1. What is Cognos Dynamic Cube? And when to use it?
Dynamic cubes are also referred to as in-memory OLAP cubes in IBM Cognos, that are used for loading data from structured relational data sources under a snowflake or star schema directly. The objective of dynamic cubes is to deliver a quick response to reports and analyze huge volumes of data. This is available in Cognos 10.2 or higher versions. Dynamic cubes are used for addressing the difficulty of high performance and low latency interactive analysis and also for reporting against terabytes of data. Supported databases are DB2, Netezza, Microsoft SQL Server, Oracle, Teradata databases.
2. Explain Dynamic Cube Lifecycle in Cognos?
- Model and Publish (Warehouse and CM)
- Deploy and Manage (Dynamic Cube Server, CM)
- Reporting and Analytics (Dynamic cube, Logs)
- Optimize (Warehouse, CM, Logs).
3. What is Cognos Cube Designer?
Cognos Cube Designer is a modeling tool used for dynamic cubes and dimensional metadata. The object editors, data source explorer, the project explorer tree, and properties panes are the essential elements of the Cognos Cube Designer user interface.
4. Explain Cognos Cube Designer modeling workflow.
- First model your cube definition in Cognos Cube Designer
- Create Dynamic cube
- Deploy your dynamic cube to BI server.
5. How to administrate Dynamic cube?
Administration tasks included while selecting a cube to the QueryService Instance are:
- Start/Stop the Cube
- Monitoring Cube
- Managing the cache
- Scheduling a refresh of the cache.
6. What do you mean by Aggregate Advisor?
Aggregate Advisor is used for the purpose of performance optimization utility. It can analyze dynamic cubes and suggest aggregates when needed to improve cube performance. It specifically generates two types of recommendations.
- In-Memory Recommendations: This aggregate recommendation is implemented by the IBM Cognos Business Intelligence server the next time the cube is started and aggregates are saved in the Content Store.
- In-Database Recommendations: This aggregate recommendation will be implemented automatically to the database and the model.
7. What is a Framework Manager?
For creating a business model of metadata derived from one or more data sources, we use a Framework Manager. In simple words, it’s a windows based tool utilised for publishing business models for Cognos in the form of packages for analytical reporting and analysis purposes.
8. Describe Cognos Access Manager.
Cognos Access Manager establishes a centralized environment for defining, storing, and managing security data to IBM Cognos business information applications.We can set up and manage secure user access to data at one central location itself. With this, we can even handle user sign on information and auto access privileges for the servers and data sources containing necessary data.
9. Explain about Aggregate Cache.
Two types of pre-computed aggregate values are supported by Cognos Dynamic Cubes:
1) Stored in-memory aggregate cache
2) Stored in in-database tables (in-database aggregate)
Aggregate Advisor can suggest a collection of in-memory aggregate. In-memory aggregate does not require the involvement of DBA. Recommendations are stored in Content Manager and take effect next time a cube is started.
10. What is Cognos Report Net?
Cognos Report Net is a web-based business intelligence suite of reporting applications, which is used for creating and running reports. It doesn’t require any additional software to access. Just through a web browser, we can access it. It supports multiple formats such as PDF, Excel, HTML, XML, and CSV.
The components of Report Net are the following:
- Cognos connection
- Framework manager
- Report Studio
- Query Studio
11. What is the difference between Embedded filters and standalone filters?
Both Embedded filters and standalone filters are supported by the Framework Manager. For the purpose of using only one query object or dimension in the filter, we use embedded filters. For reusing the expression, we use standalone filters.
12. What is DTM?
DTM converts data received from reader buff and transits transformation to transformation on a row by row basis. Depending on the requirement, transformation caches are also utilized.
13. What is Cognos Powerhouse? And why is it used?
Cognos Powerhouse supports high-productivity application development that enables you to create data-driven business solutions faster. It supports access for web-based, server/client, and traditional terminal-based. Powerhouse has huge popularity due to its productivity, performance, flexibility, and reliability.
14. Explain Dynamic cube modeling?
In IBM Cognos Dynamic Cubes, we can design and develop dynamic cubes using IBM Cognos Studios for use as data sources. Following tasks needs to be processed to create dynamic cubes:
- Build a Java Database Connectivity (JDBC) data source connection to the relational database in IBM Cognos Administration.
- Import the metadata from Cognos Cube Designer for modeling dynamic cubes.
- Model the dimensional metadata and the dynamic cubes.
- Deploy individual dynamic cubes to the Content Manager as OLAP data sources in IBM Cognos Analytics.
- Publish a package that includes a deployed cube.
- Configure the deployed cube for use as a data source by the Query Service and start the dynamic cube in IBM Cognos Administration.
15. What is warehouse cubing?
Warehouse Cubing services provide a multidimensional view of data collected in a relational database. We can create, import, edit, export, and deploy cube models across relational warehouse schema using the cubing services. Optimization techniques are also supported by cubing services for improving OLAP queries performance.
16. What is a Cognos Reporting tool?
Cognos is an IBM reporting tool which is used for reporting and analysis of various data from different data warehouses.
17. Mention the difference between ‘macros’ and ‘prompt’?
Macro is used to run a set of instructions to execute the report but prompt to provide a way to change the report dynamically.
18. What is a Cube?
The Cube is set to be a multi-dimensional view of dimension and measures and it is used to analyze the data in various forms like Slicing and Dicing.
19. What is called Cognos powerplay?
Cognos powerplay is nothing but a multidimensional on-line analysis of data.
20. What is a Sparse Cube?
A cube in which number of populated cells as a percentage of total cells is too low.
21. What is the use of advanced windows in Turbo Integrator?
Using the Advanced window you can create your own custom scripts.
22. What is the logic of Sparsity in cubes?
On average, the more dimensions a cube has, the greater the degree of sparsity.
23. What is Under Feeding?
Failing to feed cells that contain rules-derived values. This always results in incorrect values and must be avoided at all costs.
24. What are FEEDERS?
It creates a placeholder on cells so that cells will not be skipped during the consolidation.
25. What is FEEDSTRING?
If the rule defines string values for any cells, then FEEDSTRINGS must be inserted as the first line of rule. FEEDSTRINGS declaration ensures that cells containing rules-derived strings are fed. Every calculation statement in a rule should have a corresponding feeder statement.
26. What are simple FEEDERS?
FEEDERS that are applied to calculation within one dimension of one cube.
27. How can we generate cubes in Cognos?
Power Play Transformer contains dimension, measure, model and cube. There are different ways to generate a cube. Steps to be followed:
- Just right click on the cube name and build.
- We can write scripts in UNIX. Using that we can easily generate the cube.
28. What is the use of Cognos decision stream?
Cognos decision stream is set to be a tool which is used for extracting, transforming the data from different data sources to target data source.
