Informatica MDM Interview Question and Answers
Q1) What is MDM?
Ans: Master data management (MDM) is a comprehensive method of enabling an enterprise to link all of its critical data to one file, called a master file, that provides a common point of reference. When properly done, MDM streamlines data sharing among personnel and departments.
Q2) Has MDM gone mainstream? Do people “get it?”
- There is a huge awareness of MDM. Gartner recently hosted an MDM conference for the first time [piggy-backing on its CRM conference], and they pulled in about 500 attendees.
- As to whether they “get it,” it depends on who you're talking to. Most of the IT people get it. Business users understand the moniker, but they might or might not understand MDM quite as well. I find that business users often require education in terms of what it can do for them and what value it brings. With IT people, it’s a different conversation; they want to know more about the features and how we differentiate ourselves from the competition.
Q3) Are you seeing awareness translate into bigger budgets for MDM?
Ans: It's a matter of awareness and the problem becoming urgent. We are seeing budgets increased and greater success in closing deals, particularly in the pharmaceutical and financial services industries. For rester predicts MDM will be $6 billion markets by 2010, which is a 60-percent growth rate over the $1 billion MDM market last year. Gartner forecasts that 70 percent of Global 2000 companies will have an MDM solution by the year 2010. These are pretty big numbers.
Q4) What are the biggest technical and management challenges in adopting MDM?
Ans: Technical folks often have a challenge in data governance in selling the project and getting the funding. Management is looking for a return on investment; they need MDM tied to quantifiable benefits that business leaders understand, like dollar amounts around ROI.
Q5) What is Data Warehousing?
Ans: A data warehouse is the main repository of an organization’s historical data, its corporate memory. It contains the raw material for the management’s decision support system. The critical factor leading to the use of a data warehouse is that a data analyst can perform complex queries and analysis, such as data mining, on the information without slowing down the operational systems. Data warehousing collection of data designed to support management decision making. Data warehouses contain a wide variety of data that present a coherent picture of business conditions at a single point in time. It is a repository of integrated information, available for queries and analysis.
Q6) What are the fundamental stages of Data Warehousing?
Offline Operational Databases – Data warehouses in this initial stage are developed by simply copying the database of an operational system to an off-line server where the processing load of reporting does not impact on the operational system’s performance.
Offline Data Warehouse – Data warehouses in this stage of evolution are updated on a regular time cycle (usually daily, weekly or monthly) from the operational systems, and the data is stored in an integrated reporting-oriented data structure.
Real-Time Data Warehouse – Data warehouses at this stage are updated on a transaction or event basis, every time an operational system performs a transaction (e.g. an order or a delivery or a booking, etc.)
Integrated Data Warehouse – Data warehouses at this stage are used to generate activity or transactions that are passed back into the operational systems for use in the daily activity of the organization.
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Q7) What is Dimensional Modeling?
Ans: Dimensional data model concept involves two types of tables and it is different from the 3rd normal form. This concept uses the Facts table which contains the measurements of the business and the Dimension table which contains the context(dimension of calculation) of the measurements.
Q8) What is Informatica PowerCenter?
Ans: Powercenter is the data integration software of Informatica Corporation which provides an environment that allows loading of data into a centralized location such as a data warehouse. Data can be extracted from multiple sources that can be transformed according to business logic and can be loaded into files and relation targets.
Q9) What are the components of Informatica PowerCenter?
Ans: Following are the various components of Informatica PowerCenter,
- PowerCenter Domain
- PowerCenter Repository
- Administration Console
- PowerCenter Client
- Repository Service
- Integration service
- Web Services Hub
- Data Analyzer
- Metadata Manager
- PowerCenter Repository Reports
Q10) What is a Mapping?
Ans: A mapping is a set of source and target definitions linked by transformation objects that define the rules for data transformation. Mappings represent the data flow between sources and targets.
Q11) What is a mapplet?
Ans: A mapplet is a reusable object that contains a set of transformations and enables to reuse of that transformation logic in multiple mappings.
Q12) What is Transformation?
