Skip to main content

PHP Functions for Retrieving Metadata

The most complete way to retrieve metadata is by using a SELECT statement against the
INFORMATION_SCHEMA database in the MySQL server. However, there are times that is overkill for
the data needing to be collected for a PHP application. With that said, PHP offers multiple functions that
provide methods for retrieving a small amount of metadata about the data in the MySQL server.

Database Metadata

The mysql_list_dbs() function retrieves the name of all the databases found on the server that are
accessible by the user requesting the information:

<?php
// Load variables used in mysql_connect and connect to server
include "connect_info.php";
$linkID1 = mysql_connect($dbhost,$dbuser,$dbpass) or
die("Could not connect to MySQL server");
// Retrieve the names of the databases accessible by the user
$schema_results = mysql_list_dbs($linkID1);
print "The databases available to the root user are:<br>\n";
while (list($schema) = mysql_fetch_row($schema_results)) {
print "$schema <br>\n";
}
// mysql_db_name() also displays the databases
print "The databases available to the root user are:<br>\n";
for ($count=0; $count < mysql_num_rows($schema_results); $count++) {
print mysql_db_name($schema_results,$count)."<br>\n";
}
?>

Table Metadata

The mysql_list_tables()function retrieves the name of all the tables found in the database identified that are
accessible by the user requesting the information:

<?php
// Load variables used in mysql_connect and connect to server
include "connect_info.php";
$linkID1 = mysql_connect($dbhost,$dbuser,$dbpass) or
die("Could not connect to MySQL server");
// List world database tables accessible by the user
$table_results = mysql_list_tables('world',$linkID1);
print "The world database tables available to the root user are:<br>\n";
while (list($table) = mysql_fetch_row($table_results)) {
print "$table <br>\n";
}
// mysql_tablename() also displays the world database tables retrieved
print "The world database tables available to the root user are:<br>\n";
for ($count=0; $count < mysql_num_rows($table_results); $count++) {
print mysql_tablename($table_results,$count)."<br>\n";
}
?>
Labels:

Comments

Post a Comment

Popular posts from this blog

PHP INTRODUCTION

                     PHP  (recursive acronym for  PHP: Hypertext Preprocessor ) is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. PHP stands for  P HP:  H ypertext  P reprocessor PHP is a server-side scripting language, like ASP PHP scripts are executed on the server PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.) PHP is an open source software PHP is free to download and use Why PHP? PHP runs on different platforms (Windows, Linux, Unix, etc.) PHP is compatible with almost all servers used today (Apache, IIS, etc.) PHP is FREE to download from the official PHP resource:  www.php.net PHP is easy to learn and runs efficiently on the server side What can PHP do? Anything. PHP is mainly focused on server-side scripting, so you can...
6 comments
Read more

SQL Joins

1. Login in to the mysql client using the login name and password provided by your instructor (if not already logged in). 2. View the existing databases that the MySQL Server is maintaining. SHOW DATABASES; 3. Utilize the photo_album database. USE photo_album; ---- If Need be, recreate the database and load the SQL data in that will be used for this lab CREATE DATABASE photo_album; SOURCE /tmp/photo_album.sql; 4. Query the database to display the active primary customer (email, first and last name) and all the associated active login names associated with that customer. SELECT customers.email_customer, customers.fname, customers.lname, logins.login_name  FROM customers, logins WHERE customers.email_customer = logins.email_customer  AND customers.active_customer = 'True'  AND logins.active_login = 'True';
Post a Comment
Read more

Data Encryption

Data encryption is the process of scrambling stored or transmitted information so that it is unintelligible until it is unscrambled by the intended recipient. The intended recipient can then decode (or decrypt) the information. PHP offers multiple means to make this happen. However, none of these solutions are very effective without the applications running on secure servers and connections. The following are a list of the more common encryption functions in PHP: • md5() - MD5 is a third-party hash algorithm that PHP can use to create a digital fingerprint of a piece of data. It is next to impossible to (efficiently) recover the original text when a piece of data has been encrypted with the md5 hash algorithm. It is also vastly unlikely that any different text string will create an identical hash - a 'hash collision'. These properties make hashes ideally suited for storing an application's passwords because although an attacker may compromise a part of the system...
2 comments
Read more