10/23/12

Difference Between Master Data Management(MDM) and Data warehouse

Master Data Management and Data Warehousing have a lot in common. For example, the effort of data transformation and cleansing is very similar to an ETL process in data warehousing, and in fact they can use the same ETL tools. In the real world, it is not uncommon to see MDM and data warehousing fall into the same project. On the other hand, it is important to call out the main differences between the two:


1) Different Goals

The main purpose of a data warehouse is to analyze data in a multidimensional fashion, while the main purpose of MDM is to create and maintain a single source of truth for a particular dimension within the organization. In addition, MDM requires solving the root cause of the inconsistent metadata, because master data needs to be propagated back to the source system in some way. In data warehousing, solving the root cause is not always needed, as it may be enough just to have a consistent view at the data warehousing level rather than having to ensure consistency at the data source level.


2) Different Types of Data

Master Data Management is only applied to entities and not transactional data, while a data warehouse includes data that are both transactional and non-transactional in nature. The easiest way to think about this is that MDM only affects data that exists in dimensional tables and not in fact tables, while in a data warehousing environment includes both dimensional tables and fact tables.


3) Different Reporting Needs

In data warehousing, it is important to deliver to end users the proper types of reports using the proper type of reporting tool to facilitate analysis. In MDM, the reporting needs are very different -- it is far more important to be able to provide reports on data governance, data quality, and compliance, rather than reports based on analytical needs.


4) Where Data Is Used

In a data warehouse, usually the only usage of this "single source of truth" is for applications that access the data warehouse directly, or applications that access systems that source their data straight from the data warehouse. Most of the time, the original data sources are not affected. In master data management, on the other hand, we often need to have a strategy to get a copy of the master data back to the source system. This poses challenges that do not exist in a data warehousing environment. For example, how do we sync the data back with the original source? Once a day? Once an hour? How do we handle cases where the data was modified as it went through the cleansing process? And how much modification do we need make do to the source system so it can use the master data? These questions represent some of the challenges MDM faces. Unfortunately, there is no easy answer to those questions, as the solution depends on a variety of factors specific to the organization, such as how many source systems there are, how easy / costly it is to modify the source system, and even how internal politics play out.



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