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I am trying to get a better general understanding of how ArcGIS works with MS Access when using a personal geodatabase. If I create a new pgdb and then import a very simple shapefile and finally look at the result through Windows explorer (rather than ArcCat), the only visible item from the pgdb creation process is one mdb file. Opening the mdb file in Access shows there are 11 tables (in the case of a shp file that had one point).

Generally, I can find very little documentation aboutlooking at a pgdb through Access, and if there is any sense in doing so (even if it is just for the benefit of trying to find out how it all works). Most resources about pgdb design don't go say too much compared the the other two recommended gdb alternatives. However, Access is still extremely popular, so I think there is some benefit to looking at the topic in more detail.

So is it possible to know how the mdb tables that ArcGIS creates are related, or are the relations defined by files that neither Access nor Windows can see? Is it possible to know how ArcGIS uses these tables to provide the "spatial" component to Access? Is it ever benefitial to use MS Access to work with a shp file stored as a pgdb? Or is this all futile because pgdb technology is proprietary and no detailed publicly available knowledge exists?

Any insight/links that answer the above and related types of questions would be appreciated.

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I've done simple queries against the attribute tables within PGDBs via Access, but would be very, very careful doing anything update related in one. Also, I have not found a way to access a FGDB outside of Catalog or ArcMap. –  user19052 Jun 12 '13 at 19:04
    
The File Geodatabase API lets you access a FGDB from a variety of contexts, including in GDAL which provides access for many open source GIS environments. –  scw Jun 12 '13 at 19:10
    
Can you extend your answer to address the specifics of the question? For example, how did you do the queries? What are the considerations that match the original posters requirements? –  BradHards Jun 12 '13 at 21:49
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1 Answer

up vote 3 down vote accepted

Esri's online help (see two links below as examples) discourages users from opening Personal Geodatabases stored in Microsoft Access using Access so I think your phrase "futile because pgdb technology is proprietary and no detailed publicly available knowledge exists" probably sums it up.

http://support.esri.com/es/knowledgebase/techarticles/detail/31599

http://support.esri.com/es/knowledgebase/techarticles/detail/30770

Personally, I never use Personal Geodatabases because shapefiles are easier to work with when you are aiming for simplicity, and File Geodatabases provide much more functionality and better performance.

If you are considering migration from Personal to File Geodatabases then this page from the online help may be useful.

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I'd agree with that. If you try to play around with the pGDB in Access the chances are that you'll break something. Better to use the file geodatabase API if you need to make changes outside of ArcCatalog/ArcMap. –  Stephen Lead Jul 30 '12 at 0:25
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I have been recklessly working with attribute data of key GIS files using MS Access, finding it much easier to work with for basic updating and reporting than ArcMap. Just don't mess with the GDB-prefixed tables which are automatically maintained by ArcMap. –  ako Jul 30 '12 at 2:17
    
I had a feeling it was not possible to know much. I'm still sort of with AkselO, there are so many things that are easier to do in Access (or Excel), related to updating attribute tables that do not rely on spatial queries, just sorts. I have never run into problems doing that, and sometimes the writing the pythonscript coding that would do the equivalent seems really round-about, and takes much longer. I dont know if it would be proper to say that the scripting method is more elegant, but I guess its more "proper"? –  youzer Jul 30 '12 at 18:18
    
Sometimes, you need to get a project finished for a deadline, and using Access can be a reasonable method. Just be sure to have a backup of your geodatabase before you start messing around "under the hood". Spoken from painful experience... –  Stephen Lead Jul 31 '12 at 6:34
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