The two easy ways to do this with Postgres. One is to specify the ID col. as serial type, which will cause it to be auto-incrementing (i.e. when you insert a row, it will automagically get a new, unique val in the serial col).

Additionally, you can use a postgres sequence to keep track of the ID, and query it with postgres's nextval function whenever you need a new value: 

  my $sth=$dbh->prepare("select nextval(?)");
  $sth->execute("seq_name");
  my $id=$sth->fetchrow();
  $sth->finish();

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Of coruse, you can also do this the old-school way too (but its less efficient to do it this way):

Have a table to store the last assigned ID. When you need an ID, lock that table, read the value out of it, write the value+1 back to the table, and then unlock it.

In reply to Re: Unique ID by lhoward
in thread Unique ID by nlafferty

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