If you are passionate about taking your career into Cognos, well it's a lucrative career option available in today’s IT world. We are here to help you out in clearing your Cognos interview. For this, we have created a list of top 60 Cognos Interview Questions and Answers from industry experts for both freshers and experienced.

Have a look at our Cognos interview questions to double your chances of getting hired in this rapidly advancing domain.

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IBM Cognos Interview Questions for Beginners - Updated 2020

Q1) What is Cognos tool?

Ans. Cognos is IBM’s business intelligence and performance management software suite.

This tool is specially designed for enabling non-technical personnel in large enterprises to extract corporate data, analyse them and provide reports to help businesses with informed decisions.

Q2) What is the Cognos Query Item?

Ans. Query item is majorly used for reporting. It is also an essential object for framework managers. They are quite similar to subsets of query subjects.

In simple words, a query item is an object in the model that is actually placed in the report. It symbolizes a single instance of a specific thing such as data when that particular product was introduced.

  • For the purpose of relational metadata, we can modify properties of query items by:
  • Setting usage and regular aggregate properties for following the intended use of the query item.
  • understanding how data is displayed in a report and format query items.
  • Recognizing column as a prompt, and know-how prompt information is displayed to the users.

Q3) What do you mean by Cardinality in Cognos?

Ans. Cardinality is defined as a relationship between the queries or tables. IBM Cognos supports both minimum-maximum cardinality and optional cardinality.

The relationship that can be formed between the tables are:

  • One to One
  • One to Many
  • Many to Many
  • Many to One

Q4) What are the different types of prompts available in Cognos?

Ans. Various types of prompts are available in Cognos, such as:

  • Text Box prompt
  • Value prompt
  • Search prompt
  • Date prompt
  • Time prompt

Q5) List the types of gateways used in Cognos.

Ans. IBM Cognos supports various types of gateways, including:

  • ISAPI - This is used for Microsoft Internet Information Services (IIS) Web server and delivers faster performance for IIS.
  • Apache_mod - This is used with Apache Web server.
  • Servlet - This is used for the application server or web server supporting servlets.
  • CGI - This is the default gateway used for all supported Web servers except in production environments.

Q6) What is the difference between macros and prompt?

Ans. Macro is a combination of instructions that executes the applications. It is a dynamic object used for querying substitute values at run time.  

A prompt decides the manner in which report data should be displayed. It is defined either in catalog generation or report generation.

Q7) What is Cognos Dynamic Cube? And when to use it?

Ans.  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 analyse 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.

Q8)  Explain Dynamic Cube Lifecycle in Cognos?

Ans. 

  1. Model and Publish (Warehouse and CM)
  2. Deploy and Manage (Dynamic Cube Server, CM)
  3. Reporting and Analytics (Dynamic cube, Logs)
  4. Optimize (Warehouse, CM, Logs)

Q9) What is Cognos Cube Designer?

Ans. 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.

Q10) Explain Cognos Cube Designer modeling workflow.

Ans. First model your cube definition in Cognos Cube Designer

Create Dynamic cube

Deploy your dynamic cube to BI server

Q11) How to administrate Dynamic cube?

Ans. 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

Q12)  List the types of hierarchies.

Ans. There are two types of hierarchies in Analysis Services:

  • One is Attribute hierarchies
  • Second is User-defined hierarchies.

Q13) What are all the components of Report Studio? 

Ans. Following are the components of Report Studio:

  • Objects panel
  • Properties panel
  • Explorer bar
  • Report Viewer

Q14) What do you mean by Aggregate Advisor?

Ans. 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. 

Q15) Define drill through report.

Ans. 

Drill through reports are used for connecting two or more reports by linking

related data items. It has a parent and child relationship between the reports.

Q16) What is a Framework Manager?

Ans. 

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.

Q17) Describe Cognos Access Manager.

Ans. 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. 

Q18) Explain Query Studio.

Ans. In Cognos, Query Studio is used for the purpose of creating queries and reports.

Following functions can be performed using Query Studio:

  • Viewing Data 
  • Creating BI Reports 
  • Changing Existing Reports  
  • Data Customization in Report  

Q19) What are the types of reports available in Query Studio?

Ans. Various types of reports are supported by Query Studio to meet business requirements.

