Repoint ForeignKeys when their to= changes. (a92bae0f) · Commits · Dom Sekotill / django

django/db/backends/postgresql_psycopg2/introspection.py

+1 −1

Original line number	Diff line number	Diff line
		@@ -118,7 +118,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
		"columns": set(),
		"primary_key": kind.lower() == "primary key",
		"unique": kind.lower() in ["primary key", "unique"],
		"foreign_key": set([tuple(x.split(".", 1)) for x in used_cols]) if kind.lower() == "foreign key" else None,
		"foreign_key": tuple(used_cols[0].split(".", 1)) if kind.lower() == "foreign key" else None,
		"check": False,
		"index": False,
		}

django/db/backends/schema.py

+30 −2

Original line number	Diff line number	Diff line
		@@ -21,7 +21,6 @@ class BaseDatabaseSchemaEditor(object):
		commit() is called.

		TODO:
		- Repointing of FKs
		- Repointing of M2Ms
		- Check constraints (PosIntField)
		"""
		@@ -401,6 +400,22 @@ class BaseDatabaseSchemaEditor(object):
		"name": index_name,
		}
		)
		# Drop any FK constraints, we'll remake them later
		if getattr(old_field, "rel"):
		fk_names = self._constraint_names(model, [old_field.column], foreign_key=True)
		if strict and len(fk_names) != 1:
		raise ValueError("Found wrong number (%s) of foreign key constraints for %s.%s" % (
		len(fk_names),
		model._meta.db_table,
		old_field.column,
		))
		for fk_name in fk_names:
		self.execute(
		self.sql_delete_fk % {
		"table": self.quote_name(model._meta.db_table),
		"name": fk_name,
		}
		)
		# Have they renamed the column?
		if old_field.column != new_field.column:
		self.execute(self.sql_rename_column % {
		@@ -516,6 +531,17 @@ class BaseDatabaseSchemaEditor(object):
		"columns": self.quote_name(new_field.column),
		}
		)
		# Does it have a foreign key?
		if getattr(new_field, "rel"):
		self.execute(
		self.sql_create_fk % {
		"table": self.quote_name(model._meta.db_table),
		"name": self._create_index_name(model, [new_field.column], suffix="_fk"),
		"column": self.quote_name(new_field.column),
		"to_table": self.quote_name(new_field.rel.to._meta.db_table),
		"to_column": self.quote_name(new_field.rel.get_related_field().column),
		}
		)

		def _type_for_alter(self, field):
		"""
		@@ -543,7 +569,7 @@ 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=None, unique=None, primary_key=None, index=None):
		def _constraint_names(self, model, column_names=None, unique=None, primary_key=None, index=None, foreign_key=None):
		"Returns all constraint names matching the columns and conditions"
		column_names = set(column_names) if column_names else None
		constraints = self.connection.introspection.get_constraints(self.connection.cursor(), model._meta.db_table)
		@@ -556,5 +582,7 @@ class BaseDatabaseSchemaEditor(object):
		continue
		if index is not None and infodict['index'] != index:
		continue
		if foreign_key is not None and not infodict['foreign_key']:
		continue
		result.append(name)
		return result

tests/modeltests/schema/tests.py

+25 −4

Original line number	Diff line number	Diff line
		@@ -5,7 +5,7 @@ from django.test import TestCase
		from django.utils.unittest import skipUnless
		from django.db import connection, DatabaseError, IntegrityError
		from django.db.models.fields import IntegerField, TextField, CharField, SlugField
		from django.db.models.fields.related import ManyToManyField
		from django.db.models.fields.related import ManyToManyField, ForeignKey
		from django.db.models.loading import cache
		from .models import Author, Book, BookWithSlug, AuthorWithM2M, Tag, TagUniqueRename, UniqueTest

		@@ -114,15 +114,16 @@ class SchemaTests(TestCase):
		)

		@skipUnless(connection.features.supports_foreign_keys, "No FK support")
		def test_creation_fk(self):
		"Tests that creating tables out of FK order works"
		def test_fk(self):
		"Tests that creating tables out of FK order, then repointing, works"
		# Create the table
		editor = connection.schema_editor()
		editor.start()
		editor.create_model(Book)
		editor.create_model(Author)
		editor.create_model(Tag)
		editor.commit()
		# Check that both tables are there
		# Check that initial tables are there
		try:
		list(Author.objects.all())
		except DatabaseError, e:
		@@ -139,6 +140,26 @@ class SchemaTests(TestCase):
		pub_date = datetime.datetime.now(),
		)
		connection.commit()
		# Repoint the FK constraint
		new_field = ForeignKey(Tag)
		new_field.set_attributes_from_name("author")
		editor = connection.schema_editor()
		editor.start()
		editor.alter_field(
		Book,
		Book._meta.get_field_by_name("author")[0],
		new_field,
		strict=True,
		)
		editor.commit()
		# Make sure the new FK constraint is present
		constraints = connection.introspection.get_constraints(connection.cursor(), Book._meta.db_table)
		for name, details in constraints.items():
		if details['columns'] == set(["author_id"]) and details['foreign_key']:
		self.assertEqual(details['foreign_key'], ('schema_tag', 'id'))
		break
		else:
		self.fail("No FK constraint for author_id found")

		def test_create_field(self):
		"""