Sqlalchemy 核心，从元组而不是 dict 插入多行 [英] Sqlalchemy core, insert multiple rows from a tuple instead of dict

问题描述

我在 2D 元组中有数据(或者说来自 Numpy 表)，并且需要将其插入到 SQL 表中.将 Sqlalchemy Core 与 SQLite 一起使用，如何有效且简单地将这些数据插入到我的表中?

I have data in a 2D tuple (or say coming from a Numpy table), and need to insert it into an SQL table. Using Sqlalchemy Core with SQLite, how can I efficiently and simply insert this data into my table?

例如来自@eclaird;

Take i.e. from @eclaird;

engine = sa.create_engine('sqlite://', echo=True)
metadata = sa.MetaData()

widgets_table = sa.Table('widgets', metadata,
    sa.Column('id', sa.Integer, primary_key=True),
    sa.Column('bar', sa.String(50)),
    sa.Column('biz', sa.Boolean),
    sa.Column('baz', sa.Integer),
    )
metadata.create_all(engine)

# Assuming this is the data where None holds place for primary key
my_data = [
    (None, "Test", True, 3),
    (None, "Test", True, 3),
    ]

到目前为止，我在 文档中的这一点；所以我有；

So far I'm at this point in the docs; so I have;

engine.execute(widgets_table.insert().values((None, "Test", True, 3)))

哪个有效.但我想一次插入多行，例如

Which works. But I want to insert many rows at once such as

engine.execute(widgets_table.insert().values(((None, "Test", True, 3), (None, "Test", True, 3))))

然后报错；

具有当前数据库版本设置的sqlite"方言不支持就地多行插入.

The 'sqlite' dialect with current database version settings does not support in-place multirow inserts.

也试过了；

insert = widgets_table.insert()

engine.execute(insert, [
                    (None, "Test", True, 3), 
                    (None, "Test", True, 3) 
                    ])

有错误；

AttributeError: 'tuple' 对象没有属性 'keys'

AttributeError: 'tuple' object has no attribute 'keys'

作为最近转换到 SQLalch 的人，我有点迷失在这里.

As a recent convert to SQLalch, I'm a bit lost here.

推荐答案

你遗漏了一些关于你的设置的细节，所以我做了一些事情.插入元组很困难，除非您也插入表的主键，那么为什么不在插入之前根据您的数据创建一个字典?

You're missing some details about your setup so I made something up. Inserting tuples is difficult unless you're inserting the table's primary key too, so why not create a dictionary from your data before insert?

这应该适用于 SQLAlchemy 0.7.6 及更高版本:

This should work with SQLAlchemy 0.7.6 and later:

import sqlalchemy as sa

engine = sa.create_engine('sqlite://', echo=True)
metadata = sa.MetaData()

widgets_table = sa.Table('widgets', metadata,
    sa.Column('id', sa.Integer, primary_key=True),
    sa.Column('foo', sa.String(50)),
    sa.Column('bar', sa.String(50)),
    sa.Column('biz', sa.Boolean),
    sa.Column('baz', sa.Integer),
    )
metadata.create_all(engine)

# Assuming this is your data
values = [
    (None, "Test", True, 3),
    (None, "Test", True, 3),
    ]

with engine.connect() as connection:
    with connection.begin() as transaction:
        try:
            markers = ','.join('?' * len(values[0]))
            ins = 'INSERT INTO {tablename} VALUES ({markers})'
            ins = ins.format(tablename=widgets_table.name, markers=markers)
            connection.execute(ins, values)
        except:
            transaction.rollback()
            raise
        else:
            transaction.commit()

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