Create a Job and add a tMysqlInput component and a tLogRow component onto the design workspace, and link them using a Row > Main connection.
Select the Contexts view of the Job, and click the [+] button at the bottom of the view to add five rows in the table to define the following variables, all of type String, without defining their values, which will be loaded dynamically at Job execution: host, port, username, password, and database.
Now create another variable named db_connection of type List Of Value.
Click in the Value field of the newly created variable and click the button that appears to open the Configure Values dialog box, and click New... to open the New Value dialog box. Enter the name of one of the database tables holding the database connection details and click OK.
Click New... again to define the other table holding the database connection details. When done, click OK to close the Configure Values dialog box.
Now the variable db_connection has a list of values db_testing and db_production, which are the database tables to load the connection parameters from.
Select the Prompt check box next to the Value field of the db_connection variable to show the Prompt fields and enter the prompt message to be displayed at the execution time.