2 kinds of public officer's duties

There are two kinds of duties exercised by public officers: the "duty owing to the public collectively" (the body politic), and the "duty owing to particular individuals, thus:
1. Of Duties to the Public. - The first of these classes embraces those officers whose duty is owing primarily to the public collectively --- to the body politic --- and not to any particular individual; who act for the public at large, and who are ordinarily paid out of the public treasury.

The officers whose duties fall wholly or partially within this class are numerous and the distinction will be readily recognized. Thus, the governor owes a duty to the public to see that the laws are properly executed, that fit and competent officials are appointed by him, that unworthy and ill-considered acts of the legislature do not receive his approval, but these, and many others of a like nature, are duties which he owes to the public at large and no one individual could single himself out and assert that they were duties owing to him alone. So, members of the legislature owe a duty to the public to pass only wise and proper laws, but no one person could pretend that the duty was owing to himself rather than to another. Highway commissioners owe a duty that they will be governed only by considerations of the public good in deciding upon the opening or closing of highways, but it is not a duty to any particular individual of the community.

These illustrations might be greatly extended, but it is believed that they are sufficient to define the general doctrine. (Vinzons-Chato v. Fortune Tobacco, G.R. No. 141309, December 23, 2008, citing Mechem, A Treatise on the Law of Public Offices and Officers, 1890, pp. 386-387)

2. Of Duties to Individuals. - The second class above referred to includes those who, while they owe to the public the general duty of a proper administration of their respective offices, yet become, by reason of their employment by a particular individual to do some act for him in an official capacity, under a special and particular obligation to him as an individual. They serve individuals chiefly and usually receive their compensation from fees paid by each individual who employs them.

A sheriff or constable in serving civil process for a private suitor, a recorder of deeds in recording the deed or mortgage of an individual, a clerk of court in entering up a private judgment, a notary public in protesting negotiable paper, an inspector of elections in passing upon the qualifications of an elector, each owes a general duty of official good conduct to the public, but he is also under a special duty to the particular individual concerned which gives the latter a peculiar interest in his due performance.(Vinzons-Chato v. Fortune Tobacco, G.R. No. 141309, December 23, 2008, citing Mechem, A Treatise on the Law of Public Offices and Officers, 1890, pp. 386-387)

In determining whether a public officer is liable for an improper performance or non-performance of a duty, it must first be determined which of the two classes of duties is involved. For, indeed, as the eminent Floyd R. Mechem instructs, "[t]he liability of a public officer to an individual or the public is based upon and is co-extensive with his duty to the individual or the public. If to the one or the other he owes no duty, to that one he can incur no liability."