作者: Jason

What is a universe?

A universe is a file that contains the following:
• Connection parameters for one or more database middleware.
• SQL structures called objects that map to actual SQL structures in the database such as columns, tables, and database functions. Objects are grouped into classes. Objects and classes are both visible to Web Intelligence users.
• A schema of the tables and joins used in the database. Objects are built from the database structures that you include in your schema. The schema is only available to Designer users. It is not visible to Web Intelligence and Desktop Intelligence users.

Web Intelligence users connect to a universe, and run queries against a database. They can do data analysis and create reports using the objects in a universe, without seeing, or having to know anything about, the underlying data structures in the database.

What is the role of a universe?

The role of a universe is to provide an easy to use and understand interface for non technical Web Intelligence users to run queries against a database to create reports and perform data analysis.

As the universe designer, you use Designer to create objects that represent database structures, for example columns and database functions, that users need to access and query, to get the information necessary to meet their business requirements. The objects that you create in the universe must be relevant to the end user business environment and vocabulary. Their role is to present a business focussed front end to the SQL structures in the database.

The following diagram shows the role of objects as the mapping layer between a database schema and the Query work area in Web Intelligence, that users use to create queries to run against database tables.

What does a universe contain?

A universe contains the following structures:
• Classes
• Objects

Classes

A class is a logical grouping of objects within a universe. It represents a
category of objects. The name of a class should indicate the category of the
objects that it contains. A class can be divided hierarchically into subclasses.

Objects

An object is a named component that maps to data or a derivation of data in
the database. The name of an object should be drawn from the business
vocabulary of the targeted user group. For example, objects used in a
universe used by a product manager could be Product, Life Cycle, or Release
Date. A universe used by a financial analyst could contain objects such as
Profit Margin, and Return on Investment.

Types of objects

In Designer, objects are qualified as one of three types: dimension, detail, or
measure.

1. Dimension –> Parameters for analysis. Dimensions typically relate to a
   hierarchy such as geography, product, or time. For example
   Last Name and City_Id
2. Detail –> Provide a description of a dimension, but are not the focus
   for analysis. For example Phone Number
3. Measure –> Convey numeric information which is used to quantify a
   dimension object. For example Sales Revenue

Objects infer SQL structures displayed in a schema

The objects that Web Intelligence users see in a universe infer SQL
structures that you have inserted into a database schema. You, as the
universe designer, create this schema based on the tables and joins that are
required to return the data, needed by users for their analysis and report
creation.
The schema is a part of the universe file, but is only visible and accessible in
Designer.