MDM Interview Questions

MDM is a methodology of allowing an organization to link all of its important data to one file, which is called a master file. This file provides a common base of reference. When implemented properly, MDM networks data sharing among individuals and enterprise.

People associated with IT and Computers get the concept easily. Business official understands MDM but not up to the level of former because businessmen are more interested in only knowing what benefit MDM can bring to their group. While IT and Computer people, know more about the features of MDM.

Dimensional Modelling has two types of tables which is distinct from the third normal form. Here, Facts table containing the measurements of the business and Dimension table containing the context viz. dimension of calculation of the measurements are implemented.

Management’s decision support system is served with the raw source by the Data Warehouses. The use of Data warehouse becomes essential because a Data Analyst can perform complex queries and analysis like data mining which makes use of a data warehouse. At a single point in time, we are able to present a clear image of business conditions with the help of Data warehousing which otherwise contains a wide variety of data.

Four fundamental stages of Data Warehousing are Offline Operational Databases, Offline Data Warehouse, Real-Time Data Warehouse, and Integrated Data Warehouse.

• Development of Data warehouses in Offline Operational Databases is done by copying the database of an operational system to an off-line server.
• Data warehouses in Offline Data Warehouse are updated regularly and their storage is done in an integrated reporting-oriented data structure.
• Every time an operational system carries out a transaction, data warehouses are updated on an event basis in Real-Time Data Warehouse.
• Data warehouses are used to generate activity or transactions In the Integrated Data Warehouse, that is sent back into the operational systems to use in the daily activity of the enterprise.

PowerCenter is the data integration software of Informatica Corporation. The usage of this software allows loading the data into centralized locations such as data warehouses. Data taken from multiple sources can be used as per the business requirements.

The components of Informatica PowerCenter are written below:

• PowerCenter Domain
• PowerCenter Repository
• Administration Console
• PowerCenter Client
• Repository Service
• Integration service
• Web Services Hub
• Data Analyzer
• Metadata Manager
• PowerCenter Repository Reports.

Conference of MDM was hosted by Gartner for the first time and they managed to pull five hundred attendees in the conference.

It is very necessary to host such conferences. For example, the budgets of the Pharmaceutical and Financial services industries are increasing. By 2010, Forrester predicted MDM to be a $6 billion market which was a sixty percent growth rate over the $1 billion MDM market in the previous year. Gartner also forecasted that seventy percent of two thousand global companies will have an MDM solution, by the year 2010.

The primary issue is Funding while selling the project is a secondary issue. The management is actively looking for an investment return. They want MDM to be benefitting and profitable for their business.

Mapping represents the flow of data between targets and sources. A mapping is a set of target definitions and source linked by objects of transformation which define the data transformation rules.

A Mapplet is a reusable object containing a set of transformations. It enables to reuse that transformation logic in multiple mappings.

A transformation is an object that generates, modifies or passes data. So, it is a repository object. Transformations in a mapping represent the operations the Integration Service performs certain operations on the data in a mapping that are represented. Transformation ports are linked in a mapping or mapplet and the data passes through these ports.

The primary keys of entity tables are called foreign keys of dimension tables.

The primary keys of dimension tables are foreign keys of facts tables.

Data Mining is the process of analyzing data from different perspectives and summarizing it into useful information.

The measurements of business processes are present in the fact table. The foreign keys for the dimension tables are also contained by the facts table. For instance, in the “tea production” business, the “average tea production tea by one machine” or “weekly tea production” would be considered as a measurement of the business process. Whereas textual attributes of measurements stored in the facts tables are included in the dimensional table. A dimensional table is a cumulation of categories, hierarchies, and logic.

The two ways of loading a Dimensional Table are written below:

• The first is a Conventional (Slow) method – Before the data gets loaded, all the keys and constraints are validated against it. Data integrity is maintained this way.
• The second is a Direct (Fast) way – Before the data gets loaded, all the constraints and keys are disabled. Data is validated against all the constraints and keys once it is loaded.

The folder/objects can be copied by us. The repository can also be exported and imported into the new environment. We can also export each mapping to XML and import in a new environment. Informatica deployment groups can also be used.

OLTP is an application that modifies data the instance it receives and has a large number of concurrent users. While OLAP is an application that collects, manages, processes and presents multidimensional data for analysis and management purposes.

There are three ways to delete duplicate record in Informatica:

• In source, qualifier use selects distinctly.
• Override SQL query in Source qualifier.
• Use Aggregator and group by all fields.

A Mapping Parameter is defined by us before running the session and its value remains until the end of the session which makes it a static value. Whereas a Mapping Variable changes anytime during the session and that is why it is dynamic. The initial value of the variable is read by the PowerCenter before the session starts and its value changes using the variable functions.