Check whether data is at table - php

Question

I asked something about in_array() and I already got that working. But now I have a different problem:
I have a table that says which services are assigned to hosts: services_hosts(service_id, host_id).
How can I see if the service that is selected is already assigned to that host, also selected? Basically, I want to see if the specific line (service_id, host_id) already exists in that table.
EDIT:
The problem is that I want to compare in a separate file that has functions that connect to DB:
function addServiceToHost($service_name, $host_id)
{
$query = "INSERT INTO monitoring_hosts_services (service_id, host_id) values ((SELECT service_id FROM monitoring_services WHERE name = '".$service_name."'), '".$host_id."')";
$result = #pg_exec($this->conn, $query);
if ($row = pg_fetch_row($result))
{
"blabla error msg"
exit;
}
return $this->parseResultObj($result);
}

Answer 1

I might not unserstand your question correctly but would this do the trick:
SELECT * FROM ServerHostsTable WHERE service_id = '5' AND host_id = '8'

Answer 2

$query = ("SELECT * FROM ServerHostsTable WHERE service_id = '5' AND host_id = '8'")
if(mysql_num_rows($query)>0)
{
//the item is in the db
}
else
{
//not in the db
}
hope this helps

Answer 3

your question is not very clear, but from what I understand you want to test if a specific row is inserted into a database table. you could do this like this:
$result=mysql_query("SELECT service_id FROM services_hosts WHERE service_id=$theserviceid AND host=$thehostid");
if($row=mysql_fetch_row($result){
echo "already in the db";
} else {
echo "not in the db!";
}

Answer 4

I would run this query.
$sql = "SELECT COUNT(*) AS ret\n";
$sql.= "FROM services_hosts\n";
$sql.= "WHERE service_id = $service_id\n";
$sql.= "AND host_id = $host_id";
The result should be one row with one field (named ret):
0 - the service is not present on the host
1 - service is present on the host
enything else - there is a problem with table in database