Civil liability, contractual liability, and unconventional have two branches. If there is a contract between two or more persons and one of them committed a breach of contract (failure to perform, delay in performing the obligation) to and to harm the other party is incomplete and should the contract have contractual liability for damages cope. Where does harm to another person without a contract exists between them or if there is a contract, Inflict losses not related to the contract, the talk of non-contractual liability.

About whether contractual and non-contractual obligations is two different legal system or single legal system form, there is disagreement among the lawyers: Some distinguish these two systems from each other. But others believe that because the purpose of civil liability is to compensate for losses, these two are the single legal system.