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Cognos Interview Questions
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 are the tiers of the Report Net Architecture?
The Report Net architecture can be separated into three tiers:
* Web server
* Applications
* Data
Define Business Intelligence
Business Intelligence is a broad category of application programs and technology used for query,
Reporting and analyzing the business multi dimensionally.
What is a Data Mart?
A Data Mart is a subset of a data warehouse that can provide data for reporting and analysis.
What is HPQS ?
Data Marts are sometimes also called as HPQS (Higher Performance Query Structure).
What is multi dimension analysis?
It is a technique to modify the data so that the data can be view at the different levels of details.
What are the responsibilities of Cognos Administrator?
A Cognos Administrator is assigned with following responsibilities.
1. Installations and configurations in distributed network environment.
2. Creating the Repository (Content Store). 3. Perform back up and recovery of Meta Data.4.
Developing the user Administration.5. Tuning the servers.6. Deployment.
Responsibility of Cognos Architect?
An Architect is responsible for designing the interface by fulfilling the user requirements. Once the
interface has been designed it should be rigorously tested before distributing to the end user
population.
Roles of the Application Developer?
Design the Reports according to the Report requirement templates.
Testing the each report with the following types of tests.
a. Unit Testing b. System Testing c. Performance Testing
What is OLAP?
OLAP stands for Online Analytical Processing. It uses database tables (Fact and Dimension tables) to
enable multidimensional viewing, analysis and querying of large amount of data.
What are the components of Report Net?
Framework manager ,Cognos connection, Query Studio, Report Studio
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?
Insert table Objects pane > Properties pane > Explorer bar >Report Viewer
What is Snap Shot?
snapshot is a static data source it is a picture of report once u created a snapshot report u
can't add a data item.
How do you define a cube?
Its a multidimensional view of dimension and measures. It is used to analyze the data in
various aspects, which is called slicing and dicing.
What is the Difference between Power Play transformer and power play reports?
Power play transformer' is an ‘MOLAP’ tool using which one can create multi dimensional
structure called “CUBE”.
Power play 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 our project requirements.
What is transformer?
Transformer is used for building the Cubes (Multidimensional Structure used for OLAP
What are the types of OLAPs?
1. DOLAP:-The OLAP tool which works with desktop databases are called as DOLAP
Ex:- FoxPro, Clipper, Dbase, Paradox.
2. ROLAP:-The OLAP tool, which works with Relational databases, are called as ROLAP.
Ex:-Oracle, SQL Server, Tera Data, DB2.
3. MOLAP: - The OLAP tool, which works with Multidimensional databases, are called as MOLAP.
Ex:- ESSBASE, Power Cube
4. HOLAP:- The OLAP tool which works with Relational databases and Multidimensional database,
are called as MOLAP.
Ex:- Cognos, Business Objects.
What is OLTP?
OLTP stands for Online Transaction Processing. Except data warehouse databases the other
databases are OLTPs. These OLTP databases are designed for recording the daily operations and
transactions of a business.
What is an Interface?
An Interface is a gateway between the user and database.
An Interface contains a logical pointers which pointes to data in the Data Warehouse.
An Interface is isolates the complexity and diversity if data bases.
A good OLAP Interface writes an efficient SQL read on accurate data from database.
An Interface needs to be designed by fulfilling the report requirement.
What is the role of a Data Warehouse in creating the Interface?
Data Warehouse acts as Source to the Interface.
What are the types of components installed while loading the Cognos Report Net Software?
When we install the Cognos Report Net Software there are two types of components get installed :1. Windows based components. 2. Web based components.
Define Windows based components?
A Framework manager is windows based modelling tool used for creating a project (interface).
Define Web based Components?
The following are the web based components.
A. Cognos connection B. Query Studio C. Report Studio D. Analysis Studio
Components of Report Net:
1. Framework manager.2. Cognos connection 3. Query Studio 4. Report Studio 5.Transformer
6. Analysis Studio
What are the phases of the Cognos Report Net Workflow?