  • List Reports − These reports are used for showing the entire customer base.
  • Crosstab Reports − These are used for showing quantity sold with product and region on a different axis.
  • Charts − In this, we can insert charts for showing data graphically. We can also combine a chart with a Crosstab or with a list report.

Q20) Explain about Aggregate Cache.

Ans. 

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.

Q21) What is Cognos ReportNet?

Ans. Cognos ReportNet 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 ReportNet are the following:

  • Cognos connection
  • Framework manager
  • Report Studio
  • Query Studio

Q22) What is the difference between Embedded filters and standalone filters?

Ans. 

  • 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.

Q23) What is DTM?

Ans. 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.

Q24) Describe fact tables.

Ans. 

A fact table is a kind of a table in the database which includes facts and foreign keys.

Actually, these keys are utilised for connecting to several dimension tables such as time, product, etc.

Facts are used to measure like revenue, account balance, and more. Foreign key derives the primary key relation with a dimension table.

Summarized numerical and historical data is stored in fact tables. 

Types of Fact Tables: 

  • Factless Fact Tables - The fact table which does not contain any measure is called a factless fact table. It contains keys from various dimension tables. Often used to resolve a many-to-many cardinality issue.
  • Centipede Fact Table - The centipede fact table is a normalized fact table. Here, the normalizer decides the fact rather than snowflaking dimensions tables.
  • Conformed Fact Tables - They are measures re-used across multiple dimension models.

Q25) List the types of facts.

Ans. 

Following are the types of facts:

Additive - This can be used with any aggregation function like Sum(), Avg() etc.

Non-Additive - We are not able to use numeric aggregation functions such as Sum(), Avg() etc on Non-additive facts.

Semi Additive - These facts are those where only a few aggregation functions can be applied.

Q26) What is the difference between a physical layer and an application layer?

Ans. 

Physical Layer - It is primarily made of stored procedure query subjects and data source. It serves as a foundation for the presentation layer.

Presentation Layer - It is primarily made of model query subjects created by us.

Q27) What do you mean by query subjects?

Ans. 

A Query subject is a collection of query items which have an inherent relationship. For modifying query objects, we use IBM Cognos Framework Manager to optimize and customize the data they retrieve.

  • Various types of query subjects are supported by the framework manager, such as:  
  • Data source query subjects
  • Model query subjects
  • Stored procedure query subjects

Q28) What is the difference between static and dynamic conditions?

Ans.

  • Static Condition - Whenever you run the report, the condition will not change.
  • Dynamic Condition - Condition which keeps on changing whenever you run the report

Q29) What is Cognos Powerhouse? And why is it used?

Ans. 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.

Q30) What are the initial page components of a Cognos Connection?

Ans.  Following are the initial page components of a Cognos connection:

The Utilities Toolbar

The Studio Toolbar

The Tab Navigator

Q31) What are all types of Batches in Cognos?

Ans. Types of Batches available in Cognos are listed below:

Sequential – It runs the sessions one by one

Concurrent  – It runs the sessions simultaneously

Q32) What is the difference between cascading report and drill through the report?

Ans. Cascading report means extracting data from one prompt using the values of another prompt.

Drill through report means extracting data by selecting a column in a report.  It means getting the detailed information by clicking that column data.

Q33) How is Standard different from Metrics folder?

Ans. 

  • Standard Folder  –  This is a container of all folders particularly used for organizational purposes. It is yellow in color and acts as a local computer folder.
  • Metrics Folder  – This folder is used for storing metric related data. It is dark blue in color and it is directly opened in Metrics studio.

Q34) What is Cognos Configuration.

Ans. Cognos Configuration is used to configure IBM Cognos Business Intelligence while installing and configuring components and also to start and stop IBM Cognos services.

Q35) How is drill-up different from the drill-down report?

Ans. Drill up is used to remove grouping columns from the dimension tables, whereas drill-down is used to add group columns from the dimension tables.

Q36) Explain Dimensional Schema.

Ans. dimensional Schema divides the measures which quantify the business from the descriptive elements that define and classify the business physically. The dimensional schema is a logical or physical schema. In the logical dimensional schema, the measures, fact, and dimensions are denoted as attributes and entities that are database vendor-independent and therefore can be converted to a physical dimensional schema for any database vendor. A physical dimensional schema is denoted in the form of snowflake or star schema, where objects are the database tables.

