Obligations

An obligation is defined as a juridical necessity to give, to do or not to do. Its requisites are the following:

1.) Juridical/legal title

2.) Active subject (obligee/creditor)

3.) Passive subject (debtor/obligor)

4.) Fact, service or prestation that constitutes the obligation's object

The object must be legal, physically and juridically possible, determinate/determinable and must have a possible money equivalent. The sources of obligations are law, contracts, quasi-contracts, delicts (crimes) and quasi-delicts. 

Quasi-contracts are juridical relations coming from lawful, voluntary and unilateral acts based on the principle of the prevention of unjust enrichment: that no one can be unjustly benefited or enriched at another's expense. there are 2 kinds: Negotiorum gestio, when somebody voluntarily takes charge of the management of the property or business of another without the latter's authority; and, Solutio indebiti, which happens when somebody unduly delivers a thing by mistake to another person who doesn't have the right to demand it.

Nature of Obligations

1.) Personal -obligations either to do (positive) or not to do (negative)

2.) Real -obligations to give something that is either particularly designated/physically segregated from all others of the same class (specific/determinate) or designated merely by its class/genus (generic)

If the real obligation is specific/determinate, the creditor/obligee can compel specific perfomance, demand damages exclusive of or in addition to specific performance and is entitled to the fruits (products) and interest from the time the obligation to deliver arises. If generic, the creditor/obligee can ask for the performance of the obligation, ask that it be complied with at the debtor's/obligor's expense and demand damages in case of a breach.

For an obligor/debtor, if the real obligation is specific/determinate, he is required to render specific performance, take care of the thing with the diligence of a good father of a family (ordinary diligence,) deliver all accessions and accessories of the thing (even if not mentioned) and pay damages in case of breach of the obligation due to delay, fraud, negligence or contravening the obligation's tenor. If the real obligation is generic, he must deliver the thing of the same quality (neither superior nor inferior) and pay damages in case of fraud, delay, negligence or contravention of the obligation's tenor.

Breach

1.) Voluntary -debtor/obligor is guilty of default/delay (mora,) fraud (dolo,) negligence (culpa,) or contravention of the obligation's tenor in the performance of the obligation. He's liable for damages.

2.) Involuntary -debtor/obligor isn't able to comply with his obligation because of a fortuitous event. He's not liable for damages

Effects of a Breach on Personal Obligations

If the personal obligation is negative, the creditor can ask for damages and have the obligation undone at the obligor's/debtor's expense (Art 1168, Civil Code.) These remedies aren't available if 1.) the effects of the forbidden act are definite in character; or 2.) if it is physically or legally impossible to undo because of the nature of the act itself, a provision of law or because of the conflicting rights of 3rd persons. In either case, the remedy is to ask for damages. 

If it's positive, the creditor can have the obligation performed at the debtor's/creditor's expense, ask that what was done poorly be undone and recover damages because of the breach of obligation (Art.1167, Civil Code.)