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_rename_table(self):
"""
Test renaming a table.
"""
name_column = Varchar()
name_column._meta.name = "name"
schema: t.List[DiffableTable] = [
DiffableTable(
class_name="Act", tablename="act", columns=[name_column]
)
]
schema_snapshot: t.List[DiffableTable] = [
DiffableTable(
class_name="Band", tablename="band", columns=[name_column]
)
]
schema_differ = SchemaDiffer(
schema=schema, schema_snapshot=schema_snapshot, auto_input="y"
)
self.assertTrue(len(schema_differ.rename_tables.statements) == 1)
self.assertEqual(
schema_differ.rename_tables.statements[0],
"manager.rename_table(old_class_name='Band', old_tablename='band', new_class_name='Act', new_tablename='act')", # noqa
)
self.assertEqual(schema_differ.create_tables.statements, [])
self.assertEqual(schema_differ.drop_tables.statements, [])
def test_add_column(self):
"""
Test adding a column to an existing table.
"""
name_column = Varchar()
name_column._meta.name = "name"
genre_column = Varchar()
genre_column._meta.name = "genre"
schema: t.List[DiffableTable] = [
DiffableTable(
class_name="Band",
tablename="band",
columns=[name_column, genre_column],
)
]
schema_snapshot: t.List[DiffableTable] = [
DiffableTable(
class_name="Band",
tablename="band",
columns=[name_column],
)
]
schema_differ = SchemaDiffer(
schema=schema, schema_snapshot=schema_snapshot, auto_input="y"
)
self.assertTrue(len(schema_differ.add_columns.statements) == 1)
self.assertEqual(
schema_differ.add_columns.statements[0],
"manager.add_column(table_class_name='Band', tablename='band', column_name='genre', db_column_name='genre', column_class_name='Varchar', column_class=Varchar, params={'length': 255, 'default': '', 'null': False, 'primary_key': False, 'unique': False, 'index': False, 'index_method': IndexMethod.btree, 'choices': None, 'db_column_name': None, 'secret': False})", # noqa
)
def test_alter_column_precision(self):
price_1 = Numeric(digits=(4, 2))
price_1._meta.name = "price"
price_2 = Numeric(digits=(5, 2))
price_2._meta.name = "price"
schema: t.List[DiffableTable] = [
DiffableTable(
class_name="Ticket",
tablename="ticket",
columns=[price_1],
)
]
schema_snapshot: t.List[DiffableTable] = [
DiffableTable(
class_name="Ticket",
tablename="ticket",
columns=[price_2],
)
]
schema_differ = SchemaDiffer(
schema=schema, schema_snapshot=schema_snapshot, auto_input="y"
)
self.assertTrue(len(schema_differ.alter_columns.statements) == 1)
self.assertEqual(
schema_differ.alter_columns.statements[0],
"manager.alter_column(table_class_name='Ticket', tablename='ticket', column_name='price', params={'digits': (4, 2)}, old_params={'digits': (5, 2)}, column_class=Numeric, old_column_class=Numeric)", # noqa
)
def test_rename_column(self):
"""
Test renaming a column in an existing table.
"""
name_column = Varchar()
name_column._meta.name = "name"
title_column = Varchar()
title_column._meta.name = "title"
schema: t.List[DiffableTable] = [
DiffableTable(
class_name="Band",
tablename="band",
columns=[name_column],
)
]
schema_snapshot: t.List[DiffableTable] = [
DiffableTable(
class_name="Band",
tablename="band",
columns=[title_column],
)
]
schema_differ = SchemaDiffer(
schema=schema, schema_snapshot=schema_snapshot, auto_input="y"
)
self.assertTrue(len(schema_differ.rename_columns.statements) == 1)
self.assertEqual(
schema_differ.rename_columns.statements[0],
"manager.rename_column(table_class_name='Band', tablename='band', old_column_name='title', new_column_name='name', old_db_column_name='title', new_db_column_name='name')", # noqa
)
def test_drop_column(self):
"""
Test dropping a column from an existing table.
"""
name_column = Varchar()
name_column._meta.name = "name"
genre_column = Varchar()
genre_column._meta.name = "genre"
schema: t.List[DiffableTable] = [
DiffableTable(
class_name="Band",
tablename="band",
columns=[name_column],
)
]
schema_snapshot: t.List[DiffableTable] = [
DiffableTable(
class_name="Band",
tablename="band",
columns=[name_column, genre_column],
)
]
schema_differ = SchemaDiffer(
schema=schema, schema_snapshot=schema_snapshot, auto_input="y"
)
self.assertTrue(len(schema_differ.drop_columns.statements) == 1)
self.assertEqual(
schema_differ.drop_columns.statements[0],
"manager.drop_column(table_class_name='Band', tablename='band', column_name='genre', db_column_name='genre')", # noqa
)
def test_add_table(self):
"""
Test adding a new table.
"""
name_column = Varchar()
name_column._meta.name = "name"
schema: t.List[DiffableTable] = [
DiffableTable(class_name="Band",
tablename="band",
columns=[name_column])
]
schema_snapshot: t.List[DiffableTable] = []
schema_differ = SchemaDiffer(schema=schema,
schema_snapshot=schema_snapshot,
auto_input="y")
create_tables = schema_differ.create_tables
self.assertTrue(len(create_tables.statements) == 1)
self.assertEqual(
create_tables.statements[0],
"manager.add_table('Band', tablename='band')",
)
new_table_columns = schema_differ.new_table_columns
self.assertTrue(len(new_table_columns.statements) == 1)
self.assertEqual(
new_table_columns.statements[0],
"manager.add_column(table_class_name='Band', tablename='band', column_name='name', column_class_name='Varchar', column_class=Varchar, params={'length': 255, 'default': '', 'null': False, 'primary': False, 'key': False, 'unique': False, 'index': False, 'index_method': IndexMethod.btree})", # noqa
)
def test_drop_table(self):
"""
Test dropping an existing table.
"""
schema: t.List[DiffableTable] = []
schema_snapshot: t.List[DiffableTable] = [
DiffableTable(class_name="Band", tablename="band", columns=[])
]
schema_differ = SchemaDiffer(
schema=schema, schema_snapshot=schema_snapshot, auto_input="y"
)
self.assertTrue(len(schema_differ.drop_tables.statements) == 1)
self.assertEqual(
schema_differ.drop_tables.statements[0],
"manager.drop_table(class_name='Band', tablename='band')",
)