Database is a must for every system. Information (about user or transaction state) is usually maintained in traditional relational databases such as MySQL and Oracle.
SQL is a standard computer language for relational database management and data processing. It allows to query, insert, update and modify data. You can think of SQL as a means of communication between the user and the DBMS (Database Management System).
Simply put, SQL is the programming language which helps to access our database.
To define an SQL query, we first need to understand what is a query. A query can be defined as a request for data from a database via a DBMS. A query can be thought of as an instruction sent to the DBMS to retrieve a dataset based on criteria. Such a query can be developed using SQL and is called an SQL query.
A simple SQL query would be: Select * from Table.
By looking at this query, you can easily understand what does it do — selects all the data (represented by *) from the table.
When you do functional testing of the system through the frontend (website, mobile apps, etc.), you also need to check if the data you are sending is being updated correctly in the database.
The demand for universal testers is growing. This means that testers must be proficient in testing the functionality of a system using traditional testing methods (point-click-and-test) and be able to use technical knowledge to test all aspects of the system. This knowledge includes skills about validation of operating system, interface and database. In this case, we emphasize the importance of good skills in Structured Query Language (SQL).
Some applications require strong SQL validation skills, some require intermediate skills, and others require no SQL knowledge at all.
Take, for example, websites that host documents that users can send to a printer. Printing these documents requires users to first install a dedicated print controller on their PC. Testing their print quality, in this context, involves printing documents from combinations of various operating systems, browsers and printers. You don’t need to apply any SQL skills for this test. SQL experience is required to validate test data, insert, update and delete test data values in the database.
Let’s take a look at another project — participating in backend testing which requires a strong knowledge of SQL queries. Internal user interface tool for retrieving data from an Oracle database based on input values. Testing compares the output of the user interface tool and the output of the database, and enters the same values into the tool and the database to ensure that the tool is functioning as expected. Each time the input values change, the database administrator uses a select statement to issue very large queries to the test team. First, you need to understand the relationship between tables, columns and a query before using it. In addition, you need to use different types of SQL statements to validate the test data.
A tester must have the following knowledge of the database and SQL:
Most used SQL statements in testing:
SQL is very important in software testing because:
Given the benefits of working with SQL and the usefulness of SQL skills in general, our advice to testers is — in order to become a versatile tester that is appreciated by customers and companies, you should acquire a minimal knowledge of SQL.