Cognos Interview Questions & Answers

What is a Data Warehouse?

A Data Warehouse is a collection of data marts representing historical data from different operation data sources (OLTP). The data from these OLTP are structured and optimized for querying and analysis in a Data Warehouse.

Define Cognos Report Net?

Cognos Report Net is the web-based, dynamic, business intelligence reporting solution from Cognos.

What is Cognos Connection?

It is a Web portal for Cognos 8 and a component which interracts with the Content Store. It is a frontend to publish, find, manage, organize, and view organization’s business intelligence data.

What is Drill Through?

Drill-through reporting allows you to link from one report to another. You can drill through in a number of ways.  A Drill Through id developed with two reports.

1. Parent Report

2. Child Report.

What is difference between content store and content manager?

A content store is a data base which stores the meta data of the reports.

But where as a content manager is a service which is available in dispatcher. which it manages the security.

What is OLAP?

OLAP stands for On Line Analytical Processing, a series of protocols used mainly for business reporting.

What are components of report studio?

Insertable Objects pane > Properties pane > Explorer bar >Report Viewer

Learn Cognos by Tekslate - Fastest growing sector in the industry. 

Explore  Cognos Training Online and course is aligned with industry needs & developed by industry veterans.

Tekslate will turn you into Cognos Expert.

Explain Difference between PowerPlay transformer and power play reports?

Powerplay transformer' is an ‘MOLAP’ tool using which one can create multi dimensional structure called “CUBE”.

Powerplay for reports is used to generate report from the cube.Only one report can be generated from one cube.If u want ‘n’ reports u must create ‘n’ cubes.

What is cube size?

2.0 GBIt depends on ur project requirements.

What is meant by Junk Dimension?

The Junk Dimension also called as garbage dimension.

A junk dimension is a convenient grouping of typically low-cardinality flags and indicators.

What is Cardinality?

Relationships exist between two query subjects. The cardinality of a relationship is the number of related rows for each of the two query subjects. The rows are related by the expression of the relationship; this expression usually refers to the primary and foreign keys of the underlying tables.

How to join multiple db in catalog?

Mutiple database could not be connected in a single catalog. So that we use hotfile for thispurpose.

How to generate cubes in cognos?

Power Play Transformer contain dimension,measure,model and cube. we can generate cube different way. > Just right click on cube name and build.

we can write script in unix. using that we can generate cube.

What is snapshot?

A Snapshot is the copy of data, when we create a snapshot it copies the exact data that'srelated to the at perticular report, we use snapshot when ever we want to compare reports.(Example :we want to compare this months report with previous months).

What is metric store database?

A metric store database is a special case of a query database. A metric storedatabase is used to store the information associated with metrics that appear inscorecards, including targets performance metrics , thresholds , embership in sorecards links to related reports.

What is difference between view and materialized view?

Views contains query whenever execute views it has read from base table Where as M views loading or replicated takes place only once which gives you better query performance.

What is difference between data mart and data warehouse?

A data mart designed for a particular line of business, such as sales, marketing, or finance.Where as data warehouse is enterprise-wide/organizational.

The data flow of data warehouse depending on the approach.

What is DTM?

DTM transform data received from reader buffer and its moves transformation to transformation on row by row basis and it uses transformation caches when necessary.

What are the different uses of a repository manager?

Repository manager used to create repository which contains metadata the informatica uses to transform data from source to target. And also it use to create informatica user’s and folders and copy, backup and restore the repository.

Explain Informatica Architecture?

Informatica consist of client and server. Client tools such as Repository manager, Designer, Server manager. Repository data base contains metadata it read by informatica server used read data from source, transforming and loading into target.

How do you call a store procedure within a transformation?

In the expression transformation create new out port in the expression write :sp.stored procedure name(arguments).

What is difference between Informatica power mart and power center?

Using power center we can create global repository

Power mart used to create local repository

Global repository configure multiple server to balance session load

Local repository configure only single server

What are the batches and it’s details?

Sequential(Run the sessions one by one)

Concurrent (Run the sessions simultaneously)

What is main difference mapplets and mapping?

Reuse the transformation in several mappings, where as mapping not like that.

If any changes made in mapplets it automatically inherited in all other instance mapplets.

Source table has 5 rows. Rank in rank transformation is set to 10. How many rows the rank transformation will output?

5 Rank.

What is bitmap index?

A bitmap for each key value replaces a list of rowids. Bitmap index more efficient for data warehousing because low cardinality, low updates, very efficient for where class.

Why need staging area database for DWH?

Staging area needs to clean operational data before loading into data warehouse.

Cleaning in the sense your merging data which comes from different source

What is slowly changing dimension?

Dimension attribute values may change constantly over the time. (Say for example customer dimension has customer_id,name, and address) customer address may change over time.

What is difference between primary key and unique key constraints?

Primary key maintains uniqueness and not null values Where as unique constrains maintain unique values and null values.

What are the different uses of a repository manager?

Repository manager used to create repository which contains metadata the informatica uses to transform data from source to target. And also it use to create informatica user’s and folders and copy, backup and restore the repository.

For indepth understanding Cognos Training click on