chore: Add explicit bidirectional performant relationships for SQLA m…

…odel (#22413)

superset/connectors/sqla/models.py

@@ -68,7 +68,14 @@
 )
 from sqlalchemy.engine.base import Connection
 from sqlalchemy.ext.hybrid import hybrid_property
-from sqlalchemy.orm import backref, Query, relationship, RelationshipProperty, Session
+from sqlalchemy.orm import (
+    backref,
+    Mapped,
+    Query,
+    relationship,
+    RelationshipProperty,
+    Session,
+)
 from sqlalchemy.orm.mapper import Mapper
 from sqlalchemy.schema import UniqueConstraint
 from sqlalchemy.sql import column, ColumnElement, literal_column, table
@@ -224,10 +231,10 @@ class TableColumn(Model, BaseColumn, CertificationMixin):
     __tablename__ = "table_columns"
     __table_args__ = (UniqueConstraint("table_id", "column_name"),)
     table_id = Column(Integer, ForeignKey("tables.id"))
-    table: SqlaTable = relationship(
+    table: Mapped["SqlaTable"] = relationship(
         "SqlaTable",
-        backref=backref("columns", cascade="all, delete-orphan"),
-        foreign_keys=[table_id],
+        back_populates="columns",
+        lazy="joined",  # Eager loading for efficient parent referencing with selectin.
     )
     is_dttm = Column(Boolean, default=False)
     expression = Column(MediumText())
@@ -439,10 +446,10 @@ class SqlMetric(Model, BaseMetric, CertificationMixin):
     __tablename__ = "sql_metrics"
     __table_args__ = (UniqueConstraint("table_id", "metric_name"),)
     table_id = Column(Integer, ForeignKey("tables.id"))
-    table = relationship(
+    table: Mapped["SqlaTable"] = relationship(
         "SqlaTable",
-        backref=backref("metrics", cascade="all, delete-orphan"),
-        foreign_keys=[table_id],
+        back_populates="metrics",
+        lazy="joined",  # Eager loading for efficient parent referencing with selectin.
     )
     expression = Column(MediumText(), nullable=False)
     extra = Column(Text)
@@ -535,13 +542,23 @@ def _process_sql_expression(
 
 
 class SqlaTable(Model, BaseDatasource):  # pylint: disable=too-many-public-methods
-    """An ORM object for SqlAlchemy table references"""
+    """An ORM object for SqlAlchemy table references."""
 
     type = "table"
     query_language = "sql"
     is_rls_supported = True
-    columns: List[TableColumn] = []
-    metrics: List[SqlMetric] = []
+    columns: Mapped[List[TableColumn]] = relationship(
+        TableColumn,
+        back_populates="table",
+        cascade="all, delete-orphan",
+        lazy="selectin",  # Only non-eager loading that works with bidirectional joined.
+    )
+    metrics: Mapped[List[SqlMetric]] = relationship(
+        SqlMetric,
+        back_populates="table",
+        cascade="all, delete-orphan",
+        lazy="selectin",  # Only non-eager loading that works with bidirectional joined.
+    )
     metric_class = SqlMetric
     column_class = TableColumn
     owner_class = security_manager.user_model

superset/datasets/api.py

@@ -242,6 +242,9 @@ class DatasetRestApi(BaseSupersetModelRestApi):
         DatasetDuplicateSchema,
     )
 
+    list_outer_default_load = True
+    show_outer_default_load = True
+
     @expose("/", methods=["POST"])
     @protect()
     @safe

superset/examples/birth_names.py

@@ -144,8 +144,8 @@ def _add_table_metrics(datasource: SqlaTable) -> None:
         metrics.append(SqlMetric(metric_name="sum__num", expression=f"SUM({col})"))
 
     for col in columns:
-        if col.column_name == "ds":
-            col.is_dttm = True
+        if col.column_name == "ds":  # type: ignore
+            col.is_dttm = True  # type: ignore
             break
 
     datasource.columns = columns

superset/models/dashboard.py

@@ -423,11 +423,6 @@ def export_dashboards(  # pylint: disable=too-many-locals
                 remote_id=eager_datasource.id,
                 database_name=eager_datasource.database.name,
             )
-            datasource_class = copied_datasource.__class__
-            for field_name in datasource_class.export_children:
-                field_val = getattr(eager_datasource, field_name).copy()
-                # set children without creating ORM relations
-                copied_datasource.__dict__[field_name] = field_val
             eager_datasources.append(copied_datasource)
 
         return json.dumps(

superset/models/helpers.py

@@ -327,7 +327,10 @@ def import_from_dict(
         # Recursively create children
         if recursive:
             for child in cls.export_children:
-                child_class = cls.__mapper__.relationships[child].argument.class_
+                argument = cls.__mapper__.relationships[child].argument
+                child_class = (
+                    argument.class_ if hasattr(argument, "class_") else argument
+                )
                 added = []
                 for c_obj in new_children.get(child, []):
                     added.append(

tests/integration_tests/charts/api_tests.py

@@ -1315,9 +1315,10 @@ def test_import_chart(self):
 
         chart.owners = []
         dataset.owners = []
-        database.owners = []
         db.session.delete(chart)
+        db.session.commit()
         db.session.delete(dataset)
+        db.session.commit()
         db.session.delete(database)
         db.session.commit()
 
@@ -1387,9 +1388,10 @@ def test_import_chart_overwrite(self):
 
         chart.owners = []
         dataset.owners = []
-        database.owners = []
         db.session.delete(chart)
+        db.session.commit()
         db.session.delete(dataset)
+        db.session.commit()
         db.session.delete(database)
         db.session.commit()
 

tests/integration_tests/databases/api_tests.py

@@ -1987,8 +1987,8 @@ def test_import_database(self):
         assert str(dataset.uuid) == dataset_config["uuid"]
 
         dataset.owners = []
-        database.owners = []
         db.session.delete(dataset)
+        db.session.commit()
         db.session.delete(database)
         db.session.commit()
 
@@ -2058,8 +2058,8 @@ def test_import_database_overwrite(self):
         )
         dataset = database.tables[0]
         dataset.owners = []
-        database.owners = []
         db.session.delete(dataset)
+        db.session.commit()
         db.session.delete(database)
         db.session.commit()
 

tests/integration_tests/datasets/api_tests.py

@@ -1988,8 +1988,8 @@ def test_import_dataset(self):
         assert str(dataset.uuid) == dataset_config["uuid"]
 
         dataset.owners = []
-        database.owners = []
         db.session.delete(dataset)
+        db.session.commit()
         db.session.delete(database)
         db.session.commit()
 
@@ -2090,8 +2090,8 @@ def test_import_dataset_overwrite(self):
         dataset = database.tables[0]
 
         dataset.owners = []
-        database.owners = []
         db.session.delete(dataset)
+        db.session.commit()
         db.session.delete(database)
         db.session.commit()