Re: Display realtime data As it changes in the databse - TK

[Gabriel Cooper]

Ramprasad A Padmanabhan wrote:

Voodoo Raja wrote:

Sorry for not posting it in the first place.

Will this sub.. chew memory if I run it a number of times.. or does 
it overwrite it.

sub read {
print "\nreading data";
$db = DBI->connect("DBI:mysql:$dbase:$hostname", $username, $password); 

as Ramprasad said, you should pass in your db connection if you use it 
in more than one function...

$query = $db->prepare("SELECT * FROM cash where f1 = '1002'"); 

Generally speaking, if you're selecting " * " then you're doing 
something wrong. You should only select exactly what you want from a 
database rather than "just give me it all and I'll figure it out later". 
Especially because--judging from the loop below--you don't appear to use 
anything in the db except the first field, but also because this method 
doesn't take into account changing database structure. Ramprasad 
suggested "select max($field1) from cash where $x = $y " but keep in 
mind you should do this using placeholders where any user input is 
involved to protect yourself from SQL injection attacks. =]

$query->execute;
$numrows = $query->rows;
while (@array = $query->fetchrow_array ) {
($field1, $field2, $field3, $field4, $field5, $field6, $field7, 
$field8, $field9, $field10,
$field11, $field12, $field13, $field14, $field15, $field16, $field17, 
$field18) = @array;}
$query->finish;
$db->disconnect; 

Don't disconnect yourself from the database in the middle of a while 
loop that's iterating through database query results!
Move finish and disconnect out of the loop.

print "\nf1 is $field1";
$lasttrans = "$field1";
$newtrans = ($lasttrans+1);
}
[...]


What you seem to be doing is not very clear.  Why are you running this 
loop
while (@array = $query->fetchrow_array ) {
($field1, $field2, $field3, $field4, $field5, $field6, $field7, 
$field8, $field9, $field10,
$field11, $field12, $field13, $field14, $field15, $field16, $field17, 
$field18) = @array;}

If you just want the last  transaction id  change the query
to "select max($field1) from cash where $x = $y ";
This will give you the last transaction id directly

BTW 1) Have you considered using an autoincrement field
2) Do not connect to the database in every function of yours .
Make one connection in the beginning and pass the handle to all 
functions.
3) And when you post a reply  to a newsgroup post your reply *at the 
bottom* avoid top posting

Ram







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