searching an array of strings in mysql - php

Question

i have an array of strings and i need to search whether the strings of the array exits in database or not. i am using following query:
foreach($array as $s)
{
if(preg_match('/^(\bpho)\w+\b$/', $s))
{
$query="select * from dictionary where words REGEXP '^".$s."$'";
$result=$db->query($query) or die($db->error);
if($result)
{
$count += $result->num_rows;
}
}
}
but this query taking long time to execute. PLease provide a solution to reduce the searching time

Answer 1

I don't think your problem here is about your code. I think you should optimize your database.
I'm not very good at it but I think you could add indexes in your database to speed up the research

Answer 2

Combine all the search strings into a single regular expression using alternation.
$searches = array();
foreach ($array as $s) {
if (preg_match('/^(\bpho)\w+\b$/', $s)) {
$searches[] = "($s)";
}
}
$regexp = '^(' . implode('|', $searches) . ')$';
$query="select 1 from dictionary where words REGEXP '$regexp'";
$result=$db->query($query) or die($db->error);
$count = $result->num_rows;
If $array doesn't contain regular expressions, you don't need to use the SQL REGEXP operator. You can use IN:
$searches = array();
foreach ($array as $s) {
if (preg_match('/^(\bpho)\w+\b$/', $s)) {
$searches[] = "'$s'";
}
}
$in_list = implode(',', $searches);
$query="select 1 from dictionary where words IN ($in_list)";
$result=$db->query($query) or die($db->error);
$count = $result->num_rows;

Answer 3

Searching the whole database is a large job, I think a better way is you can cache some parts of the database, and than search in the cache. Redis is very good.

Answer 4

Modify your query so that is doesn't select all table columns - that is a waste of resources. Instead, just let the database count the number of rows containing the search query and return back only a single answer (matches):
$query = "SELECT COUNT(id) AS matches FROM dictionary WHERE words REGEXP '^".$s."$'";
How are you indexing your database? If your words column is not indexed properly, then your regexp would take a long time. Examine your database structure and potentially add indexing to the words column.
P.S. And don't forget to fetch the matches column instead of using num_rows