This document discusses PHP functions for creating, reading, updating, and deleting (CRUD) data from a MySQL database. It explains how mysql_connect() is used to connect to the database and select a database using mysql_select_db(). It also covers how mysql_query() converts SQL statements into PHP code and how mysql_fetch_array() fetches query results row by row. The document recommends including connection code in a separate file and using mysql_num_rows() to count the number of rows returned.

1. hasen@microcis.net July 23, 2013Hassen poreya
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CRUD
Create, Read, Update, Delete

2. Requirements
 Choice of DBMS - MySQL
 Database model (ER - Schema)
 GUI – Application program

3. Functions may be used in CRUD
 mysql_connect()
 mysql_select_db()
 include()
 mysql_query()
 mysql_fetch_array()
 mysql_num_rows()

4. mysql_connect()
 mysql_connect()is designed to handle the
connection.
 You can use this function internally or you can
include it from an external source.
 This function takes 3 arguments by default.
 host, username, password
mysql_connect("localhost","admin",
“admin");

5. mysql_connect()
 To check whether the connection is established or
not we store this function into a variable and check
it with IF statement.
<?php
$con=mysql_connect("localhost","admin","admin");
if(!$con){
die('Could not connect: ' . mysql_error());
}
?>
 You can use this piece of code anywhere in your
code anytime, but that’s might be used several
times. Then you can put your code in a separate file

6. mysql_connect() In a Separated File
 You code up your connection and db selection into
a separate file, then you include that file into the
main file. Ex: connect.php contains the connection.
<?php
....
include („connect.php‟);
....
?>

7. mysqlSelect_db()
 Once you have successfully connected to My SQL,
then you must chose a database to work on.
 Another PHP fucnction is used to select a database
from database server.
mysql_select_db(“users”);

8. Query Conversion
 We have SELECT and INSERT queries in Mysql
and simply use them during inserting and
retrieving. BUT if we want to use them with PHP
we must convert them into PHP code.
 This conversion is done by a built-in PHP function
called mysql_query()
mysql_query ("INSERT INTO users (username,
password) VALUES ('$uname', '$pword')")

9. Query Conversion
mysql_query("SELECT * FROM users
WHERE username= „ahmad'");
 When we use SELECT statement, each time it returns
one row of a table.
 To store the returned data into a variable we must
fetch them one by one and store them.
 This can be done by a function called
 mysql_fetch_array()

10. Query Conversion
$query=mysql_query("SELECT * FROM users
WHERE username= „ahmad'");
 $result= mysql_fetch_array($query)
QueryFetch row by row from queryRecord set

11. mysql_num_rows()
 The mysql_num_rows() function returns the
number of rows in a record set.
 This function returns FALSE on failure.

12. Let’s do the practice

13. hasen@microcis.net July 23, 2013Hassen poreya
Trainer, Cresco Solution
Any Questions!
Afghanistan Workforce
Development Program