合并JWL，WZY，TRM代码
Change-Id: Ifb4fcad3c06733e1e005e7d8d9403e3561010fb4
diff --git a/Merge/back_wzy/models/comment.py b/Merge/back_wzy/models/comment.py
new file mode 100644
index 0000000..ce25287
--- /dev/null
+++ b/Merge/back_wzy/models/comment.py
@@ -0,0 +1,24 @@
+# models/comment.py
+from extensions import db
+from datetime import datetime
+
+class Comment(db.Model):
+ __tablename__ = 'comments'
+
+ id = db.Column(db.Integer, primary_key=True)
+ post_id = db.Column(db.Integer, db.ForeignKey('posts.id', ondelete='CASCADE'), nullable=False)
+ user_id = db.Column(db.Integer, db.ForeignKey('users.id', ondelete='CASCADE'), nullable=False)
+ parent_id = db.Column(db.Integer, db.ForeignKey('comments.id', ondelete='CASCADE'))
+ content = db.Column(db.Text, nullable=False)
+ status = db.Column(db.Enum('active', 'deleted'), default='active', nullable=False)
+ created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)
+ updated_at = db.Column(db.DateTime, default=datetime.utcnow,
+ onupdate=datetime.utcnow, nullable=False)
+
+ # self-referential replies
+ replies = db.relationship(
+ 'Comment',
+ backref=db.backref('parent', remote_side=[id]),
+ lazy='dynamic',
+ cascade='all, delete-orphan'
+ )