Database Testing Complete Guide (Why, What, and How to Test Data)

An In-depth Guide on Database Testing with Practical Advices and Examples:

With the advancement of technology and the rise of Android devices and Smartphone applications, computer software is becoming increasingly convoluted. As the front-end interfaces become more elaborate, the backend follows suit.

As such, it is fundamental to comprehend database testing and be proficient in verifying databases to secure their safety and quality.

Within this guide, you’ll grasp the significance of data testing, as well as the method and subject of testing.

Databases are vital for any software program, regardless if it’s a web, desktop, or mobile application, a client-server or peer-to-peer network, an enterprise or a small business. Databases are consistently required in the backend.

As the sophistication of applications rises, the necessity for more robust and secure databases ascends as well. High-transaction applications, like banking or financial software, demand fully-equipped database tools.

Traditional databases often stumble when faced with the size and complexity of modern big data. However, multiple database tools like MS-Access, MS SQL Server, SQL Server, Oracle, Oracle Financial, MySQL, PostgreSQL, DB2, Toad, Admirer, and others are available in the market. Each tool provides its own pricing, robustness, features, and security.

For more information, read our article on PostgresSQL Vs MySQL.

Reasons to Test Databases

We’ll delve into the justifications for authenticating the subsequent aspects of a database:

#1) Data Mapping

In digital systems, data frequently travels from the user interface (UI) to the backend database. Hence, it is critical to validate the subsequent aspects:

• Examine if UI/frontend form fields align consistently with the concurrent fields in the database table. This mapping metadata is typically articulated in the requirements documentation.
• Guarantee the correct action is summoned at the backend when a particular action is executed on the front end. For instance, when a user engages in an “Save” or “Update” action, the corresponding CRUD operation should activate in the backend.

#2) Validation of ACID Attributes

Database transactions should adhere to the ACID attributes:

• Atomicity: All or nothing applies to transactions. This indicates that if a portion of the transaction fails, the entire transaction should be deemed as failed.
• Consistency: Database validity should always be the result of a transaction.
• Isolation: If multiple transactions are concurrently executed, the database state or result should resemble sequential transaction execution.
• Durability: Despite external factors like power disruptions or crashes, a committed transaction should remain unchanged.

#3) Maintaining Data Integrity

The most recent values/status of shared data should remain consistent across all forms and screens for any CRUD operation. It is crucial to validate the integrity of data throughout the application, ensuring that data is not updated on one screen while displaying an outdated value on another.

#4) Compliance With Business Rules

Complex databases often involve elements such as relational constraints, triggers, and stored procedures. Hence, it is imperative to validate these intricate objects by executing appropriate SQL queries.

What to Verify (Database Assessment Checklist)

#1) Transactions

When verifying transactions, it is important to ensure they fulfill the ACID attributes.

Commonly utilised statements include:

• BEGIN TRANSACTION TRANSACTION#
• END TRANSACTION TRANSACTION#

The rollback statement plays a key role in database consistency:

• ROLLBACK TRANSACTION TRANSACTION#

After the execution of these statements, a SELECT statement can be used to confirm the alterations:

• SELECT * FROM TABLENAME <tables implicated in the transactions>

#2) Database Schemas

Database schemas illustrate how data is organised within a database. To inspect them:

• Recognise the prerequisites:
  • Establish primary keys ahead of other fields.
  • Ensure adequate foreign key indexing for efficient data retrieval and search.
  • Validate field names that start or end with specific characters.
  • Check fields with constraints on certain values.
• Adopt one of the following strategies:
  • Execute the SQL query DESC <table name> to validate the schema.
  • Employ regular expressions to confirm field names and values.
  • Utilise tools like SchemaCrawler.

#3) Triggers

Triggers are fragments of code that are automatically executed when predefined events occur on a table. They can help maintain referential integrity, automate tasks, or update secondary data.

When testing triggers:

• Execute the SQL query incorporated within the trigger independently, record the result, and then run the trigger as a whole to compare results.
• Triggers should be examined during black-box and white-box testing phases. For white-box testing, utilise stubs and drivers, while for black-box testing, replicate actions that would activate the trigger and confirm the results.

#4) Stored Procedures

Stored procedures resemble user-defined functions. They can be invoked using call or execute statements and usually produce result sets. Stored procedures are preserved within the database, available for applications to utilise.

To test stored procedures:

• In white-box testing, use stubs to invoke the stored procedures and validate the output.
• For black-box testing, execute operations from the front end and check if the stored procedure is accurately executed with the expected results.

#5) Field Constraints

Field constraints, such as default values, unique values, and foreign keys, ensure the precision and integrity of data in the database.

To test field constraints:

• Perform front-end operations that challenge the conditions of the database object.
• Validate the results with corresponding SQL queries.

Tasks for Data Testing

Database testers should concentrate on the following testing tasks:

#1) Confirm Data Mapping:

Authenticate the mapping between differing application forms or screens and its database. Validate that the mapping is precise and in line with the design records (SRS/BRS) or code. Test CRUD operations to make sure that tables and records are accurately updated.

#2) Validate ACID Attributes of Transactions:

Test each transaction to ascertain its adherence to the ACID attributes. Atomicity, consistency, isolation, and durability must be secured for each transaction.

#3) Ensure Data Integrity

Confirm that shared data appears consistently and is accurate across all forms and screens. Verify if triggers are correctly updating reference table records. Validate the condegrity of major columns in each table.

#4) Ensure Business Rule Correctness:

Validate the correctness of business rules implemented in the database using capabilities such as referential integrity, relational constraints, triggers, and stored procedures. Ensure that executed business logic works correctly and accurately.

How to Evaluate Databases (Stepwise Approach)

The all-encompassing test procedure for database testing is not dissimilar from testing other applications.

These are the prime steps:

Step #1) Set up the environment.
Step #2) Perform a test.
Step #3) Evaluate the test outcomes.
Step #4) Compare the results with the expected outcomes.
Step #5) Report the outcomes to the concerned stakeholders.

SQL queries are frequently used in database testing, particularly the SELECT statement. Other fundamental types of SQL commands include:

1. Data definition language (DDL): Commands such as CREATE, ALTER, RENAME, DROP, and TRUNCATE for managing tables and indexes.
2. Data manipulation language (DML): Statements for adding, updating, and deleting records.
3. Data control language (DCL): Commands that grant and revoke data manipulation and access authorisations.

Effective Suggestions

#1) Formulate Queries Independently:

Gaining a thorough understanding of SQL and DML statements is crucial for database testing accuracy. Merge GUI and data verification for superior coverage. Use SQL Query Analyzer or similar tools to compose, execute, and retrieve results of SQL queries. This is an efficient way to test databases in applications of small to medium complexity.

#2) Examine Data in Each Table:

Whenever possible, manually verify data using CRUD operation results. This method necessitates a sound understanding of database table structure.

#3) Obtain Queries from Developers:

Request developers for queries that simulate the effects of CRUD actions triggered through the GUI. This approach doesn’t demand extensive SQL or database structure knowledge. Nevertheless, be wary and ensure the developer-issued queries meet user requirements.

#4) Utilise Database Automation Testing Tools:

There’s a plethora of tools available for database testing. Choose the tool that best aligns with your requirements and put it to efficient use.

Conclusion

Database testing is a pivotal facet of software testing that ensures data quality and security. Testing databases can be complex, but with the rapid technological advances in today’s applications, it’s become a necessity. Armed with the accurate knowledge and useful tips, performing database testing efficiently and effectively is achievable.

If you have any input or personal encounters regarding database testing, we’d love to hear from you.