Star schemas - It is a relational dimensional database type composed of a central, single fact table enclosed by dimensional tables.

Snowflake schemas - In encompasses one fact table that is connected to many dimension tables. These can also be connected to other dimension tables through a many-to-one relationship. 

Starflake schemas - It’s a combination of Star and Snowflake schemas.

Many-to-one relationships - It refers to one entity or table containing values and refers to another entity or table containing unique values.

Q37) Explain Dynamic cube modeling?

Ans. 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.

Q38) What is warehouse cubing?

Ans.  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.

Q39) What is the difference between star schema and snowflake schema?

Ans.  Star and Snowflake schemas are used for dividing facts and dimensions into separate tables. Snowflake schemas further separate the different levels of a hierarchy into separate tables.

Star schemas - It is a type of relational database schema that is composed of a single, central fact table surrounded by dimension tables.

Snowflake schemas - It can also refer to as snowflake join schema, that consists of one Fact table connected to many dimension tables, which can be connected to other dimension tables.

Q40) What are the different types of securities that we can apply in framework manager?

Ans. Different types of security available in IBM Cognos Framework Manager are the following:

Row-level security: It enables you to create a security filter and use it to a particular query subject. It also controls the data that is shown to the users during building and running their reports.

Object-level security: It enables you to secure an object directly by allowing or refusing users access to the objects, or also by concealing it all from the users. 

Package level security: It lets you apply security to a package and detects who all has access to that particular package.

Q41) How is the model different from a package in framework manager?

Ans. A model assists as an insulating layer between IBM Cognos BI reporting users and the database. While a package is a model subset, ensures users are furnished with the appropriate data for the reporting they need to do, and also the data structured will make a sense from the business perspective.

Q42) What is the extension of the framework manager project file?

Ans. The extension of the framework manager project file is .cpf ( Cognos Project File ).

Q43) What is tm1 Web?

Ans. TM1 web uses a multi-tiered architecture to allow users access and interact with Cognos TM1 data with any of the supported web browser.  TM1 Web multi-tiered architecture contains a web application server, data component tiers, and a web client.

Wen application server: Cognos TM1 web operates on Microsoft Internet Information Services (IIS) web server and needs a Microsoft.NET framework

Data: This includes Cognos TM1 Admin Server and at least one Cognos TM1 Server.

Web Clients: This allows users to access and connect using any of the web browsers with the Cognos TM1 data.

Q44) What is the difference between TM1 Architect and TM1 perspective?

Ans. TM1 Architect is a desktop application runs in a remote desktop session with IBM Planning Analytics system, whereas, TM1 perspective is an add-in for Microsoft Excel runs in a remote desktop session with IBM Planning Analytics system.

Q45) Explain the Cognos Controller.

Ans. The Financial consolidation software used for complete close, consolidate, and report process is called a Cognos Controller. It serves you to automate and accelerate the close process with a  full suite of financial consolidation software, especially for finance users. 

Also, enables you to deliver complete financial results, build financial and management reports, and give the chief financial officer (CFO) with an enterprise view of key financial metrics and ratios.

Q46) What is Cognos Planning?

Ans. Cognos planning is a finance manged solution used for both the business planning and operational with the adaptability to turn the most complicated procedure into 

Strategic plans, forecasts, and budgets.

Q47) What is the use of Cognos Impromptu?

Ans. Cognos Impromptu is an intuitive, user-friendly system allows non-technical personnel to design and share business intelligence reports easily and faster. This system is associated with the CruiseNet core system and allows to build customized reports varying from simple lists to series of linked and interactive reports.

Q48) What do you mean by Dynamic Query Mode?

Ans. The dynamic query mode allows data source and query optimizations to resolve query complexity, timeless expectations, and huge data volumes with enhanced query execution techniques. For relational and OLAP data sources, we can use dynamic query mode.

The following are the benefits of using dynamic query mode:

Creates models and publishes packages to IBM Cognos Analytics

  • Enforces consistent modeling and reporting best practices
  • In-memory caching
  • Enhanced null suppression
  • Member ordering
  • Optimizes joins by applying filters
  • Creates a bridge table to link separate data sets 
  • Stored procedures transaction access

Q49) What is the SQL Generation?

Ans. We can specify how the Cognos framework manager generates the SQL that recollects the data from the relational data sources for model query subjects or data source query subjects.

