使用WHERE在SQLAlchemy Core中批量更新

Question

我已经设法使用SQLAlchemy中的批量插入,如:

conn.execute(addresses.insert(), [ 
   {'user_id': 1, 'email_address' : 'jack@yahoo.com'},
   {'user_id': 1, 'email_address' : 'jack@msn.com'},
   {'user_id': 2, 'email_address' : 'www@www.org'},
   {'user_id': 2, 'email_address' : 'wendy@aol.com'},
])

我现在需要的是等同于更新的东西.我试过这个:

conn.execute(addresses.insert(), [ 
   {'user_id': 1, 'email_address' : 'jack@yahoo.com', 'id':12},
   {'user_id': 1, 'email_address' : 'jack@msn.com', 'id':13},
   {'user_id': 2, 'email_address' : 'www@www.org', 'id':14},
   {'user_id': 2, 'email_address' : 'wendy@aol.com', 'id':15},
])

期望每行根据'id'字段进行更新,但它不起作用.我假设这是因为我没有指定WHERE子句,但我不知道如何使用字典中包含的数据指定WHERE子句.

有人能帮助我吗？

Answer 1

阅读文档的" 插入,更新和删除"部分.以下代码应该让您入门:

from sqlalchemy.sql.expression import bindparam
stmt = addresses.update().\
    where(addresses.c.id == bindparam('_id')).\
    values({
        'user_id': bindparam('user_id'),
        'email_address': bindparam('email_address'),
    })

conn.execute(stmt, [
    {'user_id': 1, 'email_address' : 'jack@yahoo.com', '_id':1},
    {'user_id': 1, 'email_address' : 'jack@msn.com', '_id':2},
    {'user_id': 2, 'email_address' : 'www@www.org', '_id':3},
    {'user_id': 2, 'email_address' : 'wendy@aol.com', '_id':4},
])

Answer 2

Flask Session具有调用bulk_insert_mappings和的功能bulk_update_mappings.检查这里.

请注意,您必须在映射中提供主键

# List of dictionary including primary key
user_mappings = [{
    'user_id': 1, # This is pk?
    'email_address': 'jack@yahoo.com',
    '_id': 1
}, ...]

session.bulk_update_mappings(User, user_mappings)
session.commit()