Fourth flask-related plugins (flask-session, wtforms, Sqlachemy)

Ways to use SQL in your company:

1. Write Django:orm (Relational object mapping),

2. Write flask and other: There are two ways:

(1) Native SQL: There are two options for using native sql:

A. Pymysql (both Python2 and Python3 support)

B. MYSQLDB (Python2 support only)

(2) Sqlachemy (also an ORM framework, similar to Django's ORM)

The inside of the ORM will call Pymysql or MYSQLDB, so the essence is to Pymysql and MySQLdb

I. Flask SESSION

Fourth flask-related plugins (flask-session, wtforms, Sqlachemy)