Tags: , | Categories: QA Interview Questions
Posted by trainer on 10/3/2012 3:26 PM |

1. What is SQL?
SQL stands for Structured Query Language. SQL is an ANSI (American National Standards Institute) standard computer language for accessing and manipulating database systems. SQL statements are used to retrieve and update data in a database. SQL works with database programs like MS Access, DB2, Informix, MS SQL Server, Oracle, Sybase, etc.

Unfortunately, there are many different versions of the SQL language, but to be in compliance with the ANSI standard, they must support the same major keywords in a similar manner (such as SELECT, UPDATE, DELETE, INSERT, WHERE, and others).

Note: Most of the SQL database programs also have their own proprietary extensions in addition to the SQL standard.

2. Where do you write SQL query?
We write SQL queries using some these tools: SQL Client, Todd, Squirrel and Rapid SQL.

3. Do you really need to write SQL as a QA Engineer?
Yes. You need to. No matter whether it is a small company or big, they have a database and you need to validate the data by writing SQL queries going into the database. The stronger you are in SQL, the better the chance of getting a job.

4. What is the most common syntax you have used while writing SQL query?

5. What is a Primary Key?
In a database table, the Primary Key is a column which has a unique value for each of the row within that column. It can’t have NULL value.

6. What is a Unique Key?
In a database table, the Unique Key is a column which may or may not have null value of each of the row within that column.

7. What is Data?
Data is a number, character or image which has some information.

8. What is a Database?
It is a collection of logically related data designed in a tabular form to meet the information needs of one or more users.

9. What is Change Control (or Change Request)?
It is a document that describes the additional functionalities that are added after the Business Requirement Document is signed off. It can be updated in the old business requirement document or it can be a separate document.

10. What is Backend Testing?
It is a test to check whether the data displayed in the GUI front end report format matches with the particular data in the original database.

11. How can you be sure that the query you wrote is correct? Or how do you know that the data you pulled from the database is correct?
I write SQL query based on the requirement document. In the requirement document, various conditions are given for the query. Based on those conditions, I write SQL query. Therefore, anything different from the requirement document is definitely a defect.

12. What is XML?
- XML stands for EXtensible Markup Language.
- XML is a markup language much like HTML.
- XML was designed to describe data.
- XML tags are not predefined and we must define our own tags.
- XML uses a Document Type Definition (DTD) or an XML Schema to describe data.
- XML with a DTD or XML Schema is designed to be self-descriptive.
- XML is a W3C Recommendation.