Database Testing Interview Questions

Database testing is concerned with ensuring the integrity, correctness, and accuracy of data held in databases. It helps organizations manage risks connected with erroneous data in data sources by preventing data loss, defining the behaviour of a system in the event of failed transactions, and so on. Here are the top 40 Database Testing interview questions, along with detailed answers.

We have categorized Database Testing Interview Questions - 2023 (Updated) into 2 levels they are:

• Freshers
• Experienced

Frequently Asked Database Testing Interview Questions

1. What is Database Testing?
2. What is Database Stress Testing?
3. Why is SQL used in testing?
4. How does QTP evaluate test results?
5. How can you validate the ACID properties? Explain with an example.
6. How is stored procedure testing done?
7. What is structural database testing?
8. How do you test the database triggers and procedures?
9. How will you perform data load testing?
10. What are the differences between GUI Testing and Database Testing?

If you want to enrich your career and become a professional in SQL Server, then enroll in "SQL Server Training". This course will help you to achieve excellence in this domain.

Database Testing Interview Questions For Freshers

For freshers, here are some often questioned Database Testing Interview Questions.

1. What is Database Testing?

Database testing involves examining data in a database, as well as the functionality and objects that control database entities including tables, stored procedures, views, triggers, and functions. In database-based systems, this kind of testing is prevalent. As a result of modern technologies and advancements in software development, databases are widely used to store data, which necessitates the verification of data quality and correctness. It's divided into four parts:

1. Data Validity Testing: In order to retrieve and validate data from the database, this sort of testing necessitates familiarity with SQL queries.
2. Data Integrity Testing: During data integrity testing, testers must evaluate data against imposed limitations and database integrity requirements.
3. Database Performance Testing: In this case, the testers must validate the performance of various triggers, indices, and processes in order to determine how efficiently the activities are carried out. The system must also be able to efficiently perform database transactions. While doing this, you'll need to have a good understanding of database structures.
4. Validating the logic linked with triggers, functions, and procedures found in the database.

2. What do you know about data-driven testing?

Data-driven testing is an automated testing framework that involves using data contained in a spreadsheet or table as input values to test scripts. This is done to prevent creating individual test cases with various inputs for the same functionalities. The test scripts' inputs might be in XML, CSV, XLS, and some other data formats.

Based on the source of test data inputs, there are four basic forms of data-driven testing:

• Key-driven: When using a keyboard to retest the application and evaluate the business logic, dynamic data is presented as inputs to the test cases.
• Flat files: Input data contained in flat files such as.doc or.txt is used to retest applications.
• Front-end objects such as a list, table, menu, or data window are used in the test scripts.
• Spreadsheet/Excel: In this case, the test data is taken from excel sheets or spreadsheets.

3. What is retesting & how it is different from data-driven testing?

The re-execution of the same test with different input values to ensure the original flaw has been effectively removed is termed Re-testing or confirmation Testing after the test has been completed in terms of identifying the defect that has already been recognized and rectified.

After earlier testing, retesting entails running the same test with different input values, identifying the fault, and correcting it. Retesting varies from data-driven testing in that it is a manual process in which the application is tested with a new data set, whereas data-driven testing is an automated process in which the application is tested with several sets of test data.

4. What is Database Stress Testing?

Database Stress Testing is one of the approaches for evaluating database performance by putting it under a significant load that could cause the system to fail. This is used to figure out where the database application's breakdown points are. To avoid wasting resources, appropriate planning must be carried out prior to undertaking this testing. Fatigue testing is another name for this type of analysis. It accomplishes this by utilizing tools such as LoadRunner and JMeter.

5. What do you know about database transactions?

A database transaction is a job sequence that must be done on the database to logically attain the desired outcomes. Creating, removing, and updating records in database tables are examples of tasks. When tasks are completed successfully, they have an impact on the database entries. A transaction includes four controls, which are listed below:

• Commit: This is used to save all transaction modifications. This is where we put our Insert, Update, and Delete statements.
• RollBack: This is used to revert the transaction to the state it was in before it was operated. This is where we put our Insert, Update, and Delete statements.
• Savepoint: This specifies the point at which the transaction should be rolled back.
• Set Transaction: This command is used to change the transaction's name.

