Association de 3 tables fonctionnel avec le code SQL Expression Language (get_roles, ...)

relationship/association_object_ternary.py

@@ -8,6 +8,9 @@ from sqlalchemy import Column, ForeignKey, Integer, Text, DateTime
 from sqlalchemy.orm import declarative_base, relationship
 from sqlalchemy.orm.session import Session
 
+# Mix ORM with Core SQL Expression language ???
+# https://docs.sqlalchemy.org/en/14/core/tutorial.html
+from sqlalchemy import select
 
 Base = declarative_base()
 
@@ -25,9 +28,15 @@ class UserOrgRole(Base):
     )
 
     # I do not know what the relationship could back populate, org or role ???
-    user = relationship("User")
-    org = relationship("Org")
-    role = relationship("Role")
+    user = relationship("User", back_populates="orgsroles")
+    org = relationship("Org", back_populates="usersroles")
+    role = relationship("Role", back_populates="usersorgs")
+
+    def __repr__(self):
+        return (
+            f"<UserOrgRole (user_id={self.user_id}, org_id={self.org_id}, "
+            f"role_id={self.role_id})>"
+        )
 
 
 class User(Base):
@@ -38,12 +47,43 @@ class User(Base):
     fullname = Column(Text, nullable=False)
     account_type = Column(Text, nullable=False)
 
+    orgsroles = relationship("UserOrgRole", back_populates="user")
+
     def __repr__(self):
         return (
             f"<User (username={self.username}, fullname={self.fullname}, "
             f"account_type={self.account_type})>"
         )
 
+    def get_roles(self, session):
+        stmt = (
+            select(Role)
+            .select_from(UserOrgRole)
+            .join(Role, UserOrgRole.role_id == Role.id)
+            .where(UserOrgRole.user_id == self.id)
+        )
+        print(stmt)
+        results = session.execute(stmt)
+        print(results)
+        # <sqlalchemy.engine.result.ChunkedIteratorResult object at 0x7f35d3bdd040>
+        # https://docs.sqlalchemy.org/en/14/core/connections.html#sqlalchemy.engine.ChunkedIteratorResult
+        for row in results:
+            # Pourquoi row semble être un tuple qui contient l'objet ?
+            # type(row)
+            # <class 'sqlalchemy.engine.row.Row'>
+            # type(row[0])
+            # <class '__main__.Role'>
+            print(row[0].name)
+
+    def get_uor(self, session):
+        # https://docs.sqlalchemy.org/en/14/orm/session_api.html?highlight=session%20execute#sqlalchemy.orm.Session.execute
+        stmt = select(UserOrgRole).where(UserOrgRole.user_id == self.id)
+        print(stmt)
+        results = session.execute(stmt)
+        for row in results:
+            uor = row[0]
+            print(uor)
+
 
 class Org(Base):
     __tablename__ = "org"
@@ -53,6 +93,8 @@ class Org(Base):
     slug = Column(Text, index=True, nullable=False)
     created_at = Column(DateTime)
 
+    usersroles = relationship("UserOrgRole", back_populates="org")
+
     def __repr__(self):
         return (
             f"<Org (name={self.name}, slug={self.slug}, "
@@ -66,6 +108,8 @@ class Role(Base):
     id = Column(Integer, primary_key=True)
     name = Column(Text, index=True, nullable=False)
 
+    usersorgs = relationship("UserOrgRole", back_populates="role")
+
     def __repr__(self):
         return f"<Role (name={self.name})>"
 
@@ -85,17 +129,71 @@ if __name__ == "__main__":
             fullname="Jack London",
             account_type="member",
         )
+
+        u2 = User(
+            username="jdoe",
+            fullname="John Doe",
+            account_type="member",
+        )
+
         o1 = Org(name="o1", slug="o1", created_at=datetime.utcnow())
+        o2 = Org(name="o2", slug="o2", created_at=datetime.utcnow())
+
         owner = Role(name="owner")
+        reader = Role(name="reader")
 
         uor1 = UserOrgRole()
         uor1.user = u1
         uor1.org = o1
         uor1.role = owner
 
+        uor2 = UserOrgRole()
+        uor2.user = u2
+        uor2.org = o1
+        uor2.role = reader
+
+        uor3 = UserOrgRole()
+        uor3.user = u2
+        uor3.org = o2
+        uor3.role = owner
+
         with session.begin():
             session.add(u1)
+            session.add(u2)
             session.add(o1)
+            session.add(o2)
             session.add(owner)
+            session.add(reader)
 
             session.add(uor1)
+            session.add(uor2)
+            session.add(uor3)
+
+        # u1.get_uor(session)
+        u1.get_roles(session)
+
+        print(u1)
+        print(u1.orgsroles[0].org)
+        print(u1.orgsroles[0].role)
+
+        print(u2)
+        print(u2.orgsroles[0].org)
+        print(u2.orgsroles[0].role)
+
+        print(o1)
+        print(owner)
+
+    """
+    # Mix ORM with Core SQL Expression language ???
+    user = Base.metadata.tables["user"]
+
+    with engine.connect() as conn:
+        stmt = select(user)
+        for row in conn.execute(stmt):
+            print(row)
+    """
+
+    # Y a-t-il des pistes dans les ORM examples ?
+    # https://docs.sqlalchemy.org/en/14/_modules/examples/join_conditions/threeway.html
+
+    # https://dba.stackexchange.com/questions/150865/how-to-model-a-three-way-association-that-involves-product-category-and-label