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中文
  • PowerCenter 10.4.0
  • 所有产品

目录

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  1. 前言
  2. 使用转换
  3. 汇总器转换
  4. 自定义转换
  5. 自定义转换函数
  6. 数据屏蔽转换
  7. 数据屏蔽示例
  8. 表达式转换
  9. 外部过程转换
  10. 筛选器转换
  11. HTTP 转换
  12. Identity Resolution 转换
  13. Java 转换
  14. Java 转换 API 引用
  15. Java 表达式
  16. Java 转换示例
  17. 联接器转换
  18. 查找转换
  19. 查找缓存
  20. 动态查找缓存
  21. 规范器转换
  22. 等级转换
  23. 路由器转换
  24. 序列生成器转换
  25. 排序器转换
  26. 源限定符转换
  27. SQL 转换
  28. 在映射中使用 SQL 转换
  29. 存储过程转换
  30. 事务控制转换
  31. 联合转换
  32. 非结构化数据转换
  33. 更新策略转换
  34. XML 转换

转换指南

转换指南

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默认联接

默认联接

在一个源限定符转换中联接相关表时，集成服务将基于每个表中的相关键联接表。
此默认联接是内部等值联接，在 WHERE 子句中使用以下语法： 
Source1.column_name = Source2.column_name
默认联接中的列必须具有：
  • 主键-外键关系
  • 匹配的数据类型
例如，您可以查看月份的所有订单，包括订单号、订购量和客户名称。ORDERS 表包括每个订单的订单号和订购量，但没有客户名称。要包含客户名称，需要联接 ORDERS 和 CUSTOMERS 表。两个表都包括客户 ID，所以可在一个源限定符转换中联接两个表。
下图显示了使用一个源限定符转换联接两个表的方式：
映射显示了两个源：源限定符转换和表达式转换。这些源和源限定符转换都处于打开状态，以显示端口名称和数据类型。表达式转换处于打开状态，以显示端口名称和表达式。
包括多个表时，集成服务将为映射中使用的所有列生成一个 SELECT 语句。这种情况下，SELECT 语句看起来与以下语句类似： 
SELECT CUSTOMERS.CUSTOMER_ID, CUSTOMERS.COMPANY, CUSTOMERS.FIRST_NAME, CUSTOMERS.LAST_NAME, CUSTOMERS.ADDRESS1, CUSTOMERS.ADDRESS2, CUSTOMERS.CITY, CUSTOMERS.STATE, CUSTOMERS.POSTAL_CODE, CUSTOMERS.PHONE, CUSTOMERS.EMAIL, ORDERS.ORDER_ID, ORDERS.DATE_ENTERED, ORDERS.DATE_PROMISED, ORDERS.DATE_SHIPPED, ORDERS.EMPLOYEE_ID, ORDERS.CUSTOMER_ID, ORDERS.SALES_TAX_RATE, ORDERS.STORE_ID 
FROM CUSTOMERS, ORDERS 
WHERE CUSTOMERS.CUSTOMER_ID=ORDERS.CUSTOMER_ID
WHERE 子句是等值联接，其中包括 ORDERS 和 CUSTOMER 表中的 CUSTOMER_ID。