Django反向包含/ icontains [英] Django reverse to contains/icontains

问题描述

在此问题已解决问题， code> LIKE 在SQL中操作，例如，如果字段名称是Peter Johnson，我们可以通过这样的查询找到它：

In this question was solved problem for reverse LIKE operation in SQL, for example if field name is "Peter Johnson", we could find it by such query:

select name from user where "Mr. Peter Johnson" like CONCAT('%', name, '%')

有没有办法在Django中做这样的事情 Q object（我正在构建一个大的查询，所以使用raw SQL查询不合理）？

Is there any way to do such thing in Django Q object (I'm building a big query, so using raw SQL query will not be rational)?

推荐答案

不幸的是，Django的ORM没有内置反向LIKE的东西。但是， .extra（）子句可能会比原始查询更容易。

Unfortunately, Django's ORM doesn't have anything built-in for reverse LIKEs. But an .extra() clause may make it a bit easier than a raw query.

我使用了这个：

qs.extra(
    where=['''%s LIKE %s.%s'''],
    params=(
        "string to match",
        FooModel._meta.db_table,
        "bar_field",
    ),
)

上述代码的问题是

1）它不适用于此表单中的sqlite后端（附近的语法错误），它可以在查询中硬编码的表/列名称使用，这并不总是安全的丑陋）;

1) it doesn't work with sqlite backend in this form ("syntax error near .", it does work with table/column names hardcoded in query... which is not always safe and always ugly);

和2）它需要FooModel.bar_field以类似样式％的数据％，所以你可以不匹配任意字符串（可以使用％s LIKE CONCAT（％，％s。％s，％）使它成为DBMS特定的，这不是很好）。

and 2) it requires FooModel.bar_field to have data %in like style% so you can't match arbitrary strings (this can be fixed with a query like %s LIKE CONCAT("%", %s.%s, "%") but it'll make it DBMS-specific, which is not good).

反转LIKE本身应该可以与任何ma jor DBMS，但是我只测试了sqlite和postgres。

Reversed LIKE itself should probably work with any major DBMS, but I tested it only on sqlite and postgres.

也许有人应该泛化我的解决方案，并创建一个可重用的，与DBMS无关的应用程序与特殊的子类查询器/管理器/这个具体任务的Q对象...

Maybe someone should generalize my solution and create a reusable, DBMS-agnostic app with special subclassed queryset/manager/Q-object for this specific task...

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