What is Data Migration (DM)?
Data Migration refers to the transfer of data from one or more software application / system to another or from one type of technology to another. Migration here literally means movement – from one file or database or system / application to another corresponding one.
The process basically includes three main operations ETL – Extracting, Transforming & Loading of Data, supported by other complementary procedures.
Migration cannot be carried out over night. It requires careful planning and designing to map the data from the old system to the new one. Avoiding loss of data is of primary importance while designing.
Extracting of Data
This involves pulling out necessary data from source application(s) / system(s) that should be migrated to another application or system.
Cleansing & Transforming
Not all data from source might be required in the target application or system; not all data to be migrated are in the needed formats, types etc. This requires data to be standardized, segregated, and transformed into the formats as required in the target application or system.
Example: Date of Birth in source system is written as 7th Feb 1960 while target system needs it as 07/02/1960. Changing the date format is also transformation.
All the transformed data has to be loaded into a consolidated form in the target application / system.
Testing for accuracy
The loaded data has then got to be checked for accuracy - to check if all data has been transferred and functioning well to support operations in the new system. At times both systems are run simultaneously. This is to avoid discrepancies and erroneous loss of data, during the ETL operations which would affect the enterprise in a huge way.