PostgreSQL day-1

DBMS:

• DBMS stands for "Database Management System"

• It is used to manage the data from the database

• DBMS is a software is allow to create, update and retrieval of data in a Organized way

RDBMS:

• RDBMS stands for "Relational Database Management System"

• RDBMS is a program used to maintain relational Database.

• The data in RDBMS store in table format . A table is a collection of related entity (entity means things).

SQL:

• SQL stands for "Structured Query Language".

• SQL lets you access and manipulate databases.

PostgreSQL:

• PostgreSQL is a Relational Database Management System

• It is a open source RDBMS it is used to store, manage, retrieve and Manipulate the data

Difference between PostgreSQL and MySQL

PostgreSQL	MySQL
More advanced	Beginner friendly
Open Source	Open Source
Large applications	Small & Medium applications
Better performance for complex queries	Faster for simple queries

Installation of PostgreSQL:

1. sudo apt update
2. sudo apt install postgresql postgresql-contrib
3. sudo systemctl status postgresql
4. sudo systemctl enable postgresql
5. sudo -i -u postgres
6.PSQL

comments of PostgreSQL

\h ---> help
\l ---> list
\r ---> stop/recover
\c ---> connect

CREATION OF DATABASE:

CREATE database college;
\c ---> connect the database

*TABLE CREATION *

CREATE table student(
stdroll int,
stdname varchar(20),
department varchar(10),
year int,
);

INSERT DATA INTO A TABLE:

// single value insert
INSERT INTO student values ('01','shobi','CSE',4);

// multiple value insert
INSERT INTO student values ('02','shiva','ECE',3),('03','ajitha','EEE',2);

// we can change the order of the values
INSERT Into student (stdname, stdroll, department, year) values ( 'abi','09','IT',1);

SELECT THE VALUES IN A TABLE

SELECT * from student;