python - 如何“重置”在使用来自 Flask 应用程序的数据库的 Python 脚本中运行的 db.session？

Question

我有以下代码：

from flask_migrate import upgrade

app = create_app()

with app.app_context():
    # Merge branch into master and then upgrade the database
    os.system("git pull origin BRANCH-B")
    
    # Upgrade the database (equivalent to flask db upgrade)
    # Assume here that a new column was added called: new_column
    upgrade()
    
    # Adding a row to the database using a Model object and complying with the
    # NEW database rows and format (after upgrade)
    model = Model(id=1, new_column = "test")
    
    # Above line gives an error

sqlalchemy.exc.OperationalError：（pymysql.err.OperationalError）（1054，“'字段列表'中的未知列'new_column'”）

这意味着 db.session 在执行升级操作后不会“刷新”数据库。知道怎么做吗？

谢谢，

问候。

标签： pythonflasksqlalchemyflask-sqlalchemy

Answer 1

我最终使用 mysql 连接器（package mysql-connector-pythonin pip）连接到 mysql，然后连接到数据库并插入我想使用 mysqlINSERT语句手动插入的记录。

作为参考，这里是语法：

...
import mysql.connector

def insert_new_records():
    app = create_app()
    with app.app_context():
        cnx = mysql.connector.connect(
            user=app.config['SQL_USERNAME'], 
            password=app.config['SQL_PASSWORD'], 
            port=app.config['SQL_PORT'],
            database=app.config['DATABASE']
        )
        cursor = cnx.cursor()

        insert_stmt = (
          "INSERT INTO table (id, new_column) "
          "VALUES (%s, %s)"
        )

        # Insert new rows
        id = 1
        new_column = "test" # Could be any Python datatype
        data = (id, new_column)
        cursor.execute(insert_stmt, data)
        cnx.commit()