UML stands for Unified Modeling Language, it is considered by many a standard language (no wonder why we use it in almost every programming class). It is mainly to have an overall view of what one is working with. Moreover, it also works to start making a documentation, this could apply to database since building a UML based on DB is to store data etc.
UML was created by the OMG. Yes, the OMG which means Object Management Group. UML didn’t saw the light until its 1.0 version came out in 1997. One thing to have into consideration is that although you work with programming UML shouldn’t be compared with python or anything related with programming (actual code).
You could use UML as a starting point. Making a UML for a clock that divides the subclasses and its components such as elements, behavior etc.
As mentioned before UML is mainly used for modeling and building the “end” product. See it as a blueprint that are used to build dry vans, houses and buildings. Some would even consider it a starting point and move from there. One thing people need to understand is that UML can be used for many things, not only programming. Take for instance a Zoo, you can classify the animals by reptiles, mammals etc. bigger classes that take a larger range of information.
What’s the verdict?
UML is used to create a starting point. It’s great to have a greater idea of what you are building and what you need to work with. In any case, not having all the elements is normal since UML also helps you to see what are you missing, what can you take out or modify. As history keeps moving more programming languages raised and it needs to be worked with a blueprint. UML is not only used for programming but also for companies such as zoo, mechanical store you name it.