6. What do you mean by Non-functional testing in terms of database testing?

In terms of database testing, non-functional testing entails a variety of testing methods such as stress testing, load testing, usability testing, security testing, and others that test and validate non-functional business requirements. It aids in the quantification of database system risks in terms of how the system works under high demand.

It answers the following questions, which can help to mitigate risks if they are recognised early:

• Is there a malfunction with the system?
• Is there a lag in the system?
• Is the system at risk when the load or stress on it grows?
• Is the system scalable and adaptable to changing company needs?

Non-functional testing also aids in determining the basic requirements for a system to perform properly without any hardware or software limitations.

7. What is load testing and give some examples of it?

Load testing is a technique for determining how well a system works. When a load exceeds a user's pattern, stress testing is carried out. Load testing involves downloading a large number of files, running multiple apps on a single computer, sending a large number of emails to a server, and assigning multiple tasks to a printer one by one.

8. What is SQL?

SQL is the most widely used language for retrieving and organizing data from relational databases. A table with rows and columns is called a database. Databases are written in SQL. It makes it easier to extract specific data from databases, which can then be analyzed.

[ Related Article: SQL Server Tutorial ]

9. What is the way of writing test cases for database testing?

Writing test cases is related to functional testing. To begin, you must first comprehend the app's functional requirements. Then you must decide on the test case parameters, which include things like

• Objective: Make a list of the objectives you want to test.
• Method of input: Write the action or input method you want to use.
• Expected: How it should show in the database is what is expected.

10. Why is SQL used in testing?

SQL unit testing is a type of testing that allows us to test the tiniest, programmable portion of a database entity. Because it allows us to test specific components of database objects to see if they perform as expected, SQL unit testing is an important part of the current database development cycle.

11. What is the QTP testing process?

The following steps make up the QTP testing procedure:

1. Creating GUI (Graphical User Interface) Map files: This step identifies the GUI object that needs to be tested.
2. Creating test scripts: Test scripts are written on paper and then played back.
3. Debug tests: It's important to debug your tests.
4. Test Cases must be executed.
5. Examine the outcomes: The outcomes show whether the tests were successful or unsuccessful.
6. If the test fails, the reasons will be documented in the report to detect the file.

12. How does QTP evaluate test results?

When the testing is finished, QTP will prepare a report. This report will show the test results, including checkpoints, system alerts, and failures. The test results box will indicate any mismatches discovered at the checkpoints.

13. What would be the SQL statements used for managing and manipulating the test tables?

For altering table content, we can utilize commands like Insert, Update, Select, and Delete. Alter Table, Delete Table, and Create Table are the table statements used to create and manage tables.

14. What do you understand by validation of ACID properties in database testing?

Atomicity, Consistency, Isolation, and Durability are the four characteristics of  an ACID. The term "everything" refers to a transaction property in a database.

• Atomicity - This refers to the fact that transactions are atomic, meaning that the outcome of a transaction may only be a success or a failure, with no between ground.
• Consistency - This feature suggests that the database's state must remain valid after the transactions are completed.
• Isolation - This refers to the fact that several transactions do not interfere with one another or the database's state.
• Durability - This specifies that data should not be lost after a transaction has been committed, even if there is a power outage.

15. How can you validate the ACID properties? Explain with an example.

Take a look at the following SQL code:

CREATE TABLE ACID_DEMO (X INTEGER, Y INTEGER, CHECK (X + Y = 50));

For two columns, X and Y, we'll check for ACID characteristics. On the table, there is also a constraint that the sum of the values in columns X and Y must always equal 50.

