modeling many-to-many relationships

ttfrog/db/schema/property.py

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+from ttfrog.db.base import Bases, BaseObject, IterableMixin
+
+from sqlalchemy import Column
+from sqlalchemy import Integer
+from sqlalchemy import String
+from sqlalchemy import Text
+from sqlalchemy import UniqueConstraint
+
+
+__all__ = [
+    'Skill',
+    'Proficiency',
+    'Modifier',
+]
+
+
+class Skill(*Bases):
+    __tablename__ = "skill"
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    name = Column(String, index=True, unique=True)
+    description = Column(Text)
+
+    def __repr__(self):
+        return str(self.name)
+
+
+class Proficiency(*Bases):
+    __tablename__ = "proficiency"
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    name = Column(String, index=True, unique=True)
+
+    def __repr__(self):
+        return str(self.name)
+
+
+class Modifier(BaseObject, IterableMixin):
+    __tablename__ = "modifier"
+    __table_args__ = (
+        UniqueConstraint('source_table_name', 'source_table_id', 'value', 'type', 'target'),
+    )
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    source_table_name = Column(String, index=True, nullable=False)
+    source_table_id = Column(Integer, index=True, nullable=False)
+    value = Column(String, nullable=False)
+    type = Column(String, nullable=False)
+    target = Column(String, nullable=False)