It is a Last Chapter of OBIEE repository.
There are certain design principles or best practices oracle suggest in designing the OBIEE repository. If you open any standard/sample repository provided by oracle you will understand what exactly I am talking about
Today we will discuss the design principles for Presentation Layer.
Principle 1.Subject Areas
Do not include all presentation layer objects in a single subject area (Presentation Catalog). While it is possible but still not recommended approach.
Principle 2. Development with End Users in Mind
Always develop the presentation layer so that end users are able to understand and use it.
Principle 3. Role Based Subject Area.
It is always good idea to create presentation catalog to suit the needs of individual users or user types. For ex. create a separate presentation catalog for sales managers because they need to see only an overview of an organization.
Principle 4. Presentation Tables
Presentation Tables should consistent across presentation catalog.
- List Dimension tables first.
- Do not mix dimension and fact columns in the same table.
- Apply consistent ordering and naming conventions for tables and columns across catalogs.
- Include the words “measure” or “fact” in the names of the fact presentation tables.
Principle 5. Rule of Seven
Keep presentation catalogs small and easy to understand by limiting the number of tables to seven.
Keep Presentation catalogs small and easy to understand by limiting the number of columns to seven.
Principle 6. Fact Tables
Try to limit the presentation catalogs so that there are no more than a couple of fact presentation tables in each catalog. It is important to avoid situation in which there are multiple join paths existing within one presentation catalog.
Principle 7. Implicit Fact Columns
If you have multiple fact presentation tables, it is always best practice to assign an implicit fact column. Implicit facts come into play when an Answers report contains columns from more than one logical dimension table and no explicit facts.
Principle 8. Canonical Time
Canonical time is a useful way for allowing users to report for a specific period of time across multiple star schema. If you use canonical time ,make sure that the corresponding time presentation table is given a very generic name and that name is consistent across all the presentation catalogs.
It should be the first table in a catalog.
Principle 9. Secondary Time Dimension
This function enables users to build time reports for specific star schema.
Secondary time dimensions can be given their own presentation tables further down the list.We can place all secondary time dimension objects into a single presentation table.
Principle 10. Nesting Presentation Table
Prefix presentation table names with a hyphen to group common objects together into sub folders.
Principle 11. Presentation Object Names & Description
- Use the Alisa tab to keep track of prior names.
- Use the default option that synchronize the presentation column name with the underlying logical column name.
- Use only logical, business -oriented names ( rather than physical object names) in the presentation Layer.