BIEE Introduction (iii) business model layer

As its name implies (business Model and Mapping layer), the service logic layer needs to reorganize the physical layer's data source into a business user's perspective to re-organize the various data sources of the physical layer (so-called Mapping), and in the business logic layer, we will You need to really build a star model in the Data Warehouse, including:

· Fact table

· Dimension table

· Dimension table hierarchy (Hierarchy)

· Fact table metrics (measure) provide a model for the presentation layer to use, so at the business logic level, users need both technical knowledge (data Warehouse star model) and a business perspective (to build a star model that is meaningful to the business). Let's take a look at a comparison between the business model layer and the physical layer it corresponds to: Form top form bottom form top form bottom form top form Bottom

A key definition of the business logic layer at the bottom of the form's top form is: Captures How the users think about the their business using their own vocabulary it is important to note that although the service model layer is also derived from The physical layer's tables and columns, but the business model layer is more focused on the business perspective of all the data. The word mapping means that the user needs to match the data of the business model layer and the physical layer, a logical table from the business logic layer, whose data source can be composed of multiple data sources of the physical layer, and similarly, a column of data for a business model layer, It can also be matched into multiple columns of data from different data sources in the physical layer: for example, suppose we have three different subsystems in the physical layer (north, south, east), if we want to define a sum of sales in the country at the business model level, It is necessary to add the sales of three subsystems to the business model layer to form a national analysis model. This is a very flexible place in the BIEE architecture design. Of course, if we have organized a simple star model data (using physical layer modeling) in the physical layer, we can simply drag it from the physical layer to the business logic layer to form a star model prototype of a usable business logic layer (the star model of the business model layer automatically uses the modeling of the physical layer), Then simply drag the business model into the presentation layer and we can make the simplest data model for querying: Yes, in the simplest model everything is simple, and we can even create a model that can be put into use without building the hierarchical relationship of the dimension table. Only when there is no hierarchical relationship of the dimension table, we can only do some general report, but the result of the report does not go down (a typical operation of business Intelligence report)! One of the most commonly used words in the business model layer is logical, if we say that we are using the table in the physical layer, the table's primary key foreign key, the table column concept, then we have in the business model layer in the physical layer of the noun before the word plus logical, such as:

· Logical Table

· Logical Column

· Logical Primary Key

· Logical Join

。。。 Wait a minute! The real meaning of these words is that the business model layer, our so-called table, column and other concepts can be defined (and the concept of the physical layer is not a one-to-many relationship), such as the business model layer of a table composed of multiple physical layers of tables, etc. This definition and modification of the business model layer does not affect the various definitions of the physical layer so we can even come up with different data in some of the existing business systems, define the required analytic model at the physical layer or the business model layer, but at the same time this definition does not affect any data from the source system at all.

BIEE Introduction (iii) business model layer