Question

在Python中，使用SQLAlchemy，我想插入或更新一行。我试过这个：

existing = db.session.query(Toner)
for row in data:
    new = Toner(row[0], row[1], row[2])

它不起作用。如何在new表中插入或更新Toner？我怀疑它已经完成了合并，但我无法理解如何做到这一点。

Answer 1

假设某些列名......

插入一个

newToner = Toner(toner_id = 1,
                    toner_color = 'blue',
                    toner_hex = '#0F85FF')

dbsession.add(newToner)   
dbsession.flush()

插入多个

newToner1 = Toner(toner_id = 1,
                    toner_color = 'blue',
                    toner_hex = '#0F85FF')

newToner2 = Toner(toner_id = 2,
                    toner_color = 'red',
                    toner_hex = '#F01731')

dbsession.add_all([newToner1, newToner2])   
dbsession.flush()

<强>更新

q = dbsession.query(Toner)
q = q.filter(Toner.toner_id==1)
record = q.one()
record.toner_color = 'Azure Radiance'

dbsession.flush()

或使用MERGE

使用花哨的单行内容

record = dbsession.merge(Toner( **kwargs))

Answer 2

我尝试了很多方法，最后尝试了这一点：

def db_persist(func):
    def persist(*args, **kwargs):
        func(*args, **kwargs)
        try:
            session.commit()
            logger.info("success calling db func: " + func.__name__)
            return True
        except SQLAlchemyError as e:
            logger.error(e.args)
            session.rollback()
            return False

    return persist

和：

@db_persist
def insert_or_update(table_object):
    return session.merge(table_object)

Answer 3

INSERT .. ON DUPLICATE KEY UPDATE ..

SQL：

INSERT INTO the_table (id, col1) VALUES (%s, %s) ON DUPLICATE KEY UPDATE col1 = %s

在py代码中：（用sqlalchemy 1.4.x测试，用mysql）

def test_insert_or_update():
    insert_stmt = insert(the_table).values(
        id = 'xxx',
        col1 = 'insert value',
    )
    on_duplicate_key_stmt = insert_stmt.on_duplicate_key_update(
        # col1 = insert_stmt.inserted.data,
        col1 = 'update value',
        col2 = 'mark'
    )
    print(on_duplicate_key_stmt)
    session.execute(on_duplicate_key_stmt)
    session.commit()

SQLAlchemy插入或更新示例

3 个答案:

INSERT .. ON DUPLICATE KEY UPDATE ..