<PAGE>
 
                                                                 EXHIBIT 10.2(b)
                                                                                
                  SECOND AMENDMENT TO THE AMENDED AND RESTATED
            DATASTREAM SYSTEMS, INC. STOCK OPTION PLAN FOR DIRECTORS

     THIS SECOND AMENDMENT TO THE AMENDED AND RESTATED DATASTREAM SYSTEM, INC.
STOCK OPTION PLAN FOR DIRECTORS (the "Second Amendment") is made effective as of
the 12th day of March, 1999, by Datastream Systems, Inc., a Delaware corporation
(the "Company").

                              W I T N E S S E T H
                              - - - - - - - - - -
                                        
     WHEREAS, the Company has adopted the Amended and Restated Datastream
Systems, Inc. Stock Option Plan for Directors (as Amended and Restated through
April 12, 1996) (the "Plan"); and

     WHEREAS, Section 11 of the Plan authorizes the Board of Directors of the
Company to make certain amendments to the Plan without stockholder approval; and

     WHEREAS, the Board of Directors now desires to amend the Plan to redefine
the class of transferees to whom non-qualified stock options may be transferred
under the Plan.

     NOW, THEREFORE, the Board of Directors of the Company hereby amends the
Plan as follows:

                                       I.

     Section 10 of the Plan is hereby amended by deleting Paragraph (c) in its
entirety and replacing it with the following new Paragraphs (c) and (d):

          "(c)  Notwithstanding (a) and (b) of this Section 10, a Director may
          assign all or any portion of a non-qualified stock option granted to
          him to (i) the Director's child, stepchild, grandchild, parent,
          stepparent, grandparent, spouse, sibling, mother-in-law, father-in-
          law, son-in-law, daughter-in-law, brother-in-law, sister-in-law, niece
          or nephew, including adoptive relationships, a former spouse of the
          Director or any person sharing the Director's household that is not a
          tenant or employee of the Director; (ii) any entity in which the
          persons included in (i) (or the Director) own more than 50 percent of
          the voting interests; (iii) trusts in which any of the persons
          included in (i) have more than a fifty percent beneficial interest;
          and (iv) foundations in which the persons in (i) (or the Director)
          control the management of assets, as may be permitted under Rule 16b-3
          of the Exchange Act of 1934, as in effect from time to time.  In that
          event, the assignee will be entitled to all of 

                                       1
<PAGE>
 
          the rights of the Director with respect to the assigned portion of
          such non-qualified option, and such non-qualified option will continue
          to be subject to all of the terms and conditions that governed the 
          non-qualified option during the period that it was held by the
          Director; provided, however, that such assignee may not further assign
          the non-qualified option except by will or by the laws of descent and
          distribution. Any such assignment will be permitted only if made by
          gift, pursuant to a domestic relations order, or in exchange for an
          interest in an entity of which more than 50 percent of the voting
          interests are held by the persons included in (i). Additionally, in
          order for an assignment by a Director to be effective, (i) at least 30
          days prior to the date of assignment, the Director must notify the
          Company in writing of the date of the assignment, the non-qualified
          option or portion thereof to be assigned and the name, address,
          telephone number and social security or employer identification number
          of the assignee, (ii) at the time of assignment, the Director must
          execute an appropriate written agreement that the Company provides to
          evidence the assignment and to agree to remit any applicable
          withholding the Company may require and (iii) at the time of
          assignment, the assignee pursuant to a written agreement that the
          Company provides must agree to be bound by the same terms and
          conditions that governed the non-qualified option during the period it
          was held by the Director.

          (d)  A Director, his transferee upon his death and his permitted
          assignee may not transfer any of the Common Stock acquired pursuant to
          the exercise of an Option until six months from the date of grant of
          the Option."

                                      II.

     Except as specifically amended hereby, the Plan shall continue to remain in
full force and effect as before this Second Amendment, and the Second Amendment
shall be effective with respect to any options granted under the Plan, including
those granted before the effective date of this Second Amendment,
notwithstanding any provisions in the applicable non-qualified stock option
agreement to the contrary.

     IN WITNESS WHEREOF, the Board of Directors of the Company has caused this
Second Amendment to be executed in the form and as of the date set forth above.

                                            DATASTREAM SYSTEMS, INC.

                                            By:  /s/ Larry G. Blackwell
                                                -----------------------
                                            Title:  Chairman, President and
                                                    Chief Executive Officer

                                      -2-