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Connecting PHP and MySQL · 2012. 2. 27. · Connecting PHP and MySQL 1 . Outline • PHP Loops •...

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  • Connecting PHP and MySQL

    1

  • Outline

    • PHP Loops

    • PHPMyAdmin

    • Introducing SQL

    • Connecting Database from PHP

    • Exercises

    2

  • Loops

    • A loop statement is a control structure that repeatedly executes a statement or a series of statements while a specific condition is TRUE or until a specific condition becomes TRUE

    • Three different types of loops are:

    • while statements

    • do...while statements

    • for statements

    3

  • While Loop

    • Tests the condition prior to executing the series of statements at each iteration of the loop

    • The syntax for the while statement is: while (conditional expression) {

    statement(s);

    }

    • As long as the conditional expression evaluates to TRUE, the statement or command block that follows executes repeatedly

    4

  • While Loop • Each repetition of a looping statement is called an iteration.

    • A while statement keeps repeating until its conditional expression evaluates to FALSE

    • A counter is a variable that increments or decrements with each iteration of a loop statement.

    • In an infinite loop, a loop statement never ends because its conditional expression is never FALSE $Count = 1;

    while ($Count

  • The while Structure

    • PHP supports the C style while loop

    – The body of the cycle will be executed until the condition is met

    – The body consists of one or more statements

    • If more than one, surrounding braces are required

    – The condition expression is of type boolean

    $a = 1;

    while ($a < 100) {

    $a ++;

    echo $a;

    }// this will output

    expression

    body

    6

    2 3 4 … 99

  • Do .. While Loop

    • Test the condition after executing a series of statements then repeats the execution as long as a given conditional expression evaluates to TRUE

    • The syntax for the do...while statement is: do {

    statement(s);

    } while (conditional expression);

    7

  • Do .. While Cont’d

    • do...while statements always execute once, before a conditional expression is evaluated

    $Count = 2;

    do {

    echo "

    The count is equal to

    $Count

    ";

    $Count++;

    } while ($Count < 2);

    8

  • do… while Structure

    • The do-while structure is similar to while-do

    – The condition is checked after the body is executed!

    – The body is executed at least once!

    $a = 1;

    do {

    $a ++;

    echo $a;

    } while ($a < 100);

    //this will produce

    //the previous while cycle’s output was: 2 3 4 … 99

    expression

    body

    9

    2 3 4 … 100

  • For Loop

    • Combine the initialize, conditional evaluation, and update portions of a loop into a single statement.

    • Repeat a statement or a series of statements as long as a given conditional expression evaluates to TRUE.

    • If the conditional expression evaluates to TRUE, the for statement executes and continues to execute repeatedly until the conditional expression evaluates to FALSE.

    10

  • for Cycle

    • PHP supports C style for cycles

    – The for cycle requires initialization, iteration and

    ending condition statement • None of them are obligatory • Each statement can consist of multiple comma

    separated statements

    for ($i = 0; $i < 10; $i++)

    echo $i;

    for ($i = 0, $j = 10; ; $i++, $j--)

    if ($j > $i)

    echo $i;

    else break;

    body

    initialization end condition iteration

    11

  • break and continue

    • You can leave a cycle with the break command

    • You can move immediately to next cycle iteration with continue command

    $i = 0;

    while (true) {

    $i ++;

    if ($i == 10) break; // exit the cycle

    if ($i%2 == 0) continue; // next iteration

    echo $i;

    }

    12

    $i = 0;

    while ($i < 10) {

    if ($i%2 == 1)

    echo $i;

    $i ++;

    }

    for ($i = 1; $i < 10; $i+2)

    echo $i;

    will print out 1 3 5 7 9

  • Exercise #3

    • Using PHP loops, make this HTML table.

    13

    width = '50'

    Colorful_list.php

  • Outline

    • PHP Loops

    • PHPMyAdmin

    • Introducing SQL

    • Connecting Database from PHP

    • Exercises

    14

  • From, Tools

    phpMyAdmin, we can

    manage MySQL

    15

  • What is phpMyAdmin?

    • PhpMyAdmin is a Web-based front end for managing mySQL databases.

    • It has GUI screen for many common functions in mySQL.

    • Makes mySQL more user friendly.

  • About phpMyAdmin

    • Project started in 1998

    • Uses GNU General Public License

    • Platform independent

    • http://www.phpmyadmin.net

  • What can phpMyAdmin do?

    • Create and drop databases and tables.

    • Work with multiple MySQL servers.

    • Manage users and privileges.

    • Export table data.

    • Execute any SQL statement.

    • 42 different languages.

    • And more.