Ans: A transformation is a repository object that generates, modifies, or passes data. Transformations in a mapping represent the operations the Integration Service performs on the data. Data passes through transformation ports that are linked in a mapping or mapplet.
Q13) Describe the foreign key columns in fact table and dimension table?
- The foreign keys of dimension tables are the primary keys of entity tables.
- Foreign keys of fact tables are the primary keys of dimension tables.
Q14) What is Data Mining?
Ans: Data Mining is the process of analyzing data from different perspectives and summarizing it into useful information.
Q15) What is the Fact table?
Ans: The fact table contains measurements of business processes also fact table contains the foreign keys for the dimension tables. For example, if your business process is “paper production” then “average production of paper by one machine” or “weekly production of paper” would be considered as a measurement of the business process.
Q16) What is the Dimension table?
Ans: Dimensional table contains textual attributes of measurements stored in the facts tables. A dimensional table is a collection of hierarchies, categories, and logic that can be used for a user to traverse in hierarchy nodes.
Q17) What are the Different methods of loading Dimension tables?
Ans: There are two different ways to load data in dimension tables.
- Conventional (Slow): All the constraints and keys are validated against the data before, it is loaded, this way data integrity is maintained.
- Direct (Fast): All the constraints and keys are disabled before the data is loaded. Once data is loaded, it is validated against all the constraints and keys. If data is found invalid or dirty it is not included in the index and all future processes are skipped on this data.
Q18) What are the objects that you can’t use in a mapplet?
- COBOL source definition
- Joiner transformations
- Normalizer transformations
- Non-reusable sequence generator transformations.
- Pre or post session stored procedures
- Target definitions
- Power mart 3.5 styles Look Up functions
- XML source definitions
- IBM MQ source definitions
Q19) What are the different ways to migrate from one environment to another in Informatica?
- We can export repository and import into the new environment
- We can use Informatica deployment groups
- We can Copy folders/objects
- We can Export each mapping to xml and import in a new environment
Q20) What is the difference between the mapping parameter and variable?
- A Mapping parameter is a static value that you define before running the session and its value remains until the end of the session. when we run the session PowerCenter evaluates the value from the parameter and retains the same value throughout the session. When the session runs again it reads from the file for its value.
- A Mapping variable is dynamic or changes anytime during the session. PowerCenter reads the initial value of the variable before the start of the session and changes its value by using variable functions and before ending the session its saves the current value (last value held by the variable). The next time when the session runs the variable value is the last saved value in the previous session.
Q21) How to delete duplicate records in Informatica?
Ans: Following are ways to remove duplicate records
- In source, qualifier use select distinctly
- Use Aggregator and group by all fields
- Override SQL query in Source qualifier
Q22) What are the different types of repositories that can be created using Informatica Repository Manager?
- Standalone Repository: A repository that functions individually and is unrelated to any other repositories.
- Global Repository: This is a centralized repository in a domain. This repository can contain shared objects across the repositories in a domain. The objects are shared through global shortcuts.
- Local Repository: Local repository is within a domain. A local repository can connect to a global repository using global shortcuts and can use objects in it’s shared folders.
Q23) How to find all invalid mappings in a folder?
Ans: Use the following query
SELECT MAPPING_NAME FROM REP_ALL_MAPPINGS WHERE
SUBJECT_AREA='YOUR_FOLDER_NAME' AND PARENT_MAPPING_IS_VALIED <>1
Q24) What are the data movement modes in Informatica?
Ans: Data movement modes determine how the power center server handles the character data. We choose the data movement in the informatica server configuration settings. Two types of data movement modes available in Informatica.
- ASCII mode
- Unicode mode
Q25) What is OLTP?
Ans: OLTP is an abbreviation of On-Line Transaction Processing. This system is an application that modifies data the instance it receives and has a large number of concurrent users.
Q26) What is OLAP?
Ans: OLAP is the abbreviation of Online Analytical Processing. This system is an application that collects, manages, processes, and presents multidimensional data for analysis and management purposes.