示例

从Kafka源表中读取数据，将 GaussDB (DWS)表作为维表，并将二者生成的宽表信息写入print结果表中，其具体步骤如下：

1. 连接GaussDB(DWS)数据库实例，在GaussDB(DWS)中创建相应的表，作为维表，表名为area_info，SQL语句如下：

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   create table public.area_info( area_id VARCHAR, area_province_name VARCHAR, area_city_name VARCHAR, area_county_name VARCHAR, area_street_name VARCHAR, region_name VARCHAR, PRIMARY KEY(area_id) );

2. 连接GaussDB(DWS)数据库实例，向GaussDB(DWS)维表area_info中插入测试数据，其语句如下：

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   insert into area_info (area_id, area_province_name, area_city_name, area_county_name, area_street_name, region_name) values ('330102', 'a1', 'b1', 'c1', 'd1', 'e1'), ('330106', 'a1', 'b1', 'c2', 'd2', 'e1'), ('330108', 'a1', 'b1', 'c3', 'd3', 'e1'), ('330110', 'a1', 'b1', 'c4', 'd4', 'e1');

3. flink sql创建源表、结果表、维表并执行SQL：

   CREATE TABLE orders (
     order_id string,
     order_channel string,
     order_time string,
     pay_amount double,
     real_pay double,
     pay_time string,
     user_id string,
     user_name string,
     area_id string,
     proctime as Proctime()
   ) WITH (
     'connector' = 'kafka',
     'topic' = 'order_test',
     'properties.bootstrap.servers' = 'KafkaAddress1:KafkaPort,KafkaAddress2:KafkaPort',
     'properties.group.id' = 'dws-order',
     'scan.startup.mode' = 'latest-offset',
     'format' = 'json'
   );
   --创建地址维表
   create table area_info (
       area_id string, 
       area_province_name string, 
       area_city_name string, 
       area_county_name string,
       area_street_name string, 
       region_name string 
   ) WITH (
     'connector' = 'dws',
     'url' = 'jdbc:gaussdb://DwsAddress:DwsPort/DwsDbName',
     'tableName' = 'area_info',
     'username' = 'DwsUserName',
     'password' = 'DwsPassword',
     'lookupCacheMaxRows' = '10000',
     'lookupCacheExpireAfterAccess' = '2h'
   );
   --根据地址维表生成详细的包含地址的订单信息宽表
   create table order_detail(
       order_id string,
       order_channel string,
       order_time string,
       pay_amount double,
       real_pay double,
       pay_time string,
       user_id string,
       user_name string,
       area_id string,
       area_province_name string,
       area_city_name string,
       area_county_name string,
       area_street_name string,
       region_name string
   ) with (
     'connector' = 'print'
    
   );
   insert into order_detail
       select orders.order_id, orders.order_channel, orders.order_time, orders.pay_amount, orders.real_pay, orders.pay_time, orders.user_id, orders.user_name,
              area.area_id, area.area_province_name, area.area_city_name, area.area_county_name,
              area.area_street_name, area.region_name  from orders
       left join area_info for system_time as of orders.proctime as area on orders.area_id = area.area_id;

4. 在Kafka中写入数据：

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   {"order_id":"202103241606060001", "order_channel":"appShop", "order_time":"2021-03-24 16:06:06", "pay_amount":"200.00", "real_pay":"180.00", "pay_time":"2021-03-24 16:10:06", "user_id":"0001", "user_name":"Alice", "area_id":"330106"} {"order_id":"202103251202020001", "order_channel":"miniAppShop", "order_time":"2021-03-25 12:02:02", "pay_amount":"60.00", "real_pay":"60.00", "pay_time":"2021-03-25 12:03:00", "user_id":"0002", "user_name":"Bob", "area_id":"330110"} {"order_id":"202103251505050001", "order_channel":"qqShop", "order_time":"2021-03-25 15:05:05", "pay_amount":"500.00", "real_pay":"400.00", "pay_time":"2021-03-25 15:10:00", "user_id":"0003", "user_name":"Cindy", "area_id":"330108"}

5. 结果参考如下：