SQL Fundamentals

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Questions and Answers

What is the purpose of the SQL query 'Alter table Student Add adhrno int;'?

To delete the records of students with age less than 19

To rename the column 'course' to 'course_name'

To add a new column 'adhrno' to the Student table (correct)

To update the age of a student with admnno 103 to 20

What is the outcome of the SQL query 'Update Student set age=20 where admnno=103;'?

The age of the student with admnno 103 will be updated to 20 (correct)

The student with admnno 103 will be deleted from the table

A new student with admnno 103 will be added to the table

The age of all students will be updated to 20

What is the effect of the SQL query 'Delete from Student where age<19;'?

A new column 'age' will be added to the Student table

Students with age less than 19 will be updated to 19

The age of all students will be updated to 19

Students with age less than 19 will be deleted from the table (correct)

What is the purpose of the CREATE command in SQL?

To create a new database object like a table or index Signup and view all the answers

What is the purpose of the SQL query 'Create table Student (admnno int, name varchar (30), course varchar (30), age int);'?

To create a new table named Student with specified columns Signup and view all the answers

Which SQL command is used to add a new record to a database?

INSERT Signup and view all the answers

What is the outcome of the SQL query 'Alter table Student Rename column course to course_name;'?

The column 'course' will be renamed to 'course_name' Signup and view all the answers

What is the purpose of the SQL query 'Select * from Student;'?

To display all columns and rows of the Student table Signup and view all the answers

What is the purpose of the Data Query Language (DQL) in SQL?

To retrieve specific data from a database Signup and view all the answers

What is the purpose of the GRANT command in SQL?

To give a privilege to a user Signup and view all the answers

Which type of SQL statement is used to update an existing database object?

DDL Signup and view all the answers

What is the purpose of theDROP command in SQL?

To delete an entire table, view, or other objects in the database Signup and view all the answers

What is the purpose of the SELECT command in SQL?

To retrieve certain records from one or more tables Signup and view all the answers

Which type of SQL statement is used to control access to databases?

DCL Signup and view all the answers

What is the primary function of SQL queries?

To interact with databases and retrieve data Signup and view all the answers

What is the purpose of constraints in a SQL system?

To ensure data integrity and consistency Signup and view all the answers

What is the name of the language used to create database structures?

Data Definition Language Signup and view all the answers

What is the acronym of the original name given to SQL by IBM?

SEQUEL Signup and view all the answers

What is the role of a database in a SQL system?

To store and manage data efficiently Signup and view all the answers

What is the fundamental building block of a database?

Table Signup and view all the answers

What is the outcome of executing a SQL query?

Retrieval of requested data from the database Signup and view all the answers

Who developed SQL in the 1970s?

IBM Computer Scientists Signup and view all the answers

Study Notes

What is SQL?

SQL stands for Structured Query Language and is a standard database language used to access and manipulate data in databases.
It was developed by IBM Computer Scientists in the 1970s.

Components of a SQL System

Databases: structured collections of data organized into tables, rows, and columns that serve as repositories for storing information efficiently.
Tables: fundamental building blocks of a database, consisting of rows (records) and columns (attributes or fields) that ensure data integrity and consistency.
Queries: SQL commands used to interact with databases, enabling users to retrieve, update, insert, or delete data from tables.
Constraints: rules applied to tables to maintain data integrity, defining conditions that data must meet to be stored in the database.

Functions of SQL

Data Definition Language (DDL): SQL commands used to create the database structure.
Data manipulation: allows users to add new data, remove data, or modify existing data.
Data retrieval: used for retrieving data from databases.
Access control: restricts a user's ability to retrieve, add, and modify data, protecting stored data against unauthorized access.
Data sharing: coordinates data sharing by concurrent users, ensuring that changes made by one user do not inadvertently wipe out changes made by another user.

SQL Commands

CREATE: creates a new table, a view of a table, or other object in the database.
ALTER: modifies an existing database object, such as a table.
DROP: deletes an entire table, a view of a table, or other objects in the database.
SELECT: retrieves certain records from one or more tables.
INSERT: creates a record.
UPDATE: modifies records.
DELETE: deletes records.
GRANT: gives a privilege to the user.
REVOKE: takes back privileges granted by the user.

Uses of SQL

Interacting with databases, including:
- Data definition: defining the structure and organization of the stored data and the relationships among the stored data items.
- Data retrieval: retrieving data from databases.
- Data manipulation: adding new data, removing data, or modifying existing data.
- Access control: restricting a user's ability to retrieve, add, and modify data.
- Data sharing: coordinating data sharing by concurrent users.

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Description

Learn about the basics of SQL, a standard database language. Discover its components, including databases and tables, and how they store information efficiently.