DBMS Interview Questions | Eklavya Online

DBMS Interview Questions

What is the difference between a shared lock and exclusive lock?

Shared lock: Shared lock is required for reading a data item. In the shared lock, many transactions may hold a lock on the same data item. When more than one transaction is allowed to read the data items then that is known as the shared lock. Exclusive lock: When any transaction is about to perform …

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How do you communicate with an RDBMS?

You have to use Structured Query Language (SQL) to communicate with the RDBMS. Using queries of SQL, we can give the input to the database and then after processing of the queries database will provide us the required output.

What is the 3-Tier architecture?

The 3-Tier architecture contains another layer between the client and server. Introduction of 3-tier architecture is for the ease of the users as it provides the GUI, which, make the system secure and much more accessible. In this architecture, the application on the client-end interacts with an application on the server which further communicates with …

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What is 2-Tier architecture?

The 2-Tier architecture is the same as basic client-server. In the two-tier architecture, applications on the client end can directly communicate with the database at the server side.

What is the difference between a DELETE command and TRUNCATE command?

DELETE command: DELETE command is used to delete rows from a table based on the condition that we provide in a WHERE clause. DELETE command delete only those rows which are specified with the WHERE clause. DELETE command can be rolled back. DELETE command maintain a log, that’s why it is slow. DELETE use row …

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What is stored procedure?

A stored procedure is a group of SQL statements that have been created and stored in the database. The stored procedure increases the reusability as here the code or the procedure is stored into the system and used again and again that makes the work easy, takes less time in processing and decreases the complexity …

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Explain ACID properties

ACID properties are some basic rules, which has to be satisfied by every transaction to preserve the integrity. These properties and rules are: ATOMICITY: Atomicity is more generally known as ?all or nothing rule.’ Which implies all are considered as one unit, and they either run to completion or not executed at all. CONSISTENCY: This …

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What is BCNF?

BCNF stands for Boyce-Codd Normal Form. It is an advanced version of 3NF, so it is also referred to as 3.5NF. BCNF is stricter than 3NF. A table complies with BCNF if it satisfies the following conditions: It is in 3NF. For every functional dependency X->Y, X should be the super key of the table. …

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What is 3NF?

3NF stands for Third Normal Form. A database is called in 3NF if it satisfies the following conditions: It is in second normal form. There is no transitive functional dependency. For example: X->Z Where: X->Y Y does not -> X Y->Z so, X->Z