Database migration is the process where data from one or more source databases is migrated to one or more target databases via a database migration service. When the migration is completed, the source data resides fully in the target database, sometimes as restructured data. Users working on the source databases are transferred to the target databases and the source is turned down.

Reason for Oracle to SQL Server migration

The main reason is that organizations are always looking to save and cut down on technology costs. One of the optimized methods to achieve this goal is to adopt economical technologies and software that assure the same results without compromising on the speed or quality of database functioning. You can move your dBase data to MS Access, and create Microsoft access dbase files with a modern look. In the modern data-driven business environment, enterprises have to spend substantial amounts on license and support fees, not to forget the expenses on trained staff to maintain these databases. In this regard, when compared to the Oracle database, Microsoft SQL Server is a more economical option, a great incentive for organizations to opt for Oracle to SQL Server migration.

Differences between Oracle and SQL Server

Before going to the core process of Oracle to SQL Server migration, it is essential to understand the differences between the two databases. Some features give Oracle the edge over SQL Server and vice versa.

  • Microsoft SQL Server can be installed on Windows Server only while Oracle database can be operated on several platforms.
  • SQL Server provides schemas within each database only while Oracle database supports several schemas with an instance.
  • Values may be changed before commit in SQL Server while it cannot be changed in the Oracle database.
  • Star query optimization is not supported by SQL Server while the facility is offered by the Oracle database.
  • Full, incremental, and partial backups are provided by SQL Server while Oracle database offers full, incremental, and differential backups.

From these features, it is possible to understand the several advantages of Oracle to SQL Server migration

Benefits of Oracle to SQL Server migration

Several benefits accrue to businesses going through this migration process.

  • Cost-effective: As discussed, SQL server is a more cost-effective option over Oracle database. Businesses have to pay more for using Oracle Enterprise Manager or Oracle Data Guard than similar features offered by SQL Server. For example, advanced features of SQL database engines like Analysis Services or Reporting Services are included under a single license cost. Further, users of SQL Server databases can monitor costs and keep them under control by optimally allocating resources, merging databases, compressing data, and visualizing servers, all of which results in streamlined database management.
  • Handling data volumes: Comparatively, SQL Server is more adept at handling massive data volumes for processing loads and running applications than Oracle database.
  • License fees: Businesses that use the Oracle database are locked into this vendor even though the license fees are high. This becomes more apparent when the existing infrastructure and systems are upgraded or modernized as it comes with highly increased license fees. Microsoft SQL Server, on the other hand, provides users with the required scale and performance to upgrade at limited charges.
  • Reporting systems: One of the rewards of Oracle to SQL Server migration is that it allows exclusive designing of reporting systems. This is done through its automated business intelligence capabilities, thereby doing away with the dependence on database administrators.

All these cutting-edge features are a motive for enterprises to go for Oracle to SQL Server migration.

Initial steps before Oracle to SQL Server migration

Before the migration process is started, a few preliminary steps have to be taken for preparing the groundwork.

  • SQL Server has to be installed on the target database and proper connection and accessibility have to be ensured between the source Oracle and target SQL Server.
  • Oracle Client and SQL Server Migration Assistance (SSMA) have to be installed on that server.
  • SSMA has to be launched and connected to the source Oracle database and ensured that connectivity to the port and firewall issues have been taken care of.
  • Connect to the SQL Server at the target that has been installed in the first step.
  • Oracle schema that has to be migrated to the SQL Server database is to be mapped.
  • All Oracle objects have to be converted and loaded to the SQL Server.
  • This loaded data has to be migrated to the target database.

Once these fundamental processes are completed, the migration proper can be started.

Types of Oracle to SQL Server migration

There are two types of migration processes.

  • Single-phase method: All systems have to be shut down and the migration is started and completed in one go. If not, any transaction that has been done in the source database after the last backup will not be reflected in the target database. Before the actual process, it is advisable to carry out test executions to avoid any glitches during migration.
  • Two-phase method: First, complete migration is carried out between the source and the target databases. Once this is done, preset timers are activated to carry out continual loading of data between the source and the target ensuring uninterrupted capture of incremental data after the last run.

The method chosen for Oracle to SQL Server migration depends on the convenience of the organization.