Are FGDBs an extension of a different database engine under the hood?

Question

Are file geodatabases an extension of a different kind of database engine under the hood? For example, are FGDBs a customized version of an SQLite database?

I'm aware that FGDBs are proprietary and inaccessible outside of ArcObjects. But it would still be helpful to know what kind of database Esri might have started with when architecting FGDBs. I assume the core non-spatial database component wasn't built 100% from scratch.

Knowing what the original database was would help inform how we use SQL when writing SQL expressions on FGDBs in ArcGIS. Or even when writing database views on FGDBs*.

Thanks.

Bud · Answer

For what it's worth, the docs say this about the SQL syntax used by FGDBs:

SQL reference for query expressions used in ArcGIS

All SQL used by the file geodatabase is based on the SQL-92 standard.

That doesn't address the original question, but it does help clarify what kind of SQL the FGDB uses.

Related: SQL for reporting and analysis on file geodatabases

VinceAngelo · Answer

No, there is no "original database" for file geodatabase. It was created as a replacement for the Access-based "personal geodatabase" and as a lesser-complexity sibling of enterprise geodatabases. It is NOT based on any database (and if you look at the implentation, you can see the Esri VFILE lineage with INFO flair)..

- V

BTW: "inaccessible outside of ArcObjects" is not quite accurate, since the FileGDB API provides third-party access.

Bud · Answer

*I learned recently that it's possible to create a database view on an FGDB. Which is very interesting.
Create Database View (Data Management): “This tool is supported for databases, enterprise geodatabases, mobile geodatabases, and file geodatabases.”

* ETL & File Geodatabase Views
* Support query layers for file geodatabases
* Can't divide numbers in SQL in FGDB view:* BUG-000085841 The Create Database View tool does not accept the divide operator '/' in the view definition input field.
* Loss of division when creating a database view in a file geodatabase
* In relation to the original post:
If we knew what the underlying database was, then maybe we could determine if there is a workaround for the division issue. For example, is there a DIVIDE() function that could be used instead of the divide operator '/' ?