Data migration is the process of moving data between storage units or entire computer systems. In order for this process to be efficient, powerful data extraction and data loading designs are critical. These designs help in mapping data, which is present on the current system, to the new system which is being implemented. One of the categories of Data migration is Database Migration. Database migration is the process of moving the business logic, schema, physical data and database dependencies from a current system to a different/new system. Database Migration is used when it is required to shift from one database vendor to another. This may be because of various reasons such as cost, capabilities, functionalities, requirements etc.
Typically data migration occurs during an upgrade of existing hardware or transfer to a completely new system. Examples include: migration to or from hardware platform; upgrading a database or migrating to new software; or company-mergers when the parallel systems in the two companies need to be merged into one. There are three main options to accomplish data migration:
- Merge the systems from the two companies into a brand new one
- Migrate one of the systems to the other one.
- Leave the systems as they are but create a common view on top of them – a data warehouse.
A high amount of data is being managed by databases and applications in companies today. In many cases data is extracted from several different databases, then managed and finally stored in yet another database. The process of moving data from one database to another is called data migration. The data migration process can eventuate in several new problems, especially considering the high amounts of data that is being processed.
The data migration process can be performed manually, but it is very time consuming to do that, so most often it is automated, through different software products or by hiring an data migration company. In order to achieve an effective data migration, a transformation of the data on the old system may be required in order for the data to conform to the new system design. This is often done by developing a design that matches the old data to the new database’s format and requirements.
Database are growing very fast and becoming more complex in the volume (terabyte to petabyte), variety (structured, unstructured and hybrid), and velocity (high speed in growth). Management of database has become the global challenge. The data collection is currently managed and exploited mostly by using conventional data management tools such as classic relational database management systems (RDBMS) or conventional search engines. Figure 1 depict the architecture of database migration.
Figure 1: Database Migration Architecture
Database migration is the process of moving the business logic, schema, physical data and database dependencies from a current system to a different/new system. Database Migration is used when it is required to shift from one database vendor to another. This may be because of various reasons such as cost, capabilities, functionalities, requirements etc. Database independent applications necessarily shoot for the lowest common denominator of all of your database platforms, thus lowering the bar on what high-performance features you might take advantage of on the platform you are currently using.
Characteristics of Database Migration
On first thought, it may seem that when two systems have to hold similar data they would relate to one another seamlessly. But this is most certainly not the case. The differences in their architectures, technology and implementation lead to innumerable issues during database migration. For this reason, database migration projects (and hence data migration projects) have a tendency to fail.
- Schema Migration- Replicating the database schema of the current system in the new system
- Data Migration- Extraction of data from the current system and loading it on to the new system
- Application Migration- Making necessary changes in the applications associated with the current system so that its behavior remains unchanged when made to interact with the new system
 Arun Swaminathan, “Database Migration- How hard can it be?” 2nd International Conference on Information Communication and Management (ICICM 2012), Volume 55, IACSIT Press, Singapore
 “Data Migration”, Data Integration Info: Quick view on world of data, available online at: http://www.dataintegration.info/data-migration
 Rintamäki, Lina, “Data migration, a practical example from the business world”, Master of Science Thesis in Software Engineering and Technology, August, 2010.
 Anil Mahadev, “Database Migration: An in Depth look!!” available online at: https://db2hitman.files.wordpress.com/2010/03/database-migration-word.pdf