I'm transforming a number of geographic tables from one MCD to another, so I'm using FME (I'm new to FME). I can map 80% of my fields with out any problem (MCD_A.fld_1 = MCD_B.fld_1) but in the in the second MCD I need to generate a new PK based on a concatenation of a string and a three digit increment something like 'BBBSYN_'||Increm.

I've tried generating the value directly in the FME writer (Feature Type -> User Attributes -> Value -> text Editor (see below) using @Count() - but this only generates simple increments '1','2','3' - I need '001', '002' etc. Also I already use @Count in another field and FME seems to confuse them both, i.e. in fld_1 and fld_2 of the same feature, count results in fld_1 = 1 and fld_2 = 2, not ideal.

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I've looked through the safe website and the youtube channel - which is full of useful stuff but it's like finding a needle in a haystack - I also found this on SE : How to create autoincrementing primary key with dynamic writer in FME

Which looked like it would solve at least part of the problem - but it's a couple of years old and I don't have same options available in my feature type dialog box (I can't set type to identity or index to primary key for example) - I'm using FME 2019 and this post is over two years old so i'm guessing they're not using FME 2019...

This is probably incredibly easy (it really should be...), but I can't find the right function ?

2 Answers 2


Congrats on getting this going. Yes, the @Count() function can take an optional “counter name” argument so that you can insulate one @Count invocation from another...should you want to.

But another way is to assign counts earlier and stash into an attribute. However, it seems that your line here:


Has an extra set of () on it — _count is an attribute and shouldn’t have () after it.


Above is what I think you’re looking for. Now that I fix that, I think the original actually had unbalanced () too. Probably just a typo but worth noting here in case future generations come looking.


OK so I found an answer on the FME forum in the end and I thought I'd share it here:

Basically in the field type dialog box in the field value I added:


This will left-pad the count with zeroes to 3 characters. To distinguish this count from previous count I just added 1 into the Count parameter ('Count(1)'). But in the end used a Counter to generate my numbers separately and just recovered the value, like below:



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