work on relations docs

docs_src/relations/docs001.py

@@ -0,0 +1,26 @@
+import orm
+import databases
+import sqlalchemy
+
+database = databases.Database("sqlite:///db.sqlite")
+metadata = sqlalchemy.MetaData()
+
+
+class Album(orm.Model):
+    __tablename__ = "album"
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+
+
+class Track(orm.Model):
+    __tablename__ = "track"
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    album = orm.ForeignKey(Album)
+    title = orm.String(length=100)
+    position = orm.Integer()

docs_src/relations/docs002.py

@@ -0,0 +1,39 @@
+import orm
+import databases
+import sqlalchemy
+
+database = databases.Database("sqlite:///db.sqlite")
+metadata = sqlalchemy.MetaData()
+
+
+class Album(orm.Model):
+    __tablename__ = "album"
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+
+
+class Track(orm.Model):
+    __tablename__ = "track"
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    album = orm.ForeignKey(Album)
+    title = orm.String(length=100)
+    position = orm.Integer()
+
+
+print(Track.__table__.columns['album'].__repr__())
+# Will produce:
+# Column('album', Integer(), ForeignKey('album.id'), table=<track>)
+
+print(Track.__pydantic_model__.__fields__['album'])
+# Will produce:
+# ModelField(
+#   name='album'
+#   type=Optional[Album]
+#   required=False
+#   default=None)

docs_src/relations/docs003.py

@@ -0,0 +1,44 @@
+import databases
+import sqlalchemy
+import orm
+
+database = databases.Database("sqlite:///db.sqlite")
+metadata = sqlalchemy.MetaData()
+
+
+class SchoolClass(orm.Model):
+    __tablename__ = "schoolclasses"
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+
+
+class Category(orm.Model):
+    __tablename__ = "categories"
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+
+
+class Student(orm.Model):
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+    schoolclass = orm.ForeignKey(SchoolClass)
+    category = orm.ForeignKey(Category)
+
+
+class Teacher(orm.Model):
+    __metadata__ = metadata
+    __database__ = database
+
+    id = orm.Integer(primary_key=True)
+    name = orm.String(length=100)
+    schoolclass = orm.ForeignKey(SchoolClass)
+    category = orm.ForeignKey(Category)