Setting up Semantic Types

A semantic type is a category of data that defines how iBase interprets that data. For example, the Person entity semantic type could be applied to entity types such as Male, Victim and Witness. The semantic type allows iBase to understand that each of those entity types are a different way of depicting people in the real world.

All i2 products at your site should use the same Semantic Type Library. To achieve this, assign semantic types to the database schema, and define new ones, in one database only and then distribute them to any other related databases in your organization.

To make use of semantic types, you can assign a semantic type to each relevant entity type, link type, field, standard field, and icon. You do not need to assign a semantic type to everything in your database schema.

Semantic types can then be saved to a file for distribution to others in your organization. Semantic types are also saved in any templates that you create from the database.

How to use semantic types in iBase

Although the Semantic Type dialog is displayed in various locations in iBase Designer, it is only displayed in iBase when a user runs a query that includes semantic types, to allow the selection of entity, link or semantic property types to search.

At this release, users can use semantic types within iBase itself for running queries with semantic conditions. Semantic types are also used when iBase data is charted on Analyst's Notebook charts.

Note: Certain entity types can have Smart Matching behavior in Analyst's Notebook if they have a field that is assigned an identifying property semantic type.

About the Semantic Type library

We provide the i2® Semantic Type Library, which contains semantic types that you assign to data in your data sources. These semantic types identify the meaning of the data they represent, and are used by applications such as Analyst's Notebook to properly interpret and align the data from different data sources.

The library includes three different kinds of semantic type definition:

  • Entity semantic types (for entity types and icons)

  • Link semantic types

  • Property semantic types (for entity and link type fields, including standard fields)

You must decide which kinds of semantic type best represents your data.

Each semantic type consists of the following elements:

  • Name

  • Data type, such as text or number

  • Optional synonyms--- alternative names that are used when searching for suitable semantic types

  • Description that provides guidance on how the type should be used

  • Additional notes

Depending on its location in the hierarchy of semantic types, the function of a semantic type will be general or specific. For example, Motor Vehicle is a specialized type of Transport, and Bus is a specialized type of Motor Vehicle. In the event that Bus is not specific enough, you could create a custom semantic type. However, you should not add any custom types without the agreement of others at your site and, once you have added them, you must share the updated Semantic Type Library with all users of i2 products at your site. For details, see Maintaining the semantic type library.

Assigning semantic types in iBase Designer

There are two ways of assigning semantic types in iBase. You can:

Restrictions on how you assign semantic types

There are a few restrictions on how you assign semantic types:

Entities and icons

You can use any entity semantic type that is suitable for the data. Assigning Semantic Types to your data for details.

Links

You can use any link semantic type that is suitable for the data. See Assigning Semantic Types to your data for details.

Fields

You can use any property semantic type. However, consider the underlying data type when making your choice:

Data Type

Possible Semantic Type

Number

Any of the numerical semantic types found by expanding Abstract Number

Text

Any of the text semantic types found by expanding Abstract Text

Yes or No (Boolean)

Any of the flag semantic types found by expanding Abstract Flag

Date and time

Any of the numerical semantic types found by expanding Abstract Date & Time

Binary

Any of the numerical semantic types found by expanding Abstract Binary

When assigning semantic types to fields, you cannot assign the same semantic type to two or more fields in the same entity or link type. See Assigning Semantic Types to your data for details.

Standard fields

You can use any property semantic type as explained above for Fields. When assigning semantic types to standard fields, you cannot assign the same semantic type to two or more standard fields in the same database.

Note: You cannot assign abstract semantic types to database objects--- you can only create custom semantic types from them.