Plan, Manage, Model, Author, Consume.
What are the advanced features of Report Net?
The Cognos Report Net has multilingual database accessibility.
The parameter maps are key value phase, which are used for working with local Language that the
default value is ‘EN’.
What is Framework manager?
Frame Work Manager is windows based metadata development or metadata modelling tool for
Cognos Report Net.
Why we need Framework manager?
To create the interface known as Project.
To create model the metadata derived from one or more data sources
How a project appears in a Framework manager?
A frame work manager project appears as a folder that contains a project file (.cpf) and the specific
XML files that define the project.
What are the Building Blocks in Frame Work Manager?
The Query subjects are called Building Blocks in Framework Manager.
What are phases the workflow process consists in Framework Manager?
The workflow process consists of the following phases:
* Design and create project > * Prepare Metadata >* Prepare the Business View
* Create and Manger Packages >* Set Security > * Publish >* Manage the Project
How you set the security Framework manager?
To set the security you have to set as:* Define access to packages. >* Create security filters > *
Define access to objects >* Define package administration access
Define Name Space?
In security, a collection of user accounts and user groups from an authentication provider. A Name
Space is a container, which holds the Query Subjects.A Name Space uniquely represents the Query
Subjects.
Can you delete Cognos namespace?
No, we cannot delete Cognos namespace
What is the Cognos Namespace? And what it contains?
The Cognos namespace is the ReportNet built-in namespace
It contains Cognos objects:
Groups , Roles, Sources, Distribution lists, Contacts
What are the Groups and Roles?
Groups and roles represent collections of users that perform similar tasks.
What is Folder?
A Folder is used to organize the Query Subjects.
Define Relationship?
A Relationship is a connection that explains how the data in one Query Subject relates to data in
other Query Subjects.
What is a Package?
A container for models, reports, and so on. Modellers create packages in Framework Manager to
publish models to the ReportNet server.
What is Physical layer?
The Physical layer provides the physical query layer and is made up primarily of data source and
stored procedure query subjects. It acts as the foundation for the presentation layer.
What is Presentation layer?
The Presentation layer makes it easier for report authors to find and understand their data. The
Presentation layer is made up primarily of model query subjects that you create.
Define function set:
A function set is a collection of vendor specific database.
The Expression editor lists the function sets for all available vendors. However, you can restrict the
function sets, so that it lists only the vendors that you want to use in your project.
What is a Metadata?
Data about data is called as Metadata. The Metadata contains the definition of a data.
What is a Project?
When we work with a framework manager you work in a project.
Project is a set of metadata organized for Report Authors according to the Business rules and
Model.
A Project created appears as folder, which contains following files.
a. Project Name .CPF (Cognos Project File) > b. Model .XML > c. Preferences .XML
d. Custom data .XML >The files in the folder are unique to that Project.
Define Publish?
To transfer all or part of a Framework Manager model to the ReportNet server, so that report
authors can use it.
What a Project contains?
A. A Model > B. Namespaces > C. Data sources > D. Parameter maps > E. Packages
F. Folders > G. Query Subject > H. Query Item >I. Relation ship
What is a Model?
A model in Frame work manager is a business presentation of the structure of the data from one or
more databases. Or A model is a set of related query subjects and other objects.
What are Dimensions?
Dimensions are categories by which summarized data can be viewed.
What are Confirmed Dimensions?
The Dimensions which are reusable and fixed in nature.
What are Fact Tables?
A Fact Table is a table that contains summarized numerical (facts) and historical data. This Fact
Table has a foreign key – primary key relation with a dimension table.
What are the types of Facts?
The types of Facts are:
1. Additive Facts:- A Fact which can be summed up for any of the dimension available in the Fact
Table.
2. Semi-Additive Facts:- A Fact which can be summed up to a few dimensions and not for all
dimensions and not for all dimensions available in the Fact Table.
3. Non-Additive Fact:- a fact which cannot be summed up for any of the dimensions available in the
Fact Table.
