Global findByRecId() function  

AX 2012 relies heavily on foreign key relations for its table relations. A consequence of this change is that now developers will be accessing tables using recIds rather than using any other primary key, which was the norm before. So far so good. So what’s the problem, you may ask.
One example I found in an excellent blog post.

http://www.doens.be/2009/07/select-a-record-from-a-table-when-you-only-have-the-tableid/

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Now when you need to access a record buffer in a table MyTable using record id, instead of writing it as MyTable::findByRecId(_recId), you can use findByRecId(tableNum(MyTable), _recId)