CCP 2003. An affidavit is a written declaration under oath, made without notice to the adverse party.
CCP 2009. An affidavit may be used to verify a pleading or a paper in a special proceeding, to prove the service of a summons, notice, or other paper in an action or special proceeding, to obtain a provisional remedy, the examination of a witness, or a stay of proceedings, and in uncontested proceedings to establish a record of birth, or upon a motion, and in any other case expressly permitted by statute.