If I use e.g. StaticFW or OptimizeFW in a larger workflow, the results of the calculations will be put into the database. If I need some output later on in another Firework, I want to put it in the fw_spec, which I can then pass on to the next Firework.
My question is if I should use database queries if I wish to later use some output value like the total energy in another Firework? If I would like to do that, how would I properly identify the correct calculation? Using code similar to the tutorial about the MgO bandstructure I think that I might get problems if I have several structures for the same compound. Should I pass the firework ID with a powerup? Can you recommend some documentation about MongoDB queries, especially for the VaspCalcDb case?
Intuitively I would rather write a new Firework that copies the output files using PassCalcLocs and then just parsed the OUTCAR using Outcar from from pymatgen.io.vasp.outputs. However, using the database seems very powerful, and I want to use best practice from the beginning if possible.
Thanks a lot, Michael