[liphp] (no subject)

[Venkatagiriyappa, Veena]

Hi,
I have a table proposal in postgresql databse which has a unique primary key
proposal_id
This is a varchar field but is kind of autoincrement field(indirectly).
every time user submits a proposal, the proposal_id needs to be generated. I
have problem in this part. My propoalid should be like:
x6a1,x6a2.....x6a20....etc

I tried with "SELECT max(proposalid) from proposal" but it works only till
x6a9 and after that it considers x6a10 as x6a1 for comparing the max value. 
I don't know how to take the last record from the table in order to generate
the next proposalid. I have an option to declare a global variable called
$lastpid and as and when the proposal record gets inserted into the proposal
table, store that value into $lastpid but for some reason this is not
working. the global variable is not retainign the value. 

The function generate goes like this:

function generate_proposalid()
{
    global $lastpid;
    $query = "select count(proposalid) from proposal";
    $result = pg_query($query);
    $row=pg_numrows($result);
    if($row>0)
    {
        $latestpid=$lastpid;
        /* Use the substring function to extract value after x6a (3 in case
of x6a3)
           from the proposalid */
        $latestpid = substr($latestpid,3);
        /* Increment the integer part */
        $latestpid++;
        /* Generate new proposalid by prefixing x6a to incremented value */
        $proposalid = "x6a" . $latestpid;
    }
    else
    {
        /* In case of first proposalid */
        $proposalid = 1;
        $proposalid = "x6a" . $proposalid;
    }
    return $proposalid;
}

Please tell me if there is any alternative. Value for $lastpid is being
stored in the called program after the value is returned from
generate_proposal function. Am I going wrong somewhere? I have been trying
with this problem since many days. Some times some logic works but fails in
specific condition.

Any help will be appreciated.