model

models.py

trans_tags = db.Table('trans_tags',
     db.Column('history_id', db.Integer, db.ForeignKey('trans_history.id')),
     db.Column('tag_id', db.Integer, db.ForeignKey('trans_tag.id')),
)

class TransHistory(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    datetime = db.Column(db.DateTime)
    conductor = db.Column(db.String(20))
    tags = db.relationship('TransTag', secondary = 'trans_tags', backref = 'describes')

    def __init__(self, conductor):
        self.datetime = datetime.now()
        self.conductor = conductor

class TransTag(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    tag_name = db.Column(db.String(20), unique=True)

    def __init__(self, tag_name):
        self.tag_name = tag_name