Common law is commonly defined as jurisprudence and it is of 2 types – one in which the decisions made are existing legislation in which there are no legislation and another where the court may require the current law and establish new definitions and divisions.
The legislative regulations can be enacted by the various departments of a country. Therefore, there's many laws enacted by state and federal governments, laws enacted by cities and municipalities, all of which have the force of law.
Ex. If you check the weather and it says its supposed to rain in about 15 minutes, you would want a jacket or even an umbrella right? It would be smart to bring both of those items along with you.