Define Query?
A description of the data to be retrieved from a database.
Explain about Data Source Query Subject?
Data Source query subjects contain SQL statements the directly reference data in a single data
source. Frame work manager automatically creates a data source query subject for each table and
view that you import into model.
When the default data source query subject is created?
During the initial metadata import operation, a default data source query subject is created for each
object you select (for example table) and creates the default relationships between query subjects
for you automatically.
How can you edit the data source query subject?
i. Apply or embed a filter > ii. Apply or embed a calculation > iii. Insert a Macro
iv. Insert a data source reference. > v. Change the SQL type. > vi. Change how SQL is generated.
>These all are we can find it in “Edit definition window”.
What are the types of SQL?
SQL is the industry language for creating, updating and querying relational data base management
system. Types of SQL.
1. Cognos SQL 2. Native SQL 3. Pass-through SQL.
Define Cognos SQL?
By default Cognos FM uses Cognos SQL to create and edit Query subjects.
Advantages:
1. Can contain metadata from multiple data sources. 2. Have fewer database restrictions 3. Interact
more effectively with Cognos applications.
Disadvantages:
You can not enter nonstandard SQL.
Define Native SQL?
Native SQL is the SQL, the data source uses, such as Oracle SQL, but you cannot uses Native SQL in a
query subject that references more than one data source in the project.
Advantages:
1. Performance is optimized across all related query subjects.
2. You can use SQL that is specific to your database.
Disadvantages:
1. You cannot use SQL that the data source does not support for sub queries.
2. The query subject may not work on different database type.
Define Pass-Through SQL?
Pass-Through SQL lets you use native SQL without any of the restrictions the data source imposes
on sub queries.
Advantages:
1. You can enter any SQL supported by the database.
Disadvantages:
1. There is no opportunity for Frame work manager to automatically optimize performance. The SQL
may not work on a different data source.
What are Query Processing Types?
There are two types of query processing.
1. Limited Local: The database server does as much of the SQL processing and Execution as possible.
However, some reports or report sections use local SQL processing.
2. Database only: The database server does all the SQL processing and execution with the exception
of tasks not supported by the database. An error appears if any reports of report sections require
local SQL processing.
What is Query Subject?
A Query Subject maps to the table in the database.
A Query Subject uses an SQL to retrieve the data from the data source.
A Query Subject is also known as Business View.
What are the types of Query subjects?
1. Default data source query subjects 2. Model Query Subjects
3. Stored Query subjects
What is a Query Item?
A query Item maps to columns to the database table. A Query Subject contains Query Items.
How can you restrict the tables retrieved by a query?
By setting governors we can restrict the tables.
What is meant by Governors?
To apply privileges and restrictions for a user class. Governor settings are used to set restrictions on
queries by user class, such as
1. Sorting on non-indexed columns 2. Outer joins 3. Suppress duplicates 4. Cross-product queries 5.
Retrieval of large text items 6. Number of records 7. Number of tables 8. Query execution time
What is a User Class?
A defined group of users with the same data access needs, privileges and restrictions.
What is Scrubbing at Project level?
According to the report requirements derive the new Items with the help of existing Query Items.
This process is known as Scrubbing at Project level.
How can you add the calculated data to a report?
a. Summarize existing detail values predefined summary functions (such as sum, avg)
b. Create new report items using data from existing report items.
c. Use model calculations provided in the package.
What are the sources to create new Query subjects?
A new Query Subject can be created from the following sources.
1. Model (Query subjects & Query Items) 2. Data Sources (Tables and Columns)
3. Stored Procedure.
What is Multi Database Access in Cognos Report Net?
In Cognos Report Net a Project can be created from multiple databases. The databases can be either
homogenous or hydrogenous.
What are Parameter Maps?
A Parameter Map is a key value pair used in creation of conditional Query Subjects.
A Parameter map sub situates the values at the query at runtime.
What is the default formats of reports?
