POSTGRESQL

DATA : information.

Database : is a place where we can store out data.

Types of database:
types:

1. Rdbms: relational database managnment systom.
   • Rdbms : tables format (rows and columns). rdb type: example = mysql , oracle , microsoft server sql.

2) Ordbms = object relational database managnment systom.

      * postgresql  (only open sources)
      * graph database
      * mapping database

first of all what is sql ?
sql : structured query language // (neccessary details)
psql install : 2 type

      i)  cli: comment line interface
      ii)  ui: user interface

psql install step by step linux for (ui) method

       i)    start windows button
       ii)   search for software manager
       iii)  search for postgresql 

cli method install for linux

        i)open terminal
        ii)sudo apt update 
        iii) sudo apt install postgresql 

 iv)  check status = (sudo systemctl status postgresql) 

go to the inside 
          v)   -i -u postgres
          vi)   psql

 corrently  inside  a what data base this postgres 
           i) \l        //it will list all tha data base

            ii)\q        // just exit

              iii) create database student;

               iv) \c student;
      sql:

            1) data reterievel language/query language
            2) data manipilation language
                 * inselt,delete,update
            3) data definition language
                 * create,alter,drop,truncate

drop : drop tha table
truncate : remove tha inner all datas

            4) data control language
                    grant,revoke
            5) data transaction language
                    commit, rollback 



          (i) : create table student ( sno int, name varchar(30),age int,trainer varchar(20),doj date;

         ii) \dt        // (one database inside ,i need see this how many table )

          iii) inselt into student values ( 1, 'ranjith', 25, 'prithivi', '2025-09-25';

           just check this (select * from student; )


            key point 

         i)   sudo -i -u postgres
         ii)  psql
         iii) \l                            //it will list all tha data base
         iv)  create database student;
         v)   \c student;                    //just check 
         vi)  create table student ( sno int, name varchar(30),age int,trainer varchar(20),doj date;
         vii) \dt  //(one database inside ,i need see this how many table )

         viii) inselt into student values ( 1, 'ranjith', 25, 'prithivi', '2025-09-25';

           etha check panna (select * from student; )