IT Lessons

Sunday, October 18, 2015

SQL Quereis SELECT * FROM Customers;

"Customers" table:

CustomerID	CustomerName	ContactName	Address	City	PostalCode	Country
1	Alfreds Futterkiste	Maria Anders	Obere Str. 57	Berlin	12209	Germany
2	Ana Trujillo Emparedados y helados	Ana Trujillo	Avda. de la Constitución 2222	México D.F.	05021	Mexico
3	Antonio Moreno Taquería	Antonio Moreno	Mataderos 2312	México D.F.	05023	Mexico
4	Around the Horn	Thomas Hardy	120 Hanover Sq.	London	WA1 1DP	UK
5	Berglunds snabbköp	Christina Berglund	Berguvsvägen 8	Luleå	S-958 22	Sweden

The table above contains five records (one for each customer) and seven columns (CustomerID, CustomerName, ContactName, Address, City, PostalCode, and Country).

Some of The Most Important SQL Commands

SELECT - extracts data from a database
UPDATE - updates data in a database
DELETE - deletes data from a database
INSERT INTO - inserts new data into a database
CREATE DATABASE - creates a new database
ALTER DATABASE - modifies a database
CREATE TABLE - creates a new table
ALTER TABLE - modifies a table
DROP TABLE - deletes a table
CREATE INDEX - creates an index (search key)
DROP INDEX - deletes an index

The following SQL statement selects all the records in the "Customers" table:

SELECT * FROM Customers;

SQL is NOT case sensitive: select is the same as SELECT

Semicolon is the standard way to separate each SQL statement in database systems that allow more than one SQL statement to be executed in the same call to the server

SQL SELECT Syntax

SELECT column_name,column_name
FROM table_name;

SELECT * FROM table_name;

SELECT Column Example

The following SQL statement selects the "CustomerName" and "City" columns from the "Customers" table:

Example

SELECT CustomerName,City FROM Customers;

SELECT * Example

The following SQL statement selects all the columns from the "Customers" table:

Example

SELECT * FROM Customers;

Monday, March 2, 2015

PHP MySQL HTML Code: Create database & Create Table, Add, edit Search...

PHP MySQL HTML Code: Create database & Create Table, Add, edit Search...: create database DBname; CREATE TABLE people (name VARCHAR(30), age INTEGER, height FLOAT, date DATETIME); INSERT INTO people VALUES (...

Create database & Create Table, Add, edit Search Delete in MySQL

create database DBname;

CREATE TABLE people (name VARCHAR(30), age INTEGER, height FLOAT, date DATETIME);

INSERT INTO people VALUES ( "Jim", 45, 1.75, "2006-02-02 15:35:00" ), ( "Peggy", 6, 1.12, "2006-03-02 16:21:00" )

UPDATE people SET age = 7, date = "2006-06-02 16:21:00", height = 1.22 WHERE name = "Peggy"
SELECT name FROM people WHERE age < 12
DELETE FROM people WHERE age < 12

Friday, February 6, 2015

Open a Connection to MySQL

<?php
$servername = "localhost";
$username = "username";
$password = "password";

// Create connection
$conn = new mysqli($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>

Thursday, January 29, 2015

HTML Comment

<p>This is a paragraph.</p>

Wednesday, January 21, 2015

PHP with HTML

<html>

<body>

<h1>My Example</h1>

<?php //your php code here ?>

<?php //more php code ?>

</body>

</html>

_________________________________________________________________

<?php Echo "<html>";

Echo "<title>HTML with PHP</title>";

Echo "<b>My Example</b>";

//your php code here

Print "<i>Print works too!</i>"; ?>

PHP Sessions

A session is a way to store information (in the form of variables) to be used across multiple pages. Unlike a cookie, specific variable information is not stored on the users computer. It is also unlike other variables in the sense that we are not passing them individually to each new page, but instead retrieving them from the session we open at beginning of each page.

Call this code mypage.php

<?php // this starts the session session_start();

// this sets variables in the session

$_SESSION['color']='red';

$_SESSION['size']='small';

$_SESSION['shape']='round';

print "Done"; ?>


Now we are going to make a second page. We again will start with session_start() (we need this on every page) - and we will access the session information we set on our first page. Notice we aren't passing any variables, they are all stored in the session.


Call this code mypage2.php

<?php  // this starts the session  session_start(); 

 // echo variable from the session, we set this on our other page 

 echo "Our color value is ".$_SESSION['color'];

 echo "Our size value is ".$_SESSION['size']; 

 echo "Our shape value is ".$_SESSION['shape'];  ?>




All of the values are stored in the $_SESSION array, which we access here. Another way to show this is to simply run this code:


<?php  session_start();  Print_r ($_SESSION); ?>




Modify or Remove a Session




<?php  
// you have to open the session to be able to modify or remove it  session_start(); 
 // to change a variable, just overwrite it
 $_SESSION['size']='large'; 
 //you can remove a single variable in the session  unset($_SESSION['shape']);
 // or this would remove all the variables in the session, but not the session itself 
 session_unset(); 
 // this would destroy the session variables 
 session_destroy();  ?>