Layers in MS Dynamics AX

• The layer technology in Axapta is used to organize (keep track of) the objects of the standard package and the customizations made.
• There are eight standard layers. Each of these standard layers has a corresponding patch layer for a total of 16 layers
• The lower four layers are used for the standard package and are not accessible by partners or customers
• Partners and customers are each allocated two layers, along with the corresponding patch layers
• When logging on to an Axapta client, the current layer is choosen from the client's Axapta Configuration (which you can edit in Adiminstrator tools > Microsoft Dynamics <version> Configuration
• You cannot change a layer without restarting the client. All modifications made will be saved in the current layer.
• Your changes will be saved in the current layer. The modifications made to the top layer will always override the lower layer
• If you want to start all over, just delete the object in the current layer and you will be back where you started
• When a customer licenses the software, they receive access codes for the top two layers and are therefore excluded from directly modifying contents of the lower six layers. This prevents a customer from irrevocably changing the core code provided by Microsoft or their business partner
• And this does not prevent you from changing this code. When editing a standard object, Axapta copies part or the entire object from one of these lower layers into the current layer

The below figure consists of various Layer names and their purposes.



Figure: Layers overview




·         Each of the layers is stored in physical file with the naming AX<layer>.AOD. The filename for the sys layer is AXSYS.AOD. The layers are indexed in the file AXAPD.AOI

·         If deleted, the index file is built automatically at startup

·         If you have set the development option to show all layers at Tools | Options, all layers for an object will be shown in parentheses after the object name in the AOT

Tip:
You might end up in a situation where you cannot locate an object in the AOT, or other strange system behavior such as the AOT crashing when a certain object is accessed.
Then it might help to delete the index file and have it rebuild at startup