MySQL is the most popular Open Source Relational SQL database management system. MySQL is one of the best RDBMS being used for developing web-based software applications.

RDBMS Terminology: Before we proceed to explain MySQL database system, let’s revise few definitions related to database.

Database: A database is a collection of tables, with related data. Table: A table is a matrix with data. A table in a database looks like a simple spreadsheet. Column: One column contains data of one and the same kind, for example the column postcode. Row: A row is a group of related data, for example the data of one subscription. Primary Key: A primary key is unique. A key value can not occur twice in one table. With a key, you can find at most one row. Foreign Key: A foreign key is the linking pin between two tables.

Installing Process [root@host]# rpm -i MySQL-client-5.0.9-0.i386.rpm [root@host]# rpm -i MySQL-level-5.0.9-0.i386.rpm [root@host]# rpm -i MySQL-shared-5.0.9-0.i386.rpm [root@host]# rpm -i MySQL-bench-5.0.9-0.i386.rpm

Query in MySQL: Basic Queries are

Create database Creating separate space in MySQL.

Syntax: create database ; To use the created Database

Syntax: use ; Create table Creating table in Database

Syntax: create table (Column1 Datatype,Column2 Datatype,...); Insert table Insert data in created table

Syntax: insert into values('string_data',integer_data,....); Select table

To retrieve data from table

Syntax for access all Rows: select * from ; (or) select from ; Syntax for access particular Rows: select * from where ='<user_data'>; View table

Create view table form existing table.

Syntax: create view as select , from ; Delete table

To delete data or table

Syntax for delete all data: delete table ; Syntax for delete particular data: delete table where =" " MySQL aggregate functions: Avg

The AVG function calculates the average value of a set of values. It ignores NULL values in the calculation.

Syntax: select AVG(<columnname) from="" <tablename="">; Count

The COUNT function returns the number of the rows in a table.

Syntax: select COUNT(*) from (or) select COUNT() from ; Sum

The SUM function returns the sum of a set of values.

Syntax: select SUM() from ;

Min The MIN function returns the minimum value in a set of values. Syntax: select MIN() from ;

Max The MAX function returns the maximum value in a set of values.

Syntax: select MAX() from ; MySQL with node.js Example:

var express    = require("express");   
var mysql      = require('mysql');  
var connection = mysql.createConnection({   
    host     : 'localhost',       
    user     : 'root',                
    password : '',                
    database : 'address_book'         
}); 

var app = express();
connection.connect(function(err){   
    if(!err) {
        console.log("Database is connected ... nn");
    } else {
        console.log("Error connecting database ... nn");   
    }
});

app.get("/",function(req,res){
    var query="select * from register where 
    urname='"+req.body.urname+"' and pw='"+req.body.pw+"'";
    connection.query(query, function(err, 
    rows, fields) {    
    connection.end();
    if (!err)
        console.log('The solution is: ', rows);
    else
        console.log('Error while performing Query.');
    });
});
app.get("/",function(req,res){
    connection.query('insert into user values('+1+','+sathiya+','+sathiya@gmail.com+','+sathiya2901+')', function(err, rows, fields) { 
    connection.end();
    if (!err)
        console.log('The solution is: ', rows);
    else
        console.log('Error while performing Query.');
    });
});
app.listen(3000);  

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