Too many joins in query

In Dynamics AX 2012, if you are running a query with too many joins you can get an error or warning message saying “The number of joins in the statement is XX.  This exceeds the maximum of 26.  Turn on exception for this warning to see the call stack.”


So what is this, and what can you do about it?

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Implementing checkpointing in long-running updates

Occasionally we need to run updates or inserts of large numbers of records, something which has this nasty habit of taking out locks that will prevent other sessions from updating or inserting in the same tables.  Also, if we terminate such an operation, we’ll have to start all over again from the beginning, wasting a lot of time.

Luckily, with Read Committed Snapshot Isolation which is supported by AX, readers will not be blocked by writers, but writes will still be blocked by other writes.  Once SQL Server escalates the row-level locks to table-level locks things start to go downhill rather quickly, and as we’re pretty much guaranteed not to have an outage window in which to run the update operation, someone is going to be on the phone soon.   Quite soon…

The solution is to break the operation into smaller transactions.

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Debugging .NET code called from Dynamics AX

From time to time it is necessary to develop custom .NET code and call it from Dynamics AX.  It could be that you already have the .NET code to do what you need and you don’t want to reimplement the functionality in X++, or what you are trying to do is too complex to do directly in X++.

One common situation is where you need to write a wrapper around some operating system functionality or web service to expose a much simpler API to AX.

This works, and AX has good support for calling .NET code through it’s .NET interop framework.  One thing that does become more complicated is debugging, but once you know how it is actually quite easy.

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How-to: Tree lookups in Dynamics AX reference group controls, part 4

This is something that keeps coming up on different projects, so I’d like to share how I usually do this.  There are some examples out there which try to describe a very generic solution which can be used in almost any case.  However, such solutions very quickly become very complex.  To keep things simple, I have tried to keep this example fairly specific but adaptable to a wide range of circumstances.  Specifically this example is using a fixed hierarchy structure with a fixed number of levels, each of which will be represented by a different table.

If you have not read the first 3 parts ( 1, 2, 3 ) of this tutorial yet, I recommend you do that first, to help with the understanding of this post, which explains how to automatically navigate to the currently selected item in the tree lookup.  This is something which is quite easy to do in a traditional lookup but requires a bit more work when dealing with trees.

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How-to: Tree lookups in Dynamics AX reference group controls, part 3

This is something that keeps coming up on different projects, so I’d like to share how I usually do this.  There are some examples out there which try to describe a very generic solution which can be used in almost any case.  However, such solutions very quickly become very complex.  To keep things simple, I have tried to keep this example fairly specific but adaptable to a wide range of circumstances.  Specifically this example is using a fixed hierarchy structure with a fixed number of levels, each of which will be represented by a different table.

Earlier, I have introduced the data model sitting behind the tree lookup, and last time I showed how to build the actual tree structure.

If you have not read these posts yet, I recommend you do that first, to help with the understanding of this post, which explains how to provide a more useful tree reference in the calling form.

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