在 Cassandra 中查询，从一组 UDT 中检索

Question

作为 UDT 的城市信息。城市代码将为 'work' 或 'home' 或 'templocation'。

CREATE TYPE facetmanager_ps1.city (
    id int,
    citycode text,
    cityname text
);

一个拥有part_time_employees列表的UDT；它有一组城市UDT

CREATE TYPE facetmanager_ps1.part_time_employees (
    firstname text,
    lastname text,
    address_set frozen<set<frozen<city>>>
);

持有雇员information.It的table有一组part_time_employee_set。

CREATE TABLE facetmanager_ps1.employee (
    id int PRIMARY KEY,
    name text,
    part_time_employee_set set<frozen<part_time_employees>>,
    PRIMARY KEY (id)
)


insert into employee (id,name,part_time_employee_set) 
values 
( 1, 'raghu', 
    {
        {
            firstname: 'r1',
            lastname:'r2',
            address_set : {
                {
                    id: 600000,
                    citycode: 'work',
                    cityname: 'chennai'
                },
                {
                    id:600020,
                    citycode: 'home',
                    cityname: 'kanchipuram'
                }
            }
        }
    }
);


update employee set part_time_employee_set
= part_time_employee_set + 
{ { firstname: 'arun', lastname : 'kannan', address_set :
    {
        {
            id: 600000,
            citycode:'work',
            cityname: 'chennai'
        },
        {
            id: 600000,
            citycode:'home',
            cityname: 'chennai'
        }
    }
}} where id=1;

select * 来自 id=1 的员工；它提供了所有 part_time_employee 信息

我的主要问题：

现在我只想要 part_time_employee r1 的员工信息。我想要他的工作地点和家庭地点，即）我想要完整的 address_set 如何获得？

select * from employee where id=1 and part_time_employee_set = { { firstname: 'r1' }};
InvalidRequest: Error from server: code=2200 [Invalid query] message="Collection column 'part_time_employee_set' (set<frozen<part_time_employees>>) cannot be restricted by a '=' relation"

select * from employee where id=1 and part_time_employee_set in { { firstname: 'r1' }};
SyntaxException: line 1:64 no viable alternative at input '{' (...employee where id=1 and [part_time_employee_set] in...)

问题 2：（小问题）

select * from employee;

<<set(2)>>

如何在devcenter中显示展开后的结果？. "Expand ON" 命令在开发中心不作为命令运行但是，如果我复制值被复制到文本编辑器或其他编辑器中。目前这不是我主要关心的问题。

Answer 1

不能使用非主键查询，除非创建索引。

即使您在 part_time_employee_set 集合上创建索引，您也无法使用一块冻结字段 (firstname) 进行查询。 Frozen fields 意味着要紧凑。还有一件事你不能 select 集合中的部分项目。您需要 select 整个系列。

如果您想使用名字进行查询，则必须更改您的数据模型。

CREATE TABLE employee (
    id int,
    firstname text,
    lastname text,
    address_set set<frozen<city>>,
    name text static,
    PRIMARY KEY (id, firstname, lastname)
);

现在您可以 select address_set 名 'r1'

的兼职员工

SELECT * FROM employee_test WHERE id = 1 AND firstname = 'r1';

输出：

 id          | 1
 firstname   | r1
 lastname    | r2
 name        | raghu
 address_set | {{id: 600000, citycode: 'work', cityname: 'chennai'}, {id: 600020, citycode: 'home', cityname: 'kanchipuram'}}

在 Cassandra 中查询，从一组 UDT 中检索

Querying in Cassandra, retrieving from a SET of UDT

cassandra

cassandra-cli

cassandra-2.1