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August [Cradle-7.0]

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Creating Nested Tables in Cradle

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:


  1. First we will create a view to show the to items in the nested table. Run a query to display a list of the items in the to set, these are Verification items first in this case, and display as a table (right-click and choose Table style or choose Table from the Style pulldown menu):
    WorkBench interface

    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:

    View details dialog

    Click Save As and save the new view with an appropriate scope, we will call it Verification table in this example:

    Save View
  2. Run a query to display a list of the items in the intermediate set, these are System Requirement items in our example, and display them as a table:
    Intermediate Query result
  3. Define a new view for the view from the from items to the to items, from System Requirements to Verification items in this case, so right click and choose View Details and modify the current view to include the appropriate attributes:
    View details dialog
  4. Now add a new column to contain the linked items (Verification items in this case) by selecting the column to the left of where the link items are to be shown:
    View details dialog

    Then add the new column by clicking the Add Column button:

    Add Column icon

  5. Select the view cell in this new column:
    View details dialog
  6. In the View Details dialogue, select the Data pulldown list and set the content of this view cell to be Linked Items and the View Details dialogue reconfigures itself:
    View details dialog

    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:

    View details dialog
  7. From the Navigation pulldown list choose a navigation that selects which of the Verification items linked to the system requirements should be shown, and if you are not sure which navigation to use, then choose one of the standard navigations supplied by 3SL, Downwards, Upwards or Bidirectional. Bidirectional is guaranteed to always work, so if you are not sure, then choose this one.
  8. Finally, from the View pulldown list choose the view to be used to show the linked Verification items, the Verification table view that we created earlier, or choose the automatic scope cross referenced view (with Xrefd in its name) that Cradle produces automatically:
    View details dialog
  9. Click Apply to show the view:
    WorkBench View

    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:

    Save View As dialog

    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.

  10. Following the earlier steps to run a requirement query and alter the view we see the following:
    System Req to Ver dialog

    The resulting query shows a nested table from Requirements to linked System Requirements and on to the Verification to include the method and status:

    System Req to Ver View

    If you are happy with the resulting table you may save the view as done previously:

    System Req to Ver View

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