  • Create Database

    19

  • Create Table

    20

  • Table Specs

    21

  • Table Created

    22

  • Outline

    • PHP Loops

    • PHPMyAdmin

    • Introducing SQL

    • Connecting Database from PHP

    • Exercises

    23

  • Introducing SQL (Structured Query Language)

    • SQL is a data definition language (DDL)

    • CREATE DATABASE `CISC492`

    • CREATE TABLE ‘Students’(

    Student_Number varchar(10),

    First_Name varchar(20),

    Last_Name varchar(20),

    Email varchar(30),

    Mark FLOAT)

    • DROP TABLE ’Students’

    • DROP DATABASE ’CISC492’

    Why not INT?

  • Introducing SQL

    • SQL is also a data manipulation language (DML)

    • INSERT INTO Students

    VALUES (`05771234`, `Test`, `Example`,

    `[email protected]`, `89`)

    • SELECT * FROM Students

    WHERE `Mark` BETWEEN 85 and 95

    ORDER BY `Mark` DESC

    • UPDATE Students SET Email = ‘[email protected]

    WHERE Student_Number = ‘05771234’

    • DELETE FROM Students

    WHERE `Student_Number` = ‘05771234’

  • Outline

    • PHP Loops

    • PHPMyAdmin

    • Introducing SQL

    • Connecting Database from PHP

    • Exercises

    26

  • Connecting Database from PHP

    1) Connecting MySQL

    2) Sending & Executing Query

    3) Fetching Data

    27

  • 1) Connecting MySQL • mysql_connect – function to connect to MySQL

    server

    – Returns database link identifier if successful

    • mysql_select_db – function to select a particular

    database from MySQL server

    – Returns TRUE if successful

    28

    $dblink = mysql_connect("local

    host", "root", "rootpass");

    mysql_select_db("mydb", $dblink);

    Password

    Database link

    identifier

    Server name

    or IP Address Username

  • 2) Sending & Executing Query • mysql_query ($query, $dblink) – executes query

    on database.

    – $query is string – the query to be executed

    – $dblink is the “database link identifier” previously returned from mysql_connect

    • The returned result depends on the query

    – If query is select, it returns a resource (result set) on successful or false on error.

    – If query is insert, update, delete, it returns true on successful or false on error.

    • The link parameter $dblink can be omitted if working with only one database throughout the script.

    29

    mysql_query("select * from students", $dblink);

  • 3) Fetching Data

    • mysql_fetch_assoc – returns associative

    array containing the current row in result

    and moved the pointer to the next one

    – The field names are keys in the array

    – Returns false if no more rows

    30

    $result = mysql_query("select * from students")

    or die(mysql_error());

    while ( $row = mysql_fetch_assoc($result) )

    echo "Student Number: ".$row['Student_Number'].

    " Student Mark: ".$row['Mark']."
    ";

    On error, display

    error message

    Assignment, not

    comparison,

    operator

  • Inserting Data & Number of Rows

    31

    $result = mysql_query (“INSERT INTO Students

    VALUES (`05771234`, `Test`, `Example`,

    `[email protected]`, `89`”) or die(mysql_error());

    • mysql_num_rows ($result) –

    returns the number of rows in a result set

    $result = mysql_query ("select * from

    students");

    $count = mysql_num_rows($result);

    echo “Total Number of Students is: $count”;

  • Exercise #3

    32

    Ex1_Insert.html

    Insert.php

  • Exercise #4

    33

    Ex1_Insert.html

    Show_Students.php

    Descending Order

  • Functions (MySQL)

    Category Example of functions

    Aggregate MySQL: SUM, AVG, MAX, MIN, COUNT

    Mathematical MySQL: SIN, COS, TAN, TRUNCATE, ROUND

    Text MySQL: LEFT, RIGHT, SUBSTRING, LENGTH, LOWER, UPPER, LOCATE, REPLACE

    Logical MySQL: IF, IFNULL

    Conversion MySQL: FORMAT, CONVERT, DATEF_ORMAT, STR_TO_DATE

    Date MySQL: CURDATE, DATEFORMAT, DAYOFMONTH, DAYOFWEEK, DAYNAME, MONTH, MONTHNAME, DATEDIFF, DATE_SUB

    Time MySQL: CURTIME, HOUR, MINUTE, SECOND, TIMEDIFF

  • Functions (PHP)

    Category Example of functions

    Aggregate

    Mathematical PHP: Sin, Cos, Tan, Floor, Round

    Text PHP: SubStr, StrLen, StrToUpper, StrToLower, StrPos, SubStr_Replace

    Logical PHP: If, While, For, Foreach, Switch

    Conversion PHP: StrToTime

    Date PHP: GetDate, Date

    Time PHP: GetTimeOfDay, StrFTime

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