The SQL Generation type of a query subject can be set to either view or minimized. But minimized is set to be by default.

If the generation type is set to as minimized, the generated  SQL includes only a minimal set of tables and joins required to access values for the selected query items.

If the generation type is set to As View, the framework manager contains the full SQL statement that described the query subject.

Q50) Explain Query Generation.

Ans. 

  • Framework manager uses Cognos SQL for creating query subject, by default.
  • For classic query mode, native SQL optimized for the data source at runtime is generated and passed down to the data source.
  • Relational Query Planner prepares the query and then passes it off to Universal Data Access.
  • Universal Data Access component has a series of gateway files that control SQL generation for particular RDBMS (DB2, Oracle, MS SQL Server, etc)
  • UDA makes the native SQL and performs it against the RDBMS
  • Copy of the query engine local in the Framework Manager install
  • Used for importing metadata, generating SQL, testing query subject,  and expression validations.
  • In Dynamic Query Mode, requests are sent to the Query Service for processing
  • No query service running locally on the FM side
  • Framework Manager will include passing the necessary elements in the model to Query Service on the server
  • Result set and generated SQL for the query will be part of the response back to FM.
  • This is the case testing objects and evaluating expression

Q51) What is the difference between Measure and Regular Dimension?

Ans. A measure dimension is a set of facts that are created from one or more query subjects possessing a valid relationship between them.

A regular dimension includes one or more user-defined hierarchies, with each hierarchy consisting of the levels, captions, keys, and attributes.

Q52) What is the use of Model Advisor?

Ans. The model advisor is used when creating a framework model to identify the model that follows the best modeling practice and also the areas that needs to be examined and changed. We can run a model advisor against a complete model or a subset of the model. We can even choose the tests which need to be run against the model.

Q53) Explain the Dimensional Modeling for Report and Analysis?

Ans. 

  • DMR (Dimensionally Modeled Relational) builds in classic query mode.
  • Logical dimensional layer over top of a relational model
  • Single measure dimension and one or multiple regular dimensions
  • Enables drill-up/drill-down analysis in the studios
  • Dimension layer can be applied over any star schema model.
  • Dimensions and measure dimensions are constructed from model query subjects or database query subjects
  • At runtime, queries are run to spin a virtual cube on disk to simulate the OLAP style analysis capabilitie

Q54) What are the Determinants? And when should use them?

Ans. Determinants are used for providing control over granularity while aggregating. Through identifying groups or subsets of data in a query subject, it reflects granularity.

Framework manager uses it to determine the levels in a default hierarchy for auto-generating regular dimensions from query subjects. 

The determinants should be used when:

  • Dimensions connect to fact tables at levels of granularity that posses repeating keys.
  • There is a requirement to count or execute aggregate functions on an attribute or a ket that is repeated.
  • Avoiding a distinct clause on distinct keys.

Q55) How Framework Manager uses Cardinality?

Ans. Query engine uses cardinality to identify query subjects that act as dimensions and facts, to avoid double-counting fact data, and support loop joins in star schema models. 

Cardinality implies dimension side on the 1 side and fact data on n side.

Q56) Explain about Message Flows?

Ans. The message flow is an order of processing steps that run in the integration node when an input message is received. It contains an input node to represent the sources of the messages that are processed.

We can process the message in one or more ways and deliver it through one or more output nodes. Before a message delivered to a final destination, it is transformed back into a bitstream.

Q57) What is a User Class in Cognos?

Ans. User class is an object that describes the section of users who possess similar functions. Cognos supports user access manager for controlling user access like PowerPlay, Impromptu web reports, etc. every member of a user class has similar access privileges, and users can be assigned to various user classes.

Q58) What is a Snapshot?

Ans. A snapshot is produced for copying the exact data that is associated with the current report and also used for comparing it with other reports.

 

Q59) Name the types of indexes that are supported by Cognos?

Ans. Various types of indexes supported by Cognos are:

  • Bitmap index
  • Function based index
  • B-tree index
  • Reverse key and composite index

 

Q60) What are Confirmed Dimensions? 

Ans. Confirmed dimensions are single dimensions which are delivered once using a dimension build and can be shared over various data marts.

If you have attended any Cognos interview in the recent past or maybe I have missed any topic you want to know. Either way, let me know by leaving a comment below right now.

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