• Atomicity: This is where we check whether the table operations were successful or unsuccessful. If a transaction fails, no records should be changed.
• Consistency: The values in columns X and Y are updated correctly by obeying the restriction that the sum of these two values is always 50. If the sum does not equal 50, no insertion or updating should be permitted.
• Isolation: In the case of several transactions, we must ensure that each one is carried out independently.
• Durability: The test cases should take into account that once a transaction has been committed, it should be committed even if there are power outages, crashes, or errors. If we're going to use shared or distributed database apps, we'll need to do a lot of testing to make sure the data isn't lost.

16. How can you write test cases from requirements and do the requirements represent the exact functionality of AUT (Application Under Test)?

To write test cases from requirements, you must first conduct a thorough functional analysis of them. Then you evaluate suitable test case design methodologies for building the test cases, such as equivalence partitioning, black box design, cause-effect graphing, and so on. Yes, the specifications detail the AUT's capabilities in great detail.

17. Explain with an example how you can test the database manually?

Manual database testing is also a possibility. This necessitates human effort in observing the application's behavior as it is subjected to various manual test cases written by the testers. This can also include seeing how front-end applications behave after the backend database has been altered. Following the execution of the queries, we can manually check whether a record was created, changed, or destroyed in the database tables.

Consider a database system for student information. The activities performed on the Student tables database can be manually verified by seeing the status of the records after the query has been executed, or by inspecting the front end interface.

[ Learn Complete Manual Testing Tutorial ]

18. In database testing, what all things are required for writing good test cases?

Before writing database test cases, you must have the following knowledge. ,

• Understand the application completely, as well as the program's functional requirements.
• For generating that need, look at other entities that have been utilized in an application, such as back-end database tables, joins between the databases, cursors (if any), triggers (if any), stored procedures (if any), input parameter and output parameter.
• After gathering all necessary data, create a test case with various input values to examine all of the resources.
• Writing test cases for back-end testing is the polar opposite of functional testing, and white box testing should be used instead.

19. How do you validate whether the database table has been updated after you enter data from the front-end application?

This is determined by the user interface of the front-end program. The following methods can be used to conduct tests:

• In the front-end application's display, look for any changed data. After the new value is successfully inserted, the view must be updated with it. Black box testing is what this type of testing is referred to as.
• If no view is accessible, we can go to the database system, execute a select query, and manually check for data.
• For checking database updates, we can also utilize WinRunner or QTP.

20. How is stored procedure testing done?

Cal Procedure and Execute Procedure statements are used to call stored procedures, which are comparable to user-defined functions. Result sets are the most common outcome of these operations. The stored procedures are kept in a relational database management system (RDBMS) and are easily accessible to the applications. 

The following procedures can be used to test these:

• White box testing: White box testing (WBT) is a type of software testing that examines the internal structure of a program. It is also called Code-Based Testing (CBT) or Structural Testing. To design test cases and the internal structure of an application in white-box testing, the tester needs to have a thorough understanding of the application's internal structure as well as good programming abilities.

• Black box testing:  Black box testing is a software testing method that allows you to examine an application's functional functionality without having to look at its internal structures. Black-box testing does not necessitate knowledge of the core application's code/internal structure or programming, but it does necessitate an understanding of the application's functioning.

21. What are the different SQL statements that can be used for database testing?

In database testing, you can utilize all SQL DDL, DML, DCL, and TCL statements.

1. DDL (Data Definition Language): This language includes all statements that can be used to define the database structure or schema.

CREATE, ALTER, DROP, TRUNCATE, COMMENT, and RENAME are statements that can be used in a programme.

2. DML (Data Manipulation Language): This language's statements can all be used to manage data within schema objects.

SELECT, INSERT, UPDATE, DELETE, MERGE, CALL, EXPLAIN PLAN, and LOCK TABLE are some of the statements available.

GRANT and REVOKE statements in DCL (Data Control Language).

3. TCL (Transaction Control Language): All TCL statements can be used to handle DML modifications. TCL allows you to create logical transactions by grouping statements together.

