IMS/DB Logical Usage

The IMS/DB Logical Usage tab shows the way the segments of the Logical IMS database are used across the programs in the project. Also, for each logical segment, the source physical segment and physical database are presented. Data that is contained in a segment can be grouped in one or more fields. The IMS/DB fields that are used to qualify a call statement are presented as part of the results.

IMS/DB is a hierarchical database (unlike a relational or a network one) and it is made out of segments and their relationships. A segment is similar to a record and it is the basic unit of data for IMS/DB. A segment can have many siblings but it can have only one parent segment. This limits the complexity of the physical database. To overcome this limitation, DL/I allows the database administrator to implement logical relationships in which a segment can have both physical and logical parents. Additional relationships can thus be created within one physical database. Once the logical relationships are implemented, the new structure is known as the Logical Database.

To display the IMS/DB Logical Usage tab, go to Explore Projects tab and select IMS/DB Logical Usage from the Usage in Programs list of analyses to the right of the screen.

The central part of the screen displays the list of attribute filters. By default, all attributes are selected; deselect the ones that you do not want to use. The breadcrumb displays the selected project or projects, the selected attributes together with the filters set for each attribute.

To limit the number of attributes of a certain type that are returned by the filtering operation, use the fields in the Limit column. The default limit is 50; the maximum limit can be set in the corresponding Usage Settings section from the Preferences dialog. For more information, see IMS/DB Logical Usage Settings . The Context column displays the context of the filter operation where relevant. To modify the attributes' order in the list, use the green arrow buttons to the left of the attributes list. When the attributes' order changes, the context of the filtering operation changes. To the right of Attribute filters area, the list of projects is displayed.

Use Save to save the current filter configuration. Use Load to load a previously saved filter configuration.

By default, Enable levels limit is selected and the number of elements that are presented in the Results area is limited by the values set in the Limit column. If you deselect this option, the Limit column from the Attribute filters area disappears and the Results area displays all the results of the analysis. Press Apply to apply the selected filters. When the filtering operation is finished, you can use the black arrow button in the upper left corner of Attribute filters area to hide it and maximize the Results area. To see the IMS/DB Logical Usage parameters in a separate tab, use the arrow button in the upper right corner of IMS/DB Logical Usage tab.

The results of the filtering operation are displayed in the Results area. Use the search field to locate a specific element in the Results tree. Click the adjacent button find only annotated to filter the search results so that only the annotated elements are shown. In the upper right corner of the Results area, the following buttons are available.

Reorder current results, use this button to reorder the results using a different filter configuration. A dialog window presents the list of filters that were used to perform the initial filtering and you can set them in the desired order.

Expand all, click this button to expand the tree.

Collapse all, click this button to fold all the tree branches.

Export Results to CSV File, use this button to export the results together with the used filter configuration.

Place the mouse cursor over a node in the tree to display a tooltip that presents the element category and name. When you select a tree node, the area to the right of the screen is updated to display the graphs, reports, and usage analyses that can be generated for the selected element. Also, the Properties view displays the information available for the selected element.

Physical Database and Physical Segment Name levels are related to Logical Segment level (representing the source database and source segment for logical segment).

Accordingly:

1. Physical Database and Physical Segment will always be under Logical Segment level (even if results level or filters order is changed).

2. If Logical Segment is disabled from filters, those 2 levels will not be displayed in result tree.