Determine the extension model used by a table.

Before you begin

Role required: admin

About this task

The extension model used by a table is not immediately apparent. While a hierarchy can use a single physical table, the platform displays tables as if each logical table has a unique physical table. For example, when specifying a table for a workflow, you can select Change [change_request] or Incident [incident] even though the parent table, Task [task], uses a single physical table.

Administrators can view the status of flattened table hierarchies, but cannot flatten additional hierarchies. You can configure the form to add the Extension model field if necessary.

Procedure

  1. Navigate to All > System Definition > Tables.
  2. Select a table record.
  3. Review the Extension model field value, which indicates whether the table hierarchy uses multiple unique tables or a single flat table.
    • None: Indicates that the table uses the table per class model. Defines a unique physical table per logical table in a hierarchy. For example, there are separate physical tables for the Asset [alm_asset] table, and its child tables: Hardware [alm_hardware], Consumable [alm_consumable], Facility [alm_facility], and Software License [alm_license].
      Note: If a table has an empty Extension Model field, it is not necessarily a Table Per Class table. If the table extends another table, it actually inherits the model from any parent tables it is extending, and only when none of the parents have a defined extension model is the table’s extension model Table Per Class. This can be seen on many tables that extend the Task table. Incident is a logical table that extends Task and is physically located on Task, but by default has a blank Extension Model value.

      When a table doesn’t extend anything at all, and has a blank Extension Model field, it is a Table Per Class table.

    • Table per hierarchy: Defines a single physical table per logical table hierarchy. For example, there is a single Task [task] table on the MySQL database that contains all the Task, Incident, Problem and Change records. This single physical table is represented as separate logical tables.