Question

我有一个汉字（日文字符）列表，如下所示：

kanji_n3 = ['政', '議', '民', '連']  # But then with 367 Kanji

我有2个表：TableKanji和TableMisc。 TableMisc有一个名为“jlpt”的列，其中一些目前的值为2，但如果汉字位于3，则必须将其更新为值kanji_n3

tableclass.py

import sqlalchemy as sqla
from sqlalchemy.orm import relationship
import sqlalchemy.ext.declarative as sqld
sqla_base = sqld.declarative_base()

class TableKanji(sqla_base):
    __tablename__ = 'Kanji'

    id = sqla.Column(sqla.Integer, primary_key=True)
    character = sqla.Column(sqla.String, nullable=False)

    misc = relationship("TableMisc", back_populates='kanji')

class TableMisc(sqla_base):
    __tablename__ = 'Misc'

    kanji_id = sqla.Column(sqla.Integer, sqla.ForeignKey('Kanji.id'), primary_key=True)
    jlpt = sqla.Column(sqla.Integer)

    kanji = relationship("TableKanji", back_populates="misc")

所以我想出的查询是，kanjiorigin_index.py：

import sqlalchemy as sqla
import sqlalchemy.orm as sqlo
from tableclass import TableKanji, TableMisc

kanji_n3 = ['政', '議', '民', '連']  # But then with 367 Kanji

session.query(TableMisc)\
    .filter(TableMisc.jlpt == 2).filter(TableKanji.character in kanji_n3)\
    .update({TableMisc.jlpt: TableMisc.jlpt + 1}, synchronize_session='fetch')

这会成功运行，但不会更新任何内容。输出：

2016-10-18 04:05:53,908 INFO sqlalchemy.engine.base.Engine SELECT CAST('test plain returns' AS VARCHAR(60)) AS anon_1
2016-10-18 04:05:53,908 INFO sqlalchemy.engine.base.Engine ()
2016-10-18 04:05:53,908 INFO sqlalchemy.engine.base.Engine SELECT CAST('test unicode returns' AS VARCHAR(60)) AS anon_1
2016-10-18 04:05:53,909 INFO sqlalchemy.engine.base.Engine ()
2016-10-18 04:05:53,909 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2016-10-18 04:05:53,909 INFO sqlalchemy.engine.base.Engine SELECT "Misc".kanji_id AS "Misc_kanji_id" 
FROM "Misc" 
WHERE 0 = 1
2016-10-18 04:05:53,909 INFO sqlalchemy.engine.base.Engine ()
2016-10-18 04:05:53,910 INFO sqlalchemy.engine.base.Engine UPDATE "Misc" SET jlpt=("Misc".jlpt + ?) WHERE 0 = 1
2016-10-18 04:05:53,910 INFO sqlalchemy.engine.base.Engine (1,)
2016-10-18 04:05:53,911 INFO sqlalchemy.engine.base.Engine COMMIT

问题

如何更新当前值为2且TableKanji.character位于TableMisc.jlpt的{{1}}？我的kanji_n3声明不是这样的吗？我还尝试添加in kanji_n3，但结果是：

.outerjoin(TableKanji)

Answer 1

似乎您的意图是对已连接的表进行更新。并非所有数据库都支持此功能。

首先，您应该使用in_方法而不是in运算符。

您可以先选择选择，然后更新所有选定的记录，如下所示：

records = session.query(TableMisc).\
    join(TableKanji).\
    filter(TableMisc.jlpt == 2).\
    filter(TableKanji.character.in_(kanji_n3)).\
    all()

for record in records:
    record.jlpt += 1

session.commit()

SQLAlchemy ORM通过检查列表中是否有其他表值来更新值

问题

1 个答案: