[Zope] ZSQLMethod conditional insert

[Thomas Olsen]

Hi

This is probably an FAQ but I haven't been able to find and answer.

I need a counter for a certain CMFType and want to store the hits in a MySQL 
database not to fill up the ZODB. I've checked to two suggestions below but 
they both use two ZSQLMethods first to check if the URL is already in the 
table, then to do the actual update or insert.

http://www.zope.org/Members/element/Simple_SQL_Page_Counter
http://zopelabs.com/cookbook/991116439

I'd like to be able to do that just in one ZSQLMethod for efficiency but I 
cant seem to figure out a way of doing it.

The table is very simple:

CREATE TABLE mostread (
  path varchar(255) NOT NULL default '',
  num bigint(20) NOT NULL default '0',
  dt datetime NOT NULL default '0000-00-00 00:00:00',
  PRIMARY KEY  (path)
)

For now my ZSQLMethod get the argument "path" which is a relative URL and it 
looks like this:

  select @lastval:=num from mostread where <dtml-sqltest path type="string">
  <dtml-var sql_delimiter>
  update mostread set num=@lastval+1, dt=now() where <dtml-sqltest path 
type="string">;
  </dtml-if>

But that naturally only works if there is already a record containing "path". 
What I want to do is something like this (pseudo-code):

  select @lastval:=num from mostread where <dtml-sqltest path type="string">
  <dtml-var sql_delimiter>
  <dtml-if "sequence-length > 0">
    update mostread set num=@lastval+1, dt=now() where <dtml-sqltest path 
type="string">;
  <dtml-else>
    insert into mostread(path, num, dt)
      values(<dtml-sqlvar path type="string">, 1, now())
  </dtml-if>

Is there a way of doing this or should I just create that extra ZSQLMethod?

-- 
Med venlig hilsen

Thomas Olsen
http://www.headnet.dk