CODIS has been heavily mythologized in crime scene shows. It is treated as a be-all, end-all that can pinpoint with exacting accuracy who was where, when.
This is a bit of an exaggeration. CODIS is not an all-seeing eye. It is a database of DNA samples, and out of all the DNA in a sample, it only keeps track of a few loci or points. It can indicate if someone is a parent/sibling, if someone is a cousin, or if someone is a match for those few loci. It consists of samples from convicts and cold cases, amongst others. It is certainly far from exhaustive in its catalog.
DNA is also not always all it's cracked up to be. For one thing, you can't get DNA from hair samples, unless the follicle or skin tissue is present on it. Second, heat makes DNA decay. If the site or the subject is burned after the incident, the DNA traces are also likely to be lost. Third, DNA can only be obtained if the sample of tissue from the scene is significant enough to undergo PCR or a polymerase chain reaction process - which multiplies what little was obtained into a quantity sufficient for processing.
Also, DNA analysis itself is not all fancy 3-D models with nice lighting effects a la "Bones". Most of it is looking at long readouts of peaks and troughs and little lines with numbers attached. It is fun, highly technical work, but definitely not very fancy on the GUI side of things (though I'm sure many geneticists would be excited if their interfaces enabled them to channel Tony Stark).
There are plenty of fun videos online that go into further detail about genetics and how genes function. My personal favorite are Khan Academy and CrashCourse Biology (I know, I'm basic).