Queries

A query is, in simplest terms, a request for specific information from the database. It allows you to determine what information you want to see and the order in which you want to see it. Queries are used to display most objects on a list window. They allow you to decide what columns of data will be displayed on the list window, and how it will be sorted. Queries also have the ability to provide selection criteria. Selection criteria can be used to limit the records that are displayed in a list window. Queries can also be used to improve performance by limiting the number of documents and columns that appear on a list window.

The query function in Data Interchange Services client gives you extensive control over the information that appears in any list window. Queries control both the number of documents that are listed and the number of fields that displayed. They are particularly useful after you have been using Data Interchange Services client for a while and the number of items on your list window is large.

A query is executed each time any list window is opened in Data Interchange Services client. You see the results of that query displayed on the list window of each tab. For example, when you open the Data Transformation Maps list window in the Mapping Functional Area, the default "All" query is often run. This query locates all data transformation maps and displays the results on the list window. The list window opened with this query lists all data transformation maps and sorts them by name.

You can change which query is executed to display the result on the list window. It can be changed to any available query that exists on the database. The available queries can include default queries provided by Data Interchange Services client and other queries that you or other persons have created. Use the Properties button on the list window toolbar to change which query is executed on an open list window.

A query can be created that is "public", "protected", or "private." This function is only useful in installations where the Data Interchange Services client Configuration database is shared by several users. A public query is available to all users of the shared Configuration database. Any user can access the query and can alter or even delete the query. Protected queries are available to all users of the shared Configuration database; however, only the creator of the query can alter or delete it. Only the user that created the query can access private queries.

Copyright IBM Corp. 2003, 2005