Databases

Up until now, I've pretty much ignored databases in the development of Angela. Even if you have thousands of templates, the table structure is simple enough that a python dict will do the job in finding what you need. With entities, things get more complex. I see two separate issues:

1 - Templates are static and need not be persistent across resets. We can just re-read from the XML file on server start. Entities do get changed from their initial state and do need to be saved to a DB. That state should constantly be kept updated.

2 - Transactional data regarding entity updates should probably stored in its own DB table (or tables) along with metadata about the parent action, subject agent, controllers, etc. This way, if you have crystal reports or something similar - or know how to wield pivot tables in Excel - you can extract daily reports (good for GMs to peruse; especially for identifying exploits) or data mine the world to see what is actually happening

Both of these scenarios are shown in the sequence diagram in EntityUpdate.pdf. The general idea is that whenever an entity change is made, the changing method drops a fire and forget message into two queue objects. One updates the persistent database version of the entity repo, which also contains persistent entities that are not currently logged in. The other goes to the queue for tracking changes.

I have an interesting quandary with entities. Specifically, entities can freely take other entities in as members. Currently, if I want to see if an orc is carrying a goldCoin object, I'd use the getMemberEntiesByType() method on the orc (he is an Entity object). If I wanted simply to know whether he had a gold coin directly in his endocontainer inventory, I'd iterate over the things in his inventory (i.e. member entities) and take a peek at their parent meme IDs. Now if we set drillDown = True, we are telling getMemberEntiesByType() to look inside the inventories of all of those objects and so forth. Can this be done better and faster using SQL trickery? If this is so, how should we do it?