Writing SQL queries
To test the database correctly and accurately the top testing companies recommend testers, first of all, to learn properly SQL and DML (Data Manipulation Language). Second of all, a tester must splendidly understand the database internal structure. If these two conditions are met, the employee is ready for the database testing. He or she will perform any CRUD operations from the Application UI, and then will verify the results of performing by means of SQL-queries.
It is the best and the most reliable way of database testing especially for applications of low and middle level of complexity. But the two described preconditions are obligatory – otherwise this manner of the database testing is futile.
If the application is very complex, then it will be very difficult or even impossible for a tester to write all the necessary SQL-queries by him- or herself. Therefore, in the case of some complex queries a tester can appeal to developer for a help.
This approach not only provides the confidence that the testing is qualitative, but also enhances the skills of writing SQL-queries.
Viewing data in tables
If a tester does not know SQL, than he/she can check the result of the CRUD operations performing by means of application’s GUI viewing the tables (relations) of the database. This method of the database testing requires a good knowledge of the tables’ structure, besides it can be a little bit tiresome and bulky, especially when the database and tables have a large data scope.
In addition, this technique of the database testing can be very difficult for testers, if the data to be tested are spread among multiple tables.
This is the simplest way. A tester performs any CRUD operations with a graphical interface and checks their results performing the relevant SQL-queries written by developer. Many testing service providers maintain that this method does not require a good knowledge of SQL or the structure of the application’s database.
Thus, this process seems to be simple and is a good choice for database testing. But its drawback is chaos. What should be done if the query written by developer is semantically incorrect or if it does not correctly meet the user requirements? In this case testing does not assure any guarantees about the product’s quality.
The database is a primary and the most important part of almost every application. So, among many other testing software services, a professional should not forget about improving his/her skills on the database testing. It requires close attention, mastership in writing SQL-queries, satisfactory knowledge of the database structure and the corresponding training.