.quote_name(model._meta.db_table),
		"name": constraint_name,
		},
		)
		# Make the new one
		self.execute(
		self.sql_create_pk % {
		"table": self.quote_name(model._meta.db_table),
		"name": self._create_index_name(model, [new_field.column], suffix="_pk"),
		"columns": self.quote_name(new_field.column),
		}
		)

		def _type_for_alter(self, field):
		"""
		@@ -518,16 +543,16 @@ class BaseDatabaseSchemaEditor(object):
		index_name = '%s%s' % (table_name[:(self.connection.features.max_index_name_length - len(part))], part)
		return index_name

		def _constraint_names(self, model, column_names, unique=None, primary_key=None, index=None):
		def _constraint_names(self, model, column_names=None, unique=None, primary_key=None, index=None):
		"Returns all constraint names matching the columns and conditions"
		column_names = set(column_names)
		column_names = set(column_names) if column_names else None
		constraints = self.connection.introspection.get_constraints(self.connection.cursor(), model._meta.db_table)
		result = []
		for name, infodict in constraints.items():
		if column_names == infodict['columns']:
		if column_names is None or column_names == infodict['columns']:
		if unique is not None and infodict['unique'] != unique:
		continue
		if primary_key is not None and infodict['primary_key'] != unique:
		if primary_key is not None and infodict['primary_key'] != primary_key:
		continue
		if index is not None and infodict['index'] != index:
		continue

tests/modeltests/schema/tests.py

+34 −0

Original line number	Diff line number	Diff line
		@@ -478,3 +478,37 @@ class SchemaTests(TestCase):
		"slug",
		connection.introspection.get_indexes(connection.cursor(), Book._meta.db_table),
		)

		def test_primary_key(self):
		"""
		Tests altering of the primary key
		"""
		# Create the table
		editor = connection.schema_editor()
		editor.start()
		editor.create_model(Tag)
		editor.commit()
		# Ensure the table is there and has the right PK
		self.assertTrue(
		connection.introspection.get_indexes(connection.cursor(), Tag._meta.db_table)['id']['primary_key'],
		)
		# Alter to change the PK
		new_field = SlugField(primary_key=True)
		new_field.set_attributes_from_name("slug")
		editor = connection.schema_editor()
		editor.start()
		editor.delete_field(Tag, Tag._meta.get_field_by_name("id")[0])
		editor.alter_field(
		Tag,
		Tag._meta.get_field_by_name("slug")[0],
		new_field,
		)
		editor.commit()
		# Ensure the PK changed
		self.assertNotIn(
		'id',
		connection.introspection.get_indexes(connection.cursor(), Tag._meta.db_table),
		)
		self.assertTrue(
		connection.introspection.get_indexes(connection.cursor(), Tag._meta.db_table)['slug']['primary_key'],
		)