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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";
}
?>
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