Autoincrement a certain field of a certain template

[owzim]

Is there a neat an straightforward PW way of incrementing a value of a field other than getting all pages with that template an figuring out the highest value through a loop or something? 

In this case it should not be a regular auto increment but a number one higher than the highest of the already inserted pages.

[MatthewSchenker]

Greetings,

Interesting coincidence... I was just this morning trying to figure out a neat way to do this. In my case, I am building a site with property listings, and I want to auto-generate the listing numbers.

I was thinking of just tying into the page ID.

Would be interested in other ideas...

Thanks,

Matthew

[arjen]

$pages->count("selector") is supposed to use less overhead and therefore more efficient. 

[Soma]

Oh, another owzim question 

$val = $pages->find("template=mytempl, sort=-counter, limit=1")->first->counter + 1;

[owzim]

Oh, another owzim question 

$val = $pages->find("template=mytempl, sort=-counter, limit=1")->first->counter + 1;

Alrite, selectors ftw, thanks Soma.

[Harmster]

Are you using the field as a unique value? If so I woulnd't use these methods...

[owzim]

Are you using the field as a unique value? If so I woulnd't use these methods...

No, just as a value to be incremented.

[SteveB]

Sometimes I setup a table for counters...

 CREATE TABLE counters (
   count int(10) unsigned NOT NULL DEFAULT '0' ,
   name char(10) NOT NULL ,
   PRIMARY KEY (name)
 );

And a function like this:

function bumpCount($mysqli, $name){
    if($result = $mysqli->query("UPDATE counters SET count = LAST_INSERT_ID(count+1) WHERE name = \"$name\"")){
        $count = $mysqli->insert_id;
        if($count>0) return $count;    //normal
        if($result = $mysqli->query("INSERT INTO counters (count, name) VALUES (1, \"$name\")")) return 1;    //initialize new counter
    }
    return false;
}

And use it like this:

$mysqli = new mysqli('host', 'user', 'password', 'database');
echo 'The counter is: ' . bumpCount($mysqli, 'foo');

If anything goes wrong it returns false.

New counters are setup automatically when you use a new name. First number issued is 1.

The usual disclaimers about code examples apply.