async def get_alter_statements(
self, app_config: AppConfig) -> t.List[AlterStatements]:
"""
Works out which alter statements are required.
"""
migration_managers = await self.get_migration_managers(
app_config=app_config)
schema_snapshot = SchemaSnapshot(migration_managers)
snapshot = schema_snapshot.get_snapshot()
# Now get the current schema:
current_diffable_tables = [
DiffableTable(
class_name=i.__name__,
tablename=i._meta.tablename,
columns=i._meta.non_default_columns,
) for i in app_config.table_classes
]
# Compare the current schema with the snapshot
differ = SchemaDiffer(
schema=current_diffable_tables,
schema_snapshot=snapshot,
auto_input=self.auto_input,
)
return differ.get_alter_statements()
def test_alter_column(self):
"""
Test altering columns.
"""
manager_1 = MigrationManager()
manager_1.add_table(class_name="Manager", tablename="manager")
manager_1.add_column(
table_class_name="Manager",
tablename="manager",
column_name="name",
column_class_name="Varchar",
params={"length": 100},
)
manager_2 = MigrationManager()
manager_2.alter_column(
table_class_name="Manager",
tablename="manager",
column_name="name",
params={"unique": True},
old_params={"unique": False},
)
schema_snapshot = SchemaSnapshot(managers=[manager_1, manager_2])
snapshot = schema_snapshot.get_snapshot()
self.assertTrue(snapshot[0].columns[0]._meta.unique)
def test_get_table_from_snapshot(self):
manager_1 = MigrationManager()
manager_1.add_table(class_name="Manager", tablename="manager")
manager_1.add_table(class_name="Band", tablename="band")
schema_snapshot = SchemaSnapshot(managers=[manager_1])
table = schema_snapshot.get_table_from_snapshot("Manager")
self.assertTrue(table.class_name == "Manager")
with self.assertRaises(ValueError):
schema_snapshot.get_table_from_snapshot("Foo")
def test_add_table(self):
"""
Test adding tables.
"""
manager_1 = MigrationManager()
manager_1.add_table(class_name="Manager", tablename="manager")
manager_2 = MigrationManager()
manager_2.add_table(class_name="Band", tablename="band")
schema_snapshot = SchemaSnapshot(managers=[manager_1, manager_2])
snapshot = schema_snapshot.get_snapshot()
self.assertTrue(len(snapshot) == 2)
class_names = [i.class_name for i in snapshot]
self.assertTrue("Band" in class_names)
self.assertTrue("Manager" in class_names)
def test_add_column(self):
"""
Test adding columns.
"""
manager = MigrationManager()
manager.add_table(class_name="Manager", tablename="manager")
manager.add_column(
table_class_name="Manager",
tablename="manager",
column_name="name",
column_class_name="Varchar",
params={"length": 100},
)
schema_snapshot = SchemaSnapshot(managers=[manager])
snapshot = schema_snapshot.get_snapshot()
self.assertTrue(len(snapshot) == 1)
self.assertTrue(len(snapshot[0].columns) == 1)
def test_rename_table(self):
"""
Test renaming tables.
"""
manager_1 = MigrationManager()
manager_1.add_table(class_name="Band", tablename="band")
manager_2 = MigrationManager()
manager_2.rename_table(
old_class_name="Band",
old_tablename="band",
new_class_name="Performer",
new_tablename="performer",
)
schema_snapshot = SchemaSnapshot(managers=[manager_1, manager_2])
snapshot = schema_snapshot.get_snapshot()
self.assertTrue(snapshot[0].class_name == "Performer")
self.assertTrue(snapshot[0].tablename == "performer")
def test_drop_column(self):
"""
Test dropping columns.
"""
manager_1 = MigrationManager()
manager_1.add_table(class_name="Manager", tablename="manager")
manager_1.add_column(
table_class_name="Manager",
tablename="manager",
column_name="name",
column_class_name="Varchar",
params={"length": 100},
)
manager_2 = MigrationManager()
manager_2.drop_column(
table_class_name="Manager", tablename="manager", column_name="name"
)
schema_snapshot = SchemaSnapshot(managers=[manager_1, manager_2])
snapshot = schema_snapshot.get_snapshot()
self.assertEqual(len(snapshot[0].columns), 0)
def test_rename_column(self):
"""
Test renaming columns.
"""
manager_1 = MigrationManager()
manager_1.add_table(class_name="Manager", tablename="manager")
manager_1.add_column(
table_class_name="Manager",
tablename="manager",
column_name="name",
column_class_name="Varchar",
params={"length": 100},
)
manager_2 = MigrationManager()
manager_2.rename_column(
table_class_name="Manager",
tablename="manager",
old_column_name="name",
new_column_name="title",
)
schema_snapshot = SchemaSnapshot(managers=[manager_1, manager_2])
snapshot = schema_snapshot.get_snapshot()
self.assertTrue(snapshot[0].columns[0]._meta.name == "title")
# Make sure double renames still work
manager_3 = MigrationManager()
manager_3.rename_column(
table_class_name="Manager",
tablename="manager",
old_column_name="title",
new_column_name="label",
)
schema_snapshot = SchemaSnapshot(
managers=[manager_1, manager_2, manager_3]
)
snapshot = schema_snapshot.get_snapshot()
self.assertTrue(snapshot[0].columns[0]._meta.name == "label")