Top Database | DBMS Interview Questions With Answers Part 1
1. What is DBMS?
Database Management System is defined as the technology of storing and retrieving users' data with utmost efficiency along with appropriate security measures.
2. What is a database?
A database is a collection of information that is organized so that it can easily be accessed, managed, and updated.
3. What is a database system?
In this Database System, a general-purpose DBMS is designed to allow the definition, creation, querying, update, and administration of databases.
4. What are the advantages of DBMS?
- Redundancy control
- Restriction for unauthorized access
- Provides multiple user interfaces
- Provides backup and recovery
- Enforces integrity constraints
5. How many types of database languages are?
- Data Definition Language (DDL) e.g. CREATE, ALTER, DROP etc.
- Data Manipulation Language (DML) e.g. SELECT, UPDATE, INSERT etc.
- DATA Control Language (DCL) e.g. GRANT and REVOKE.
- Transaction Control Language (TCL) e.g. COMMIT and ROLLBACK
6. What is normalization?
- Normalization is a systematic approach of decomposing tables to eliminate data redundancy and undesirable characteristics like Insertion, Update and Deletion Anamolies.
- It is a multi-step process that puts data into tabular form by removing duplicated data from the relation tables.
7. What is Denormalization?
In computing, denormalization is the process of trying to improve the read performance of a database, by adding redundant copies of data or by grouping data.
8. What are the types of normalization?
- First Normal Form
- Second Normal Form
- Third Normal Form
- Boyce & Codd normal form (BCNF)
- Fourth Normal Form
- Fifth Normal Form
9) What is 1NF?
- As per the rule of first normal form, an attribute (column) of a table cannot hold multiple values.
- It should hold only atomic values.
10) What is 2NF?
A table is said to be in 2NF if both the following conditions hold:
- Table is in 1NF (First normal form)
- No non-prime attribute is dependent on the proper subset of any candidate key of table.