COMMIT, SAVEPOINT, ROLLBACK, and SET TRANSACTION are all statements that can be used.

22. What is performance testing and what are the bottlenecks of the pit?

Performance testing is the process of determining how well a system responds to a given workload and how stable it is. Speed, robustness, dependability, and application size are often examined using performance tests.

Performance testing is used to identify performance bottlenecks that might lead to poor user experience and even program failure. Slow response times, inadequate scalability, excessively long load times, system downtime, software bugs, and other issues are the most typical system bottlenecks.

23. How to use SQL queries in QTP?

When using the output database checkpoint and database check-in QTP, select the SQL manual queries option. When choosing the custom queries option, enter the "select" queries to collect the data from the database, and then compare the projected and actual results.

24. What are joins and mention different types of joins?

A join joins two or more tables together and displays the results as a single collection of data.

The following are the several types of joins in SQL:

• Inner Join
• Outer Join
• Left Join
• Right Join.

There are four main forms of joins in Oracle/PLSQL.

• Inner Join
• Left-Outer Join
• Right-Outer Join
• Full-Outer Join.

25. What is Normalization?

In relational database design, normalization is a procedure that organizes data in order to reduce duplication. When we normalize a database, we separate it into two or more tables and link them together.

26. What is an Index and what are the different types of indexes?

Indexes are database objects that are built on the basis of columns. They are regularly accessed in order to retrieve data fast. There are various types of indexes.

• B-Tree index
• Bitmap index
• Clustered index
• Covering index
• Non-unique index
• Unique index.

Database Testing Interview Questions For Experienced

This Database Testing Interview Questions for Experienced may provide you with a better understanding of the types of questions you may be asked during a job interview.

27. Why do you think database testing is important in the field of software testing?

Database testing guarantees that data collected from multiple sources in the database is correct and meets business needs. It aids in the analysis of risks associated with wrong data, the prevention of data loss due to incorrect transactions, and the proper verification of unauthorized data access. During testing to check the accuracy of the data, the Ui is given the highest priority in most applications. However, if there isn't a user interface or a view, it's critical to check the database's data quality.

Consider a banking application with a large number of users. It is critical to keep the following points in mind while testing the database:

• Is the app storing the required transaction data and displaying it to the correct user?
• Ensure that no data is lost throughout the transaction.
• Make sure that the system does not save partially completed or aborted transactions.
• Make sure that only authorized people have access to the data.
• It is critical to have a strong understanding of data testing or database testing in order to complete these validations.

28. Write the step-by-step process to test the database?

Database testing follows the same methods as other types of testing. The procedures that are followed are as follows:

• Prepare the testing environment as well as the scripts for the tests.
• The script should be run
• Examine the results of the exam
• Compare the outcomes to what you predicted.
• The developers and stakeholders should be notified of the validation findings.

29. What is structural database testing?

This testing entails examining database structures such as schema, tables, triggers, functions, and procedures, as well as the databases' servers. The types of structural testing are as follows:

1. Schema Testing: The precise schema name should map between the front-end and the back-end in this case. Because the schema of the tables may differ from the actual business requirement and the front-end applications in some circumstances, schema validation is highly significant. Unmapped tables, views, and columns must also be verified.

2. Tables Testing: This testing entails checking the names of tables as well as the columns within them. The names of the columns mapped to the frontend and backend should be the same, and the datatype and widths of the columns should match the business needs. It also entails putting table and column limitations to the test. Furthermore, indexes should be checked based on whether they are clustered or non-clustered, as well as their functionality.

3. Procedure and Function Testing: The testers must test the database's procedures and functions and validate for the following points:

• • Is it true that the team followed the business requirements of the letter?
  • Is the code written in a way that follows best practices and suitable naming conventions?
  • Are the input and output parameters of these as expected?
  • Are there any exceptions?
  • Are the methods and functions properly entering data into the relevant tables?
  • Are the procedures and functions in place to update/modify data in the relevant tables?

