When fields lists don't work as expected

Did you know that a field list in a single-record select-statement is not always beneficial in comparison to a select firstonly * from...  (or a static find-method)?

The thing is, when a where-clause matches a unique index (in AX 2009 – a primary index), the AOS may find the complete record in the cache and return it. And if this is the very first call, it will pull the whole record anyway, in order to be able to cache it. This may be proved by debugging.

So please use find-methods where possible, because they are easier to read and maintain. And remember: a while select with a nested find-method call may actually perform better than a join – thanks to caching. Therefore do measure performance to confirm that your select-statement is the most optimal one.

Table extension framework

There is a great article on how to use the table extension framework in AX 2012.

Keep in mind that if the parent table's primary key is not RecId-based, but the table has CreateRecIdIndex property set to Yes, then the relation on step #1 should be created based on "Single field AlternateKey based"; otherwise the new feld will potentially have wrong type, and it will not be possible to use it in the SysExtensionSerializerExtensionMap map.

And remember to add a DeleteAction to the parent table.