What is the consequence of a pleading of guilty in a criminal proceeding?

In a criminal proceeding the entry of a guilty plea is more than a confession. It is itself a conviction leaving nothing to be done but give judgment and determine punishment. (Boykin v. Alabama (1969) 395 U.S. 238, 242, 89 S.Ct. 1709, 1711, 23 L.Ed.2d 274.) That consequence demands a showing on the record that the plea is voluntary and not the product of "ignorance, incomprehension, coercion, terror, inducements [or] subtle or blatant threats," and that the guilty pleading defendant knowingly waived the constitutional rights to which he is entitled in a criminal trial. (Id., at pp. 242-243, 89 S.Ct. at p. 1712. See also, In re Ibarra (1983) 34 Cal.3d 277, 285-286, 193 Cal.Rptr. 538, 666 P.2d 980; In re Tahl (1969) 1 Cal.3d 122, 81 Cal.Rptr. 577, 460 P.2d 449.) So, too, the execution of an agreement for entry of a judgment of paternity leaves nothing to be done but entry of that judgment and of the order for support.