Question

如何在sqlalchemy orm中写下表达以下查询？

DELETE FROM ACCESS_STRING_DETAILS WHERE MENU_ID IN(SELECT MENU_ID FROM REDIRECTOR WHERE SERVICE=122)
DELETE FROM TIME_DETAILS WHERE MENU_ID IN(SELECT MENU_ID FROM REDIRECTOR WHERE SERVICE=122)
DELETE FROM REDIRECTOR_INPUT_PARAMS WHERE COMMAND_ID IN(SELECT KEYWORD FROM REDIRECTOR WHERE SERVICE=122)
DELETE FROM REDIRECTOR_COMMANDS WHERE COMMAND_ID IN(SELECT KEYWORD FROM REDIRECTOR WHERE SERVICE=122)
DELETE FROM RANGE_DETAILS WHERE COMMAND_ID IN(SELECT KEYWORD FROM REDIRECTOR WHERE SERVICE=122)
DELETE FROM CLIENT_RSP_DETAILS WHERE KEYWORD IN(SELECT KEYWORD FROM REDIRECTOR WHERE SERVICE=122)
DELETE FROM REDIRECTOR WHERE SERVICE=122

我基本上需要删除表中与MENU_ID和KEYWORD匹配SERVICE表中<{1}}的所有记录

Answer 1

您可以先在SERVICE=122上分别捕捉过滤器;我假设您使用camelcase为所有与表名匹配的表都有模型。

还会存储menu_id和关键字选择以供重复使用：

service_filter = Redirector.service == 122
menu_id_select = session.query(Redirector.menu_id).filter(service_filter)
keyword_select = session.query(Redirector.keyword).filter(service_filter)

现在，您可以对所有删除查询应用这些选择：

(session
    .query(AccessStringDetails)
    .filter(AccessStringDetails.menu_id.in_(menu_id_select))
    .delete(False))
(session
    .query(TimeDetails)
    .filter(TimeDetails.menu_id.in_(menu_id_select))
    .delete(False))
(session
    .query(RedirectorInputParams)
    .filter(RedirectorInputParams.command_id.in_(keyword_select))
    .delete(False))
# etc.

session.query(Redirector).filter(service_filter).delete(False)

这些示例使用带有select语句的Column.in_ method，将后者转换为子选择，以生成如下查询：

DELETE FROM access_string_details WHERE access_string_details.menu_id IN (SELECT redirector.menu_id AS redirector_menu_id 
FROM redirector 
WHERE redirector.service = :service_1)

将:service_1参数设置为122。

Sqlalchemy大规模删除orm创建

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