有没有办法在Cassandra表中选择或过滤UDT列表？

Question

从下面选择回复。如何添加where子句来过滤请求的到达时间之间的航班。

cqlsh:api_itl> select * from generic_response_1;

 trace-id                             | result-index | api | base_price | fare_selection | fare_type | flights                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | sale_price | special_instructions | total_duration
--------------------------------------+--------------+-----+------------+----------------+-----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------+----------------------+----------------
 39485363-cc22-4eff-a502-6d860931c3fb |         IB56 | tbo |       8400 |         Retail |       ADT | [{arrival_date_time: '23-03-2019 14:10', carrier_iata: 'UK', carrier_id: 'UK 816', carrier_name: 'Air Vistara', class_code: 'Q', departure_date_time: '23-03-2019 11:30', flight_duration: 160, field_7_: 'BLR', to: 'DEL', via: ''}, {arrival_date_time: '23-03-2019 22:40', carrier_iata: 'UK', carrier_id: 'UK 835', carrier_name: 'Air Vistara', class_code: 'Q', departure_date_time: '23-03-2019 19:55', flight_duration: 165, field_7_: 'DEL', to: 'MAA', via: ''}] |       9485 |                 null |            670
 39485363-cc22-4eff-a502-6d860931c3fb |          OB4 | tbo |       1000 |         Retail |       ADT |                                                                                                                                                                                                                                            [{arrival_date_time: '08-03-2019 14:55', carrier_iata: '6E', carrier_id: '6E 119', carrier_name: 'Indigo', class_code: 'Q', departure_date_time: '08-03-2019 13:55', flight_duration: 60, field_7_: 'MAA', to: 'BLR', via: ''}] |       1770 |                 null |             60

(2 rows)
cqlsh:api_itl> 

给定输出的数据库结构

CREATE TYPE api_itl.flight (
    arrival_date_time text,
    carrier_iata text,
    carrier_id text,
    carrier_name text,
    class_code text,
    departure_date_time text,
    flight_duration int,
    "from" text,
    "to" text,
    via text
);


CREATE TABLE api_itl.generic_response_1(
    "trace-id" uuid,
    "result-index" text,
    api text,
    base_price float,
    fare_selection text,
    fare_type text,
    flights list<frozen<flight>>,
    sale_price float,
    special_instructions list<text>,
    total_duration int,
    PRIMARY KEY ("trace-id", "result-index")
) 

Answer 1

作为TYPE一部分的数据无法使用CQL进行过滤。相反，请考虑更改数据模型。

首先，将TYPE设为TABLE。

• 考虑将arrival_date_time的数据类型更改为时间戳。
• 另外，添加trace-id，result-index以维护对主表的引用。

CREATE TABLE api_itl.flight (
    arrival_date_time timestamp,
    carrier_iata text,
    carrier_id text,
    carrier_name text,
    class_code text,
    departure_date_time text,
    flight_duration int,
    "from" text,
    "to" text,
    via text,
    "trace-id" uuid,
    "result-index" text,
    PRIMARY KEY ("carrier_id", "arrival_date_time") );

接下来，从原始表中删除list<frozen<flight>>航班。

现在，您可以使用两个查询来获得所需的结果。