4. Trigger testing: Trigger testing: Trigger testing is similar to process or functional testing in terms of testing rules. Aside from those rules, we must ensure that the triggers are triggered/executed at the appropriate times.

5. Database Server Testing: Tests on the database server Check to see if database configurations, RAM, CPU capacity, storage capacity, and other factors are in line with company needs. 

30. What is a trigger? And How do you verify if a trigger is fired or not? 

A piece of procedural code that is run in reaction to specific events on a database table or view. The integrity of the database is preserved by the use of triggers. We use a common audit log to see if the trigger has been fired or not. Triggers cannot be triggered on the fly. When an associated action (insert, remove, or update) occurs on the table where they are declared, the trigger is triggered. Triggers are used to perform business rules, audits, and referential integrity tests, although constraints should be used instead of triggers wherever possible because constraints are considerably faster.

31. How do you test the database triggers and procedures?

It is necessary to know the input parameters to database triggers and procedures in order to test them. It is also necessary to know the expected output for these functionalities. When procedures or triggers are executed, the EXEC statement can be used to determine how the tables will behave.

This can also be accomplished by writing SQL unit tests to verify the database objects that have been updated as a result of the triggers or procedures being executed. The three rules that apply to SQL unit tests are given below:

32. What are the possible test scenarios that need to be tested when a database gets migrated from one SQL server to another?

To begin, we must be aware of all the modifications and upgrades made in the new SQL server. Consider the following points when creating your test case suite based on this information:

• What is the data type that is being used?
• What is the length of the server's fields?
• Are the database objects in the new SQL server created as expected?
• Conduct stress testing on the new SQL server to discover any potential vulnerabilities in the newly migrated environment.

33. Why are SQL constraints used in a database?

SQL Constraints can be used to provide the rules for the database table's records. The action can be stopped if any constraints are not met. Constraints are defined when database objects are created. ALTER commands can also be used to change it. SQL has six major constraints:

• Not Null: This constraint is used to say that a column can't have any      Null values in it.
• Unique: This constraint ensures that each column has a distinct value, preventing values from being reused.
• Primary Key: This constraint combines the Not Null and Unique constraints, indicating that this key is used to uniquely identify a record in the database table in one or more combinations.
• Foreign Key: It is used to ensure that a record in a database table is referentially correct. It compares the value of a column in one table to the main key value in the other table.
• Check: This command is used to verify that the column values meet the stated criteria.
• Default: This constraint can be used to automatically add default values to the column if they are required. If the user specifies a value for the Default constraint, the default value will be saved in the table if we do not supply values for that column at the time of record creation.

34. How will you perform data load testing?

Data load testing necessitates knowledge of the source and destination databases, as well as its objects such as tables, columns, design, constraints, and so on. Using the DTS package in SQL Enterprise Manager, we need to confirm the compatibility of the source and destination databases when running tests. We can do so by following the instructions below:

• Run the DTS package.
• Compare the data in the source and destination tables' columns.
• In both the source and destination tables, count the number of rows.
• Check to see if the same changes are reflected in the destination database after updating data in source tables.
• Examine the data quality to see whether there are any trash characters or Null values in the destination data.
• Examine the maximum processable volume on the servers, as well as reaction times and data load speed from source to destination.

35. How can you test the data integrity in database testing?

When multiple modules in an application use the same data and execute various operations on it, it's critical that the most recent data be displayed everywhere. Systems should use the most recent data value. Data Integrity is the term for this. The graphic below depicts five qualities of data that are present once data integrity has been established:

The following test scenarios can be used to determine the data's integrity:

• Are all of the triggers for updating the records in the reference tables working properly?
• Is there any erroneous data in each database's columns?
• Insert incorrect data into the tables to observe how it behaves.
• What happens if you try to put the kid record in the main table before the parent record?
• Is there a chance you'll fail if you try to delete records that are linked to another table?
• Is there synchronization between the duplicated servers? Data in two or more replicated servers should not be out of sync, as this would defeat the purpose of replication.

