Component diagram dependency vs assembly

Question

I\'m having a hard time understanding the difference between dependency and assembly(ball and socket) in UML component diagram.

I googled a lot and only found this

Answer 1

A component is a piece of software. This is the class level (definition level). This piece of software may be installed on multiple machines, or maybe multiple instances may be running on the same machine. This is the instance level. If, in your case, each component is instantiated only once, then you only need one diagram, showing the instances. Otherwise, it would be good to have one diagram show the class level and one diagram show the instance level.

For example, there is a component called EmployeeProvider, which provides services to access an employee database. Suppose there is an instance running in the USA and one instance running in Europe. Suppose also that there is a report generator component, which only has one instance, which reads information from both employee databases. Below you can see two diagrams, one showing the class level (top) and one showing the instance level (bottom).