Oracle 1z0-591 Oracle Business Intelligence Foundation Suite 11g Essentials Exam Practice Test

Modeling Time Series Function in OBIEE

Modeling Time Series Data

Time series functions provide the ability to compare business performance with previous time periods, allowing you to analyze data that spans multiple time periods. For example, time series functions enable comparisons between current sales and sales a year ago, a month ago, and so on.

Because SQL does not provide a direct way to make time comparisons, you must model time series data in the Oracle BI repository. First, set up time dimensions based on the period table in your data warehouse. Then, you can define measures that take advantage of this time dimension to use the AGO, TODATE, and PERIODROLLING functions.

The relationship is defined at the model and mapping layer.

Note:

At the highest level, an OBIEE Metadata Repository includes three layers of information:

1.

First, a Physical layer is defined. The metadata layer identifies the source data.

2.Second, a Business Model and Mapping layer is defined. This metadata layer organizes the physical layer into logical categories and records the appropriate metadata for access to the source data.

3.Finally, the Presentation layer is defined. This metadata layer exposes the business model entities for end-user access.

If you want to create a dynamic time-series reference such as the value of a measure as at this time last year, or over the past three months, or year-to-date, you can use one of the OBIEE time-series functions (AGO, PERIODROLLING, TODATE) to provide an offset value for a measure.

Figure:

Note: OBIEE 11g offered a bunch of improvements that were particularly aimed at Essbase, and other OLAP server, customers; the new hierarchical columns feature brought proper OLAP analysis to OBIEE, and coupled with OLAP-oriented features such as hierarchical prompts and selection steps, made OBIEE 11g a much more conducive environment for Essbase users.

There’s much better support for Essbase-native features such as value-based hierarchies, alternate hierarchies, multiple alias tables, UDAs and other Essbase artifacts, and the value-based hierarchy feature in particular is very welcome as it can avoid the need to completely re-import your Essbase database if your outline gains additional hierarchy levels.

So coupled with the new and improved visualization capabilities in OBIEE 11g, including maps, scorecards, improved dashboard controls, the whole new UI, improved BI Publisher and so on, there’s a lot to recommend OBIEE 11g to users of the “legacy” Hyperion tools looking for a bit of a refresh of their BI environment.

Aggregate Persistence Wizard automates the creation and initial population of aggregates, persists them in a back-end database and configures the BI Server metadata layer so that they’re used when appropriate.

An action link is a link to an action that you have embedded in an analysis, dashboard page, scorecard objective, scorecard initiative, or KPI that, when clicked, runs an associated action.

All metadata for cubes and dimensions is stored in the Oracle database and revealed in the data dictionary views, so that you can query the entire business model in SQL.

This warning indicates that the given column is only mapped to logical table sources that are disabled. The warning brings this issue to the repository developer's attention in case the default behavior is not desired.

Identity Store: It is directory server to perform the authentication. It contains user name , password and groups membership information .When a user name and password combination is entered at log in, the authentication provider searches the identity store to verify the credentials provided.

See figure below.

Oracle BI Cluster Server Components

* Oracle Business Intelligence Cluster Controller: The Cluster Controller determines which BI Server works in the cluster. It monitors the operation of servers in the cluster. The Cluster Controller is deployed in active-passive mode.

* Clustered BI Servers: The BI Cluster Server feature supports up to 16 BI Servers in a network domain to act as a single server. BI Servers in the cluster share requests from multiple Oracle BI clients.

* Master BI Server: A clustered Oracle Business Intelligence Server is designated as the Master BI Server. The Oracle Business Intelligence Administration Tool connects to the master BI Server for online repository changes.

* Cluster Manager: The Cluster Manager is available in the Administration Tool when a repository is opened in online mode. The Cluster Manager enables Oracle BI Server clustered instances.

You can specify a Driving table parameter in a complex join.

Driving tables are for use in optimizing the manner in which the Oracle BI Server processes cross-database joins when one table is very small and the other table is very large.

The BI Server will query the driving table (the small one) and will get a list of values. The BI Server will then generate a second SQL using a parameterized IN list with the values from the first query.

Specifying driving tables leads to query optimization only when the number of rows being selected from the driving table is much smaller than the number of rows in the table to which it is being joined.

You can control the way that the interface for Oracle BI EE is displayed to users by creating skins and styles.

While skins and styles are typically used to customize the look and feel of analyses and dashboards by providing logos, color schemes, fonts, table borders, and other elements, they can also be used to control the position and justification of various elements by including specialized style tags in the relevant style sheet (.css) file.

You can check the directory skin location with a right click on a OBIEE dashboard page, select show source code and search “custom.css”.

Denormalized data in the transactional system could be divided into different tables to increase performance.

B: The problem with caching of any kind is how to deal with stale data. How you decide to deal with this depends on how time critical your business intelligence queries happen to be. OBIEE provides a wide variety of mechanisms for dealing with stale data. The cache can be purged automatically at intervals. Caching can be enabled selectively for individual physical tables, so that data in a frequently updated table is never cached. OBIEE provides a set of ODBC procedures that can be called when ETL processes complete to programmatically purge designated tables. But, by far the best way to selectively purge the cache is to use an event polling table. This table is populated by the client database whenever changes are made to any table (by an ETL process for a data warehouse or by a table-based trigger for an OLTP database). At specified intervals the BI Server polls this event polling table and deletes from its cache any query results that are dependent on the changed data.

You do not use ODBC DSN to compare repositories.

Note: When an ODBC based application connects to a database, it connects to a logical name, the Data Source Name (DSN), which identifies the datasource to which it wants to connect.

Some external repository of configuration information holds the various DSN values that are available, together with the necessary configuration and control information needed by the ODBC driver to establish a connection and manage usage of the data source.

The DSN (data source name) is a data structure that contains the information about a specific data source (database, …), typically used by an ODBC driver to be able to connect to it.

The DSN contains information about the data source such as:

the name,

the directory,

and the driver.

On Windows, the DSN also specifies the ODBC driver to be used to access the database.

All others are names for level-based measure but Sales is a base measure.