PostgreSQL, which is a powerful open-source relational database management system (RDBMS). PostgreSQL is known for its reliability, robustness, and support for advanced features.

1. Installation:
   • You can install PostgreSQL on various operating systems including Linux, macOS, and Windows.
   • You can download the installation files from the official PostgreSQL website: https://www.postgresql.org/download/
   • On Ubuntu/Linux:

   • sudo apt update
     sudo apt install postgresql postgresql-contrib
     

   • Start and enable PostgreSQL service:

   • sudo systemctl start postgresql
     sudo systemctl enable postgresql
     
     or 
     
     sudo systemctl start postgresql.service

   • On Windows:
   • Download the installer from: https://www.postgresql.org/download/windows/
   • Run the installer and follow the prompts.
   • Set a password for the default user postgres.

   • Install pgAdmin if you want a GUI.

      

2. Setup:
   • During installation, PostgreSQL will prompt you to set a password for the default database superuser (postgres). Remember this password as it's crucial for managing your PostgreSQL installation.
   • After installation, ensure that the PostgreSQL service is running.

Command Line Tools:

• Access PostgreSQL from Terminal
• For Linux/macOS:
  • Login as the default user:

  • Switch to the Postgres user (if required):

    sudo -i -u postgres
    
    or 
    
    sudo su postgres(user)
    [sudo] password for user: 

  • Open the PostgreSQL interactive terminal (psql):

    psql

  • You should see something like:

    postgres=#
    
    

• On Windows or Mac (if a password is set):
• PostgreSQL must be added to your system's PATH during installation. If not, you can manually add the bin directory (e.g., C:\Program Files\PostgreSQL\16\bin) to PATH.

• psql -U postgres
  

• -U postgres specifies you're connecting as the default user postgres.
• It will prompt you for a password (the one you set during installation).
• PostgreSQL provides command-line tools for database administration and management. The primary tool is psql, which is a terminal-based front end to PostgreSQL.
• You can access psql by opening your terminal/command prompt and typing psql.

Other information related to postgesql

Connect To the postgres server

psql -U postgres_username  -h database_host -p port_number    # to connect to server database

psql -U postgres_username -d database_name -h database_ip_address -p post_number  # connect server

psql -U user_name -d database_name; # connect with username and database name

psql -U username; # connect through username

Create a New User and Grant Permissions

CREATE USER myuser WITH PASSWORD 'mypassword';

# provide the privileges to the particular user to the particular database
GRANT ALL PRIVILEGES ON DATABASE mydb TO myuser;

#revoke the privileges
REVOKE ALL PRIVILEGES ON DATABASE mydb FROM blogadmin;

SELECT grantee, privilege_type
FROM information_schema.role_table_grants
WHERE grantee = 'amrit';

SELECT * FROM pg_roles WHERE rolname = 'amrit';


--If you want amrit to have role-level privileges like creating DBs:

ALTER ROLE amrit CREATEDB;
-- or make it a superuser
ALTER ROLE amrit SUPERUSER;

ALTER ROLE amrit NOSUPERUSER;

You can similarly revoke other attributes:

Additional commands 

drop user user_name;
drop role user_name;  # to delete the user 


create user user_name superuser; #to create useras superuserwhich have all access right
 
alter user user_name with password 'new_password';

SELECT rolname FROM pg_roles;

SQL:

• SQL (Structured Query Language) is the language used to interact with relational databases.
• Learn SQL syntax, including how to create databases, tables, insert data, retrieve data using SELECT statements, update and delete data, and perform basic aggregation functions.
• There are many online resources and tutorials available to learn SQL.

Data Types:

• PostgreSQL supports various data types such as integer, text, varchar, date, timestamp, boolean, etc. Familiarize yourself with these data types and their usage.

Constraints:

• PostgreSQL allows you to enforce data integrity using constraints such as NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK, etc.

Indexes:

• Indexes are used to improve the performance of database queries. Learn how to create indexes on tables based on your query patterns.

Transactions and Concurrency:

• Understand the concepts of transactions, isolation levels, and concurrency control in PostgreSQL.

Advanced Features:

• Once you're comfortable with the basics, explore advanced features such as stored procedures, triggers, views, user-defined types, and user-defined functions.

Advance Commands

1.To move the local file to the database

psql -U username -d data_base_name -f local_database_file.sql

it will move the local_database_file.sql to the postgres database (you need to crate the databse first to move in server)

2.Downlaod the server database to the local

pg_dump -U user_name -h host_ip_address -p db_port -d server_database_name > database_name_you_want_dump.sql

it will download the server_database_name database in your local with name database_name_you_want_dump