Application Testing - Oracle to SQL Server Migration

Application Testing Methodology and Process

When you migrate Oracle databases to SQL Server, in most cases you also have to convert embedded SQL statements in your applications written in Java, .NET, PowerBuilder, C/C++ or other languages.

Application testing is one of the most important phases of a migration project, and usually several testing approaches are applied to increase the testing coverage and quality:

• Code Review
• SQL Statements Testing
• User Acceptance Testing (UAT)

If you think that your application is very simple, and no testing required, see how even the simplest functions Oracle LENGTH and SQL Server LEN that return the length of a string behave differently.

Migration testing is typically focused on the following areas:

• SQL Testing

SQL Testing is used to make sure that the original Oracle and the converted SQL Server SQL statements bring the same results.

• Performance Testing

Performance Testing is used to measure the execution time of Oracle and SQL Server queries, insert, update and delete statements.

Your application can contain a huge number of SQL queries that range from very simple to very complex. Some of them even do not require conversion at all, while others have to be completely rewritten when you migrate from Oracle to SQL Server.

It is critical to identify the most challenging SQL statements during the assessment, development or code review phase, and develop sophisticated routines for further testing of such statements using a large number of test cases with various input data.

Code Review is performed by a migration architect or expert to see whether the migration guidelines and best practices defined at the Design and Planning Phase are actually implemented.

If you did not perform a comprehensive migration design, an experienced migration architect can validate the migration solutions you applied, and point to potential issues.

SQL Statements Testing is usually performed by SQL developers who test the converted statements for syntax errors, and compare the results between Oracle and SQL Server on the sample data.

Typically SQL statements are manually extracted from the application and executed in a query tool as standalone queries without following any application workflow.

Besides SQL statements, the stored procedures and user-defined functions are also tested by executing with a test input and comparing the results.

User Acceptance Testing usually involves running the migrated database and applications, following various application use cases, and visually comparing the results that appear on the screens, in the reports etc.

SQLines offers services to help you test database and application migrations from Oracle to Microsoft SQL Server. For more information, please Contact Us.