How to Create Nested Tables
One of the most common needs in any requirements management or systems engineering project is to show how two sets of information relate to each other. This correlation is typically displayed in a table, often described as:
In Cradle, such correlations are shown using a nested table, which show the inter-relationship between two sets of items in a Cradle database. One of these sets of information is typically called the from set and the other (usually shown on the right hand side of the table) is typically called the to set.
Creating a nested table is very simple:
Cradle automatically provides automatic scope views for all item types that are intended to be used when items are shown as cross referenced information. These views all have Xrefd in their names.
In our example, we will create a nested view from Requirements to System Requirements through to Verification items showing the verification method and status. The process will be:
Define a new view for the Verification items when they are shown as linked items with appropriate attributes, so right-click and choose View Details and modify the current view to include appropriate attributes. For this example we have the Identity, Name, Verification Method and Status:
Click Save As and save the new view with an appropriate scope, we will call it Verification table in this example:
Then add the new column by clicking the Add Column button:
We don’t want to show all items linked to the requirements, we only want the Verification items that are linked to the system requirements, so change the Value pulldown list to Cross referenced items of type and set the To Type to be Verification items so that we will only show the Verification items that are linked to each system requirement:
If you are satisfied with the view, then click Save As and save it with an appropriate name and scope, we will use System Requirement to Ver in our example:
This process has created the first layer of a typical nested table. The same process is used to add the Requirements to System Requirements layer in a more complex nested table.
The resulting query shows a nested table from Requirements to linked System Requirements and on to the Verification to include the method and status:
If you are happy with the resulting table you may save the view as done previously: