science-ation/db/db.update.173.php

<?php
function db_update_173_pre(){
}

/****
This script takes all Latin1 character encoding in the database and converts it to UTF-8
****/
function db_update_173_post(){

	// patch the committees_link table
	mysql_query("ALTER TABLE `committees_link` ADD `id` INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY");

	// loop through every table in the database
	$data = mysql_query("SHOW TABLES");
	$fields = array();
	$keys = array();
	$allTables = array();
	while($tableInfo = mysql_fetch_array($data)){
		$tableName = $tableInfo[0];
		$allTables[] = $tableName;

		// loop through every field in the table
		$query = mysql_query("DESCRIBE " . $tableName);
		$keys[$tableName] = array();
		while($rowInfo = mysql_fetch_array($query)){

			// find out if this field is a varchar, char, text, or tinytext field
			if(preg_match('/.*char.*|.*text.*/', $rowInfo['Type'])){
				// it does, so this field needs to be converted
				if(!array_key_exists($tableName, $fields)){
					$fields[$tableName] = array();
				}
				$fields[$tableName][] = $rowInfo['Field'];
			}
			if($rowInfo['Key'] == 'PRI'){
				$keys[$tableName][] = $rowInfo['Field'];
			}
		}
	}

	/* The array "fields" now contains the names of all fields in the database that
	need to be converted (and only those that need to be converted), stored in this format:

	[table1] => Array
	    (
		[0] => fieldname1
		[1] => fieldname2
		...
	    )

	[table2] => Array
	    (
		[0] => fieldname3
		[1] => fieldname4
		[2] => fieldname5
		...
	    )
	 ...

	Now we need to run through those tables one at a time and convert them
	*/
	$errorTally = 0;
	echo "Updating records:\n";
	foreach($fields as $tableName => $fieldSet){
		// build the query that gives us the field values we need to update in this table, as well as the primary keys
		$query = "SELECT `" . implode('`, `', $fieldSet) . '`';
		for($n = 0; $n < count($keys[$tableName]); $n++){
			$query .= ", `" . $keys[$tableName][$n] . "` AS __KEYFIELD_" . ($n + 1) . "__";
		}
		$query .= " FROM $tableName";

		// fetch all of those values
		$updates = array();
		$data = mysql_query($query);
		while($record = mysql_fetch_array($data)){
			$updates[] = $record;
		}

		// now re-insert those values into the table
		foreach($updates as $update){
			$query = "UPDATE $tableName SET";
			$useComma = false;
			foreach($fieldSet as $fieldName){
				$fieldValue = $update[$fieldName];
				if($useComma){
					$query .= ",";
				}else{
					$useComma = true;
				}
				$newValue = mb_convert_encoding($fieldValue, "UTF-8", "iso-8859-1");
				$query .= sprintf(" `%s` = '%s'", $fieldName, mysql_real_escape_string($newValue));
			}
			$query .= " WHERE ";
			for($n = 0; $n < count($keys[$tableName]); $n++){
				if($n > 0) $query .= " AND ";
				$query .= "`" . $keys[$tableName][$n] . "` = '" . mysql_real_escape_string($update["__KEYFIELD_" . ($n + 1) . "__"]) . "'";
			}
			$success = mysql_query($query);
			if($success) echo '.';
			else{
				echo "\nFailed to execute query: $query\n";
				$errorTally ++;
			}
		}
		unset($updates);
	}
	echo "\nComplete with $errorTally failed queries.\n";

	// now drop the id column that we added to the committees_link table
	$query = "ALTER TABLE `committees_link` DROP `id`";
	mysql_query($query);
}