Add cascade delete to the 1 to composite relationships. (#1295)

caravel/models.py

@@ -40,7 +40,7 @@
 )
 from sqlalchemy.ext.compiler import compiles
 from sqlalchemy.ext.declarative import declared_attr
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import backref, relationship
 from sqlalchemy.sql import table, literal_column, text, column
 from sqlalchemy.sql.expression import ColumnClause, TextAsFrom
 from sqlalchemy_utils import EncryptedType
@@ -679,7 +679,9 @@ class SqlaTable(Model, Queryable, AuditMixinNullable):
     user_id = Column(Integer, ForeignKey('ab_user.id'))
     owner = relationship('User', backref='tables', foreign_keys=[user_id])
     database = relationship(
-        'Database', backref='tables', foreign_keys=[database_id])
+        'Database',
+        backref=backref('tables', cascade='all, delete-orphan'),
+        foreign_keys=[database_id])
     offset = Column(Integer, default=0)
     cache_timeout = Column(Integer)
     schema = Column(String(255))
@@ -1069,7 +1071,9 @@ class SqlMetric(Model, AuditMixinNullable):
     metric_type = Column(String(32))
     table_id = Column(Integer, ForeignKey('tables.id'))
     table = relationship(
-        'SqlaTable', backref='metrics', foreign_keys=[table_id])
+        'SqlaTable',
+        backref=backref('metrics', cascade='all, delete-orphan'),
+        foreign_keys=[table_id])
     expression = Column(Text)
     description = Column(Text)
     is_restricted = Column(Boolean, default=False, nullable=True)
@@ -1096,7 +1100,9 @@ class TableColumn(Model, AuditMixinNullable):
     id = Column(Integer, primary_key=True)
     table_id = Column(Integer, ForeignKey('tables.id'))
     table = relationship(
-        'SqlaTable', backref='columns', foreign_keys=[table_id])
+        'SqlaTable',
+        backref=backref('columns', cascade='all, delete-orphan'),
+        foreign_keys=[table_id])
     column_name = Column(String(255))
     verbose_name = Column(String(1024))
     is_dttm = Column(Boolean, default=False)
@@ -1242,7 +1248,10 @@ class DruidDatasource(Model, AuditMixinNullable, Queryable):
     description = Column(Text)
     default_endpoint = Column(Text)
     user_id = Column(Integer, ForeignKey('ab_user.id'))
-    owner = relationship('User', backref='datasources', foreign_keys=[user_id])
+    owner = relationship(
+        'User',
+        backref=backref('datasources', cascade='all, delete-orphan'),
+        foreign_keys=[user_id])
     cluster_name = Column(
         String(250), ForeignKey('clusters.cluster_name'))
     cluster = relationship(
@@ -1799,8 +1808,10 @@ class DruidMetric(Model, AuditMixinNullable):
         String(255),
         ForeignKey('datasources.datasource_name'))
     # Setting enable_typechecks=False disables polymorphic inheritance.
-    datasource = relationship('DruidDatasource', backref='metrics',
-                              enable_typechecks=False)
+    datasource = relationship(
+        'DruidDatasource',
+        backref=backref('metrics', cascade='all, delete-orphan'),
+        enable_typechecks=False)
     json = Column(Text)
     description = Column(Text)
     is_restricted = Column(Boolean, default=False, nullable=True)
@@ -1833,8 +1844,10 @@ class DruidColumn(Model, AuditMixinNullable):
         String(255),
         ForeignKey('datasources.datasource_name'))
     # Setting enable_typechecks=False disables polymorphic inheritance.
-    datasource = relationship('DruidDatasource', backref='columns',
-                              enable_typechecks=False)
+    datasource = relationship(
+        'DruidDatasource',
+        backref=backref('columns', cascade='all, delete-orphan'),
+        enable_typechecks=False)
     column_name = Column(String(255))
     is_active = Column(Boolean, default=True)
     type = Column(String(32))
@@ -2006,7 +2019,10 @@ class Query(Model):
 
     database = relationship(
         'Database', foreign_keys=[database_id], backref='queries')
-    user = relationship('User', backref='queries', foreign_keys=[user_id])
+    user = relationship(
+        'User',
+        backref=backref('queries', cascade='all, delete-orphan'),
+        foreign_keys=[user_id])
 
     __table_args__ = (
         sqla.Index('ti_user_id_changed_on', user_id, changed_on),