Q1. What is RDBMS?
Ans. An RDBMS or Relational Database Management System is a type of DBMS having relationships between the tables using indexes and different constraints like primary key, foreign key etc. The use of indexes and constraints helps in faster retreival and better management of data within the databases.
Q2. What is the difference between DBMS and RDBMS?
Ans. The primary difference between DBMS and RDBMS is, in RDBMS we have relations between the tables of the database. Whereas in DBMS there is no relation between the tables(data may even be stored in files).
RDBMS has primary keys and data is stored in tables. DBMS has no concept of primary keys with data stored in navigational or hierarchical form.
RDBMS defines integrity constraints in order to follow ACID properties. While DBMS doesn’t follow ACID properties.
Q3. What is a database?
Ans. A database is a structured collection of data for faster and better access, storage and manipulation of data.
A database can also be defined as collection of tables, schema, views and other database objects.
Q4. What is a table?
Ans. Tables are the database object that are used for storing related records in the form of rows and columns.
Q5. What is field in a table?
Ans. A field is an entity used for storing a particular type of data within a table like numbers, characters, dates etc.
Q6. What is a tuple, record or row in a table?
Ans. A tuple or record is an ordered set of related data item in a table.
Q7. What is SQL?
Ans. SQL stands for Structured Query Language, it is an language used for creating, storing, fetching and updating of data and database objects in RDBMS.
Q8. What are the different types of SQL commands?
Ans. SQL commands are the set of commands used to communicate and manage the data present in the database. The different type of SQL commands are-
- DDL – Data Definition Language
- DML – Data Manipulation Language
- DCL – Data Control Language
- TCL – Transactional Control Language
Q9. Explain DDL commands. What are the different DDL commands in SQL?
Ans. DDL refers to Data Definition Language, it is used to define or alter the structure of the database. The different DDL commands are-
- CREATE – Used to create table in the database
- DROP – Drops the table from the database
- ALTER – Alters the structure of the database
- TRUNCATE – Deletes all the records from the database but not its database structure
- RENAME – Renames a database object
Q10. Explain DML commands. What are the different DML commands in SQL?
Ans. DML refers to Data Manipulation Language, it is used for managing data present in the database. Some of the DML commands are-select, insert, update, delete etc.