After the sequence diagram are made the sequence methods become code, before writing some code that would alter database records I would like to know how to detect if a sequence is doing the job without damaging some other part's of the system, what comes to my mind is that there must be a way to relate the sequences to something so that it would be easy to analyze by having a high-level document to keep track of.
I would recommend drawing a class diagram or a component diagram showing the classes of objects that participate in your sequence diagrams.
- The messages in your sequence diagrams should match the operations defined on the classes.
- The relationships among the classes should reflect which classes interact with which other classes. For example, if method X of class A calls method Y of class B, then you could draw a dependency arrow from A to B in the class diagram.
If you have complex interactions and you want to divide such a complex interaction over multiple sequence diagrams, you could use an interaction overview diagram. This resembles an activity diagram, where each action is a (reference to a) sequence diagram or other kind of interaction diagram. The following image is copied from the UML 2.5 specification.