Data Deduplication

Data Deduplication is mostly involved in ETL or ELT process.

‘Data Deduplication is about removing duplication in the data.’

There are two kinds of data which can be duplicated i.e., 1) Raw or Processed Data and 2) Absence of Golden Record

Types

1. Raw or Processed Data: With-in this type of data, there are many ways to have duplicate data but below are two main reasons why mostly it ended up generating duplicated data.
   1. Data entered from front-end applications like when system is so badly designed that it allows to enter duplicate data e.g., a customer is wrongly created twice, or a product sold once but system allows to enter it more than one time as human error. This data must be removed as part of the Data Quality process.
   2. Data transformed during ETL/ ELT process from source systems to Data Warehouse or Data Marts or Semantic Layers etc. This data also needs to be removed by Data Quality process.
2. Absence of Golden Record: Duplicates also occur when golden records are missing? What is Golden Record? Absence of Golden Records means, when there is more than one code for single entity e.g., consider an insurance company has a SAME TYPE OF POLICY with policy code as 001 in one system and 002 in second system and 003 in third system, now when data from all these three systems flows into a centralized location which can be a Data Warehouse or a Data Mart there will be transactions related to each of these policies but in reality all belong to SAME TYPE OF POLICY. When this data goes to the marketing department and they plan to send online campaigns, instead of sending 1 campaign for 1 type of policy, there will 3 campaigns designed for the same 1 type of policy. This scenario can be handled by a de-duplicated Golden Record with the help of Master Data Management (MDM) Application.