数据库开发人员(数据库编程人员)。
数据库编程人员对 SQL JOIN 语句的使用由来已久，通过该语句可以基于相同的属性将两个或更多关系数据库表中的数据组合到一起。
The SQL JOIN statement has long been in the toolkit of database programmers, allowing you to combine the data contained in two or more relational database tables based upon a common attribute.
虽然应用程序编程人员总能一一建立到各个数据源的连接，但更容易的方式还是在应用程序中只使用一个数据库连接。
While it is true that an application programmer can always establish a separate connection to each individual data source, it is much easier to have a single database connection in the application.
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