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Database Interview Questions: Read these before you go

Preparing for Database Administrator Job? Here is what you should know before you start your job search.

Database Administrators – Are you qualified?

Database Administrators (DBAs) are accountable for evaluating database software purchases. They oversee the amendment of any existing database software to cover their employer’s needs.

The DBA maintains the performance and integrity of company databases and ensures that data is stored optimally and securely. DBAs inform end users of database changes and educate them to use systems. The highest demand for DBAs is in data-intensive companies like finance, insurance and content providers.

To apply for a Database Administrator position you will need a bachelor’s degree in computer science or Information Technology. Also, certifications and advanced education. When you have the qualifications and your resume the first step is applying for a position. If you are successful in getting call for the interview it is worthwhile studying the questions you will be asked.

Database Interview Questions

1. Define Database.

A programmed collection of figures (data).

2. What is Database Management Systems (DBMS)?

Data Management Systems are applications calculated to allow user interaction with other applications.

3. What are the various kinds of interactions provided by DBMS?

The various kinds of interactions are:

• Data Definition.

• Update.
• Retrieval.
• Administration.

4. What are the features of Database language?

A database language may include features like DBMS-specific Configuration and the organisation of the storage engine.

Constraint Enforcement Application Programming Interface – Computations to alteration of query consequences by calculations like:

• Counting.

• Averaging.
• Summing.
• Grouping.
• Sorting.
• Cross-Referencing.

5. Define the Database Model.

A database model is a data model that controls how data can be stored, controlled and arranged.

6. List the Various Database Relationships.

The various database relationships are:

• One-to-One – A single table with a connection to another table has similar columns.

• One-to-Many – Two tables with foreign and primary key relationships.
• Many-to-Many – Junction tables having numerous related tables.

7. Compare Non-Clustered and Clustered Index.

Both have a B-tree structure. However, a clustered index is different for every table while the non-clustered index has data pointers allowing on the table many non-clustered indexes.

8. Define ‘Correlated Subqueries’.

A ‘correlated subquery’ is a subquery reliant on another query for a returned value. In the case of execution, the subquery is executed first and then the correlated query.

9. Define Data Warehousing.

Data Warehousing is the storing and access of data from a central location. This allows a strategic decision. Enterprise Management is used for controlling the information of the framework known as Data Warehousing.

10. What do You Mean by Index Hunting?

Indexes improve the speed and the query performance of a database. Index Hunting is the process of enhancing the collection of indexes.

11. How does Index Hunting Help in Improving Query Performance?

Index Hunting helps in enhancing the speed and the query performance of the database.

The following measures achieve this:

• Tuning databases to a small group of problem queries is recommended.

• Index query distribution performance is noted to check the effect.
• The query optimiser co-ordinates the study of queries with the workload and the best use of queries based on this.

12. How Does Index Hunting Help in Improving Query Performance?

Index Hunting helps in increasing the query performance and speed of the database. The following measures will achieve this:

• The query optimizer is used to synchronise the queries study with the workload.

• Index query distribution along with their performance is noted to check the effect.
• Databases are tuned to a small collection of problem queries.

13. Enlist the Disadvantages of Query.

The disadvantages are:

• No indexes.

• Procedures or triggers are without SET NOCOUNT ON.
• Complicated joins make up inadequately written query.
• Stored procedures are excessively complied.
• Temporary tables and cursors showcase a bad presentation.

14. Explain the Importance of Positioning.

Database Positioning is the logical splitting of a large table into smaller database entities. Its benefits are:

• Dramatic improvement of query performance in situations when heavily accessed rows are in one partition.

• The capability to access large sections of a single partition.
• Cheaper and slower storage media can be used for data which is seldom used.

15. Define the Object-Oriented Model.

Sets of objects make up this model in which values are kept within instant variable inside the object. The object itself includes bodies of objects for its operation which are called methods. Objects with the same kind of methods and variables are called classes.

You should believe in automation and be adaptable because it makes you more productive. However, computers and robots can never replace human specialised expertise or skills. Think about how you can contribute to the business success and customer satisfaction.

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