HTML, PDF, CSV, and XML.
What are the different ways to modify multi lingual metadata?
1. Macro :- To modify dynamically
2. Directly
What is a Macro?
A Macro is a runtime object, which uses the parameter maps and session parameters in developing
the conditional query subjects.
What is usage property? And what are different setting to set usage property?
It identifies the intended use for the data represented by each query item.
It determines the aggregation rules of query items and calculations.
The different usage property settings are:
* Identifies * Fact * Attribute * Unknown
What are the types of filters in Framework manager?
In framework manager we can create two types of filters.
1. Model filters 2. Query filters.
Define Model Filter?
A filter is a condition used to restrict the data displayed in the Report.
Model filter are reusable.
Define Data restriction:
A filter is a condition, which restricts the amount of data displayed in the report.
What is condition?
An expression that yields a Boolean value. Conditions are used in query expressions, query filters,
and Boolean report variables that can be used for conditional formatting, styles, data sources,
layouts and blocks.
Types of Conditions:
Conditions are of 2 types:
1. Static Condition: - Condition doesn’t change whenever you run the report.
2. Dynamic Condition: -A condition can be kept on change whenever you run the report.
What are the types of filters in Report Studio?
In the report studio we can find two types of filters.
1. Tabular Filters:- These filters are two types
a. Summary Filters b. Detailed Filters
2. Grouped Filter
What is a Loop?
A Loop is a closed path which is resulted due to joints.
A Loop causes performance degradation of query execution and wrong data will be displayed in the
report.
A Loop can be resolved by creating the short cuts (Alias).
What is Alias Table?
An alternative name for a table generally used in self joins
What are the uses of Alias Table?
The uses of Alias Table are :1. To resolve the Loops. 2. To create self-joins with in a table. 3. To
Provide alternate join structure.
What is Associated Data Item?
A Data Item linked to the group data item. Associated data item suppress duplicate data values but
do not generate a control break. The associated column displays only one data values for the group
with which it is associated.
What is Automatic Association?
The group association of a newly created summary. The location of the group where you create the
summary determines its automatic association.
What is an Ambiguous Relationship?
An ambiguous relationship is where there are multiple relationship paths between one or more
query subjects leaving multiple options for how to write a query.
What is a Join and types of Joins?
A Join identifies the columns from one table that are used to link to another table.
A Join is commonly formed by a foreign key definition within the database.
Types of Joins :- 1. Equi-joins 2. Non equi-joins 3. Outer joins
What is a dimension?
A broad grouping of descriptive data about a major aspect of a business, such as products, dates, or
markets. Each dimension includes different levels of members in one or more hierarchies, and an
optional set of calculated members.
What is a Confirmed Dimension?
If a Dimension is connected to multiple fact tables then it is called as Confirmed Dimension.
What is a Junk Dimension?
A randomly used dimension is Junk Dimension.
Define Surrogate Key?
It has system-generated artificial primary key values, which allows to maintain historical records in
the Data Warehouse more effectively.
What are the User Interface Components?
* Cognos Connection * Report Studio * Query Studio * Frame work manager
* Cognos configuration
What is significance of Framework Manager in Cognos Reporting?
ANS: Framework Manager is a metadata modelling tool. A model is a business presentation of the
information in one or more data sources. When you add security and multilingual capabilities to this
business presentation, one model can serve the reporting, ad hoc querying, and analysis needs of
many groups of users.
What is loop in framework manager?
ANS: Loop is closed path in IN FRAME WORK MANAGER DUE TO JOINS report net it called as
ambiguous relationship. That means a query subject contains multiple paths to retrieve the data. It is
an exception to resolve to create a shortcut on that query subject otherwise it displays wrong results
in reports and performance is degrades. An undefined join between two tables is known as loop. To
resolve loop delete the joins, if these joins are necessary then we have to create shortcuts nothing
but alias tables. Place the joins in alias tables.
What are the filters in Framework Manager and Report Studio?