36. What are the most commonly occurring issues that are faced during database testing and how can they be solved?

• To establish the status of transactions, there can be a significant amount of overhead.
• Solution: Design a time and cost-effective approach. When it comes to controlling database testing quality and application project duration, a delicate balance must be struck.
• After the old test data has been cleaned up, testers must create a new data design.
• Solution: Plan a technique and create test cases that can quickly adapt to various data types.
• An SQL generator that can help validate data and quickly handle different test scenarios is required to validate SQL queries. If not done appropriately, this maintenance can lead to a tangle of problems that are difficult to manage.
• Solution: The overall testing process should be well-planned, and queries should be well-maintained so that continual upgrades are possible.

37. What are the best practices that need to be followed while performing database testing?

While performing database testing, the following are some important practises keeping in mind:

• Validate each and every piece of data, including metadata and functional data, according to the requirements.
• After consulting with the development team, test data should be checked and prepared, and validation should be performed only after that.
• Both automated and human processes are required for validating output data.
• To obtain the appropriate test data inputs, do boundary value analysis, graphing techniques, and equivalence partitioning procedures.
• The data in the tables' referential integrity must also be thoroughly examined.
• In order to ensure data consistency, the table's default values must also be checked.
• Check to see that the right logging events have been recorded and saved in the database.
• Are the jobs that have been scheduled to run being completed on time?
• Ensure that a backup of the test database is taken on a regular basis to prevent test cases from failing.
• Ensure that the test server is refreshed with near-real-time data on a regular basis so that testing may be as accurate as feasible.

38. How can you validate the tables and columns in the database?

The following test cases can be used to evaluate the tables and columns in databases:

• Are the database fields accurately mapped and compliant with the front-end or back-end needs' needed mappings?
• Are the fields labelled correctly and have the correct lengths and sizes?
• Look for any tables or columns that aren't being used or haven't been mapped.
• Examine whether the table architecture, as well as the column referential integrities and constraints, are effective and scalable to varied requirements.

39. What are the differences between GUI Testing and Database Testing?

The below table shows the difference between GUI Testing and Database Testing:

GUI TESTING	DATABASE TESTING
Front-end testing is another term for user interface testing.	Data testing is another name for backend testing.
Tests all testable components in the programme that are visible to the user, such as forms, buttons, menus, and so on.	Tests all testable items which are not visible to users but are critical to the system's correct operation.
The tester does not need to be an expert in SQL.	To run queries and validate data, a tester must be familiar with database technologies such as SQL
It mostly concerns the software application's appearance and feelings.	Data integrity, schema validation of the structures where the data sits, validating data duplication, referential integrity, and everything else related to data are the main topics of discussion.
Katalon Studio, RAPISE by Inflectra, TestComplete, Abbot Java GUI Test Framework, and AutoIt UI testing are some of the technologies we utilize for GUI testing.	Database Rider, Db Stress, DbUnit, DB Test Driven, and others are some of the tools available.

40. How to test the Stored Procedures?

To test the Stored Procedures, the test engineer must follow a set of steps.

1. To begin, the test engineer must comprehend the need as well as the goal of a certain Stored Procedure.
2. Next, make sure that all of the indexes, joins, updates and deletions are accurate in comparison to the tables indicated in the Stored Procedure, and that the Stored Procedure is formatted in the common standard format, such as comments and updated by.
3. Then, for various sets of input parameters, double-check the procedure's calling name, parameters, and predicted outcomes.
4. Using database client programs like TOAD, MySQL, or Query Analyzer, run the method manually.
5. Rerun the method with varied settings to compare outcomes to expected values.
6. Finally, using QTP, automate the tests.

Conclusion

In the software testing area, the necessity for accurate data has increased dramatically. As a result, database testing aids in ensuring the data's accuracy, integrity, and truthfulness. We hope the above-covered database testing questions are useful for both newcomers and professionals.