California Code of Civil Procedure Section 2019

2019.  (a) Any party may obtain discovery by one or more of the
following methods:
   (1) Oral and written depositions.
   (2) Interrogatories to a party.
   (3) Inspections of documents, things, and places.
   (4) Physical and mental examinations.
   (5) Requests for admissions.
   (6) Simultaneous exchanges of expert trial witness information.
   (b) The court shall restrict the frequency or extent of use of
these discovery methods if it determines either of the following:
   (1) The discovery sought is unreasonably cumulative or
duplicative, or is obtainable from some other source that is more
convenient, less burdensome, or less expensive.
   (2) The selected method of discovery is unduly burdensome or
expensive, taking into account the needs of the case, the amount in
controversy, and the importance of the issues at stake in the
litigation.
   The court may make these determinations pursuant to a motion for a
protective order by a party or other affected person.  This motion
shall be accompanied by a declaration stating facts showing a good
faith attempt at an informal resolution of each issue presented by
the motion.
   The court shall impose a monetary sanction under Section 2023
against any party, person, or attorney who unsuccessfully makes or
opposes a motion for a protective order, unless it finds that the one
subject to the sanction acted with substantial justification or that
other circumstances make the imposition of the sanction unjust.
   (c) Unless there is a rule of the Judicial Council, or a local
court rule or local uniform written policy to the contrary, the
methods of discovery may be used in any sequence, and the fact that a
party is conducting discovery, whether by deposition or another
method, shall not operate to delay the discovery of any other party.
However, on motion and for good cause shown, the court may establish
the sequence and timing of discovery for the convenience of parties
and witnesses and in the interests of justice.
   (d) In any action alleging the misappropriation of a trade secret
under the Uniform Trade Secrets Act (Title 5 (commencing with Section
3426) of Part 1 of Division 4 of the Civil Code), before commencing
discovery relating to the trade secret, the party alleging the
misappropriation shall identify the trade secret with reasonable
particularity subject to any orders that may be appropriate under
Section 3426.5 of the Civil Code.
   (e) Section 1013 shall be applicable to any method of discovery or
service of a motion for discovery provided for in this article.