ANS: Filters in framework manager are
1. Standalone filters 2. Embedded filters
Report studio Filters are
1. Detail filters 2. Summary filters
How to import two data sources into Framework Manager?
We can import two data sources to FM in the Run Metadata Wizard.
Go to Run Metadata Wizard–>Select another database ( e.g. suppose SQL Server is choosed in prior
attempt, then u can choose Oracle as new datasource).Then import it
How to perform single sign on in Cognos by using URL?
In Cognos configuration under authentication allow anonymous access should be false. In cgi-bin
properties (under iis) the enable anonymous access should be false.
What is usage property? Where do we set usage property?
1.The Usage Property identifies the use for the data represented by query item.
It determines the aggregation rules of query items and calculations.
The different usage property settings are Identifier, Fact, Attribute, Unknown
2. To set the usage property: Click the query item u want to set the usage property for Then click the
properties icon on the tool bar or you can see the properties pane on the right side of the browser.
Go to “USAGE” tab and click “CLICK TO EDIT” option. And select the appropriate.
What is the use of prompts in Framework Manager?
ANS: Use of Prompt in Framework Manager:
Filter on query subject – to restrict the rows that are returned by filtering out the unwanted data by
creating one or more embedded filters for query subject.
Prompt in filter with usage set to always – user need to supply a value to filter.
Where exactly determinants are used in cognos framework manager?
ANS: A query subject that behaves as a dimension has multiple levels of granularity and will be
joined on different sets of keys to fact data.
How would you structure your Framework Manager Model?
ANS: A model is normally structured into two layers/views. Database/ Physical view and Business/
Presentation view. These can be implemented using Namespaces.
You import the metadata into Physical layer from DB using data source connection. You will use
Import Metadata Wizard. You will change the Query Subjects & Query Items, create relationships
(joins) and other activities here.
In the Presentation layer, you create Query Subjects taking input from the existing Physical layer.
You change the names of the Query Items and other cosmetic modifications. You can choose only
the Presentation layer while creating the Packages and apply appropriate security settings.
How to provide security in frame work manager for a query subject?
ANS: Procedure for providing security for query subject in frame work manager is:
Select querysubject -> in properties pane select ->security filters (click on edit)a specify data security
wizard appears->click on add groups -> cognosnamesspace(select users and groups wizard opens)
How can we generate the cubes in framework manager?
ANS: You can create the IQD file from framework manager.
This IQD file will be used by Transformer to create the cube.
How to generate IQD file from framework manager?
Create a Query Subject, from the properties pane select externalise, there we have 4 options in that
select IQD.
What is catalogue and types of catalogues in cagonos?
A catalogue is a file containing the information (Database tables) that Impromptu users
need to create reports. > personal > distributed > hared > secured
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 catalogue?
Multiple database could not be connected in a single catalogue. So that we use hot file
for this purpose.
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's related to the at particular report, we use snapshot when ever we want to
compare reports.(Example :we want to compare this months report with previous
months).
Define data stores in Cognos?
Data sources, also known as query databases, are relational databases, dimensional
cubes, files, or other physical data stores that can be accessed through IBM Cognos8.
Application Tier Components use data source connections to access data sources.
What is metric store database?
A metric store database is a special case of a query database. A metric store database is
used to store the information associated with metrics that appear in scorecards,
including targets performance metrics , thresholds , membership in scorecards
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 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.
Folder contains repository objects such as sources, targets, mappings, transformation
which are helps logically organize our data warehouse.
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 centre?
Using power centre 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 row ids. 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 types of index?
Bitmap index ,B-tree index, Function based index ,reverse key and composite index. We
used Bitmap index in our project for better performance.
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.
What are shortcuts? Where it can be used? What are the advantages?
There are 2 shortcuts(Local and global) Local used in local repository and global used in
global repository. The advantage is reuse an object without creating multiple objects.
Say for example a source definition want to use in 10 mappings in 10 different folder
without creating 10 multiple source you create 10 shortcuts.