如何在集合集合中嵌套CQL地图集合？

发布于 2025-01-18 11:13:22 字数 398 浏览 1 评论 0 原文

我试图拥有一个可以输出类和老师如下的数据：

CLASS A: John
CLASS B: Jane
CLASS C: Stan

这是我的cqlsh：

CREATE TABLE subjects(
    name TEXT,
    class_and_teachers SET<FROZEN MAP<TEXT, TEXT>>,
    );

但是，我遇到了错误

no viable alternative at input 'MAP' (...   name TEXT,  class_and_teachers SET<[FROZEN] MAP...)

吗？

原文

I am trying to have a data that will output class and teachers as below:

CLASS A: John
CLASS B: Jane
CLASS C: Stan

This is my CQLSH:

CREATE TABLE subjects(
    name TEXT,
    class_and_teachers SET<FROZEN MAP<TEXT, TEXT>>,
    );

However, I got the error

no viable alternative at input 'MAP' (...   name TEXT,  class_and_teachers SET<[FROZEN] MAP...)

Is there something wrong?

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dawn曙光 2025-01-25 11:13:22

试试这个例子 - 将 map 放入 frozen 关键字的 <> - SET ;>> 而不是 SET>。这是必需的，因为 frozen 需要参数：

CREATE TABLE subjects(
    name TEXT PRIMARY KEY,
    class_and_teachers SET<FROZEN <MAP<TEXT, TEXT>>>);

 insert into subjects (name,class_and_teachers) values ('A', {{ 'CLASS A': 'John' }});
 insert into subjects (name,class_and_teachers) values ('B', {{ 'CLASS B': 'Jane' }});
 insert into subjects (name,class_and_teachers) values ('C', {{ 'CLASS C': 'Stan' }});

select * from subjects;

 name | class_and_teachers
------+-----------------------
    C | {{'CLASS C': 'Stan'}}
    B | {{'CLASS B': 'Jane'}}
    A | {{'CLASS A': 'John'}}

Try this example - put map into <> of the frozen keyword - SET<FROZEN <MAP<TEXT, TEXT>>> instead of SET<FROZEN MAP<TEXT, TEXT>>. This is required as frozen expects arguments:

CREATE TABLE subjects(
    name TEXT PRIMARY KEY,
    class_and_teachers SET<FROZEN <MAP<TEXT, TEXT>>>);

 insert into subjects (name,class_and_teachers) values ('A', {{ 'CLASS A': 'John' }});
 insert into subjects (name,class_and_teachers) values ('B', {{ 'CLASS B': 'Jane' }});
 insert into subjects (name,class_and_teachers) values ('C', {{ 'CLASS C': 'Stan' }});

select * from subjects;

 name | class_and_teachers
------+-----------------------
    C | {{'CLASS C': 'Stan'}}
    B | {{'CLASS B': 'Jane'}}
    A | {{'CLASS A': 'John'}}

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