Deriving custom semantic types

You can derive custom semantic types from semantic types that are stored in the standard library to provide more accurate classification of the data that you assign them to.

Before you begin

Search carefully for an available semantic type before you derive your own custom one. Defining a custom semantic type when the library already contains an appropriate semantic type can cause problems with information retrieval and matching.

About this task

Typically, you might derive a custom semantic type when you define an entity type, link type, or attribute class. You can also derive custom semantic types wherever you can assign a semantic type. For example, you can assign a semantic type to a single entity on the chart surface.

When you derive a custom semantic type, it is important to choose the correct parent semantic type, so that Analyst's Notebook interprets the data correctly. Some semantic types are used by Analyst's Notebook for entity matching. The Find Matching Entities feature uses semantic types that are assigned to entities, links, and attributes as part of its smart matching behavior.

Procedure

To derive a custom semantic type:
  1. In any window where you can select a semantic type, such as when you are defining an item type or attribute class, click the Semantic Type browse button. The Select Semantic Type window opens.
    The Semantic Types pane shows the entity, link, or property semantic type hierarchy.
  2. Expand the hierarchy to find the semantic type from which you want to derive your custom semantic type. Right-click the semantic type, then click New.
    Note:
    You cannot derive a custom semantic type from the Abstract Binary property semantic type. This special category of semantic type is reserved for internal use.
  3. Enter a name for the custom semantic type in the Name box.
    The name must be unique within the semantic type hierarchy.
  4. To improve your ability to search for this semantic type, add synonyms in the Synonyms box.
    For example, synonyms for the semantic type Mail in the i2 Semantic Type Library are Letter, Parcel, and Post.
    Use commas to separate the synonyms.
  5. Describe what this semantic type is used for in the Description box.
    You can also include hyperlinks to further information.
  6. Click OK to save the custom semantic type and assign it to the entity type, link type, or attribute class.

Results

Custom semantic types are saved with your chart. Any custom semantic types that are not assigned to chart items, chart item types, and attribute classes are lost when you save and close your chart. To reuse custom semantic types in a new chart:
  • Create a template based on your current chart and base your new chart on this template.
  • Save your current set of custom semantic types in a new library file (.mtc file) which other Analyst's Notebook users can load and use.