Test-Taker Experience on our Database Query Simulator

Test-Taker Experience on our Database Query Environment

The interface of Mercer | Mettl's database query environment (DBLysis) includes many key components such as a query editor for writing and editing queries, a database engine for executing the queries, test cases for evaluating the query's functionality, an output window to view the output of the query compilation and various other features which make it easier for the test takers to adapt to the interface and focus on solving the problem statement at hand.

This article aims to give the test taker a look and feel of the simulator and resolve any queries they might have with respect to the user interface. 


This section gives a guided tour to the test taker on how to use the platform. 

It starts automatically as soon as a database query writing question appears, and test-takers can revisit it anytime by clicking on the How to attempt button on the left side of the page, above the problem statement. 

Problem Statement  

The problem statement contains specific instructions on the desired output and how to obtain it by writing question specific queries.  

Query Editor 

In the query writing section of the simulator, test takers are provided with a designated area where they can write, edit and test their query to the database question. The test-takers have the option to switch the editor to full screen by clicking on the arrow beside Enter your response above the editor.

Note: Test takers can execute only DQL queries in the query editor.  

Database Variants Available

The simulator supports six database variants which they can select from the dropdown above the editor. As of today, the database variants supported on the simulator are MSSQL 2016, MYSQL 5.7, MYSQL 8.0, Oracle 19C, POSTGRES 14.7 and MARIADB 10.6.  
This provides flexibility to the test-takers as they can choose a variant, they are comfortable with and switch to any of the available variants in the middle of the assessment, as many times as they want to.  

View Schema 

The test-taker has the option to view the schema by clicking on the View Schema button below the query editor. They also have the option to zoom in and out of the schema and have a proper look according to their convenience.  

Run your Query 

After a test-taker is done writing the queries, the next step is to click on the Run Query button which will take them to the Output tab, execute the queries and show them the output of their queries. 

Submit your Query 

By clicking the Check Query button, the test-taker can submit their query to the problem statement and the output of their query is checked against the testcases in the backend and the status of the same is then visible on the Test Cases Tab.  

In case of any mismatch in the output of the candidate‚Äôs query and the answer query, the error gets displayed to the test-taker with the status as FAILED.  
Every testcase holds a grade which will be awarded to the test-taker only if it passes. The test taker has the option to edit their queries and execute it as many times they wish and finally submit their final query.