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When does duration preserved when dates are changed manually / programatically RRS feed

  • Question

  • Hello,

    In some cases, when I change manually the start date, duration is preserved and finish date is changed accordingly. On other cases, finish is preserved and duration changes.

    I tried to work out the logic. This is what I came out with:

    1. If finish date was never changed manually, duration is preserved
    2. If the new start date is later than the current finish date, duration is preserved
    3. Otherwise, finish date is preserved

    My questions:

    1. Is this exact?
    2. Is this documented?
    3. Can I change this logic?
    4. In rule #1, where does project stores the information if I changed finish in the past?
    Friday, March 1, 2019 10:12 AM

Answers

  • Hi Barak,

    Assuming autoscheduled tasks with zero % complete and no resources then....

    1. Your testing is correct;

    2. as to whether it is documented, I don't believe so.

    3. No

    4. I've never seen it explicitly defined.


    Ben Howard [MVP] | web | blog | book | downloads | P2O

    Friday, March 1, 2019 10:56 AM
    Moderator
  • If you type in a start date, you will impose a Start No Earlier Than date constraint.

    If you type in a finish date, ie a date in a date into the finish field, you will impose a Finish No Earlier Than (FNET) date constraint.

    MSP does whatever it has to do to honour the constraint.

    In task information, advanced you can see the 8 different date constraint types.

    You want to avoid typing in dates at all, and instead use correct predecessor/successor links, have all tasks ASAP, and allow the dates to be calculated.

    1 it doesn't really matter, does it?
    2 no
    3 why?
    4 no one knows

    Friday, March 1, 2019 2:12 PM

All replies

  • Hi Barak,

    Assuming autoscheduled tasks with zero % complete and no resources then....

    1. Your testing is correct;

    2. as to whether it is documented, I don't believe so.

    3. No

    4. I've never seen it explicitly defined.


    Ben Howard [MVP] | web | blog | book | downloads | P2O

    Friday, March 1, 2019 10:56 AM
    Moderator
  • If you type in a start date, you will impose a Start No Earlier Than date constraint.

    If you type in a finish date, ie a date in a date into the finish field, you will impose a Finish No Earlier Than (FNET) date constraint.

    MSP does whatever it has to do to honour the constraint.

    In task information, advanced you can see the 8 different date constraint types.

    You want to avoid typing in dates at all, and instead use correct predecessor/successor links, have all tasks ASAP, and allow the dates to be calculated.

    1 it doesn't really matter, does it?
    2 no
    3 why?
    4 no one knows

    Friday, March 1, 2019 2:12 PM
  • Thank you Ben and Trevor for your replies.

    The reason I look into this is that I want to bring some dates to MS Project from an external system while letting project managers control dates of other tasks.

    I look into a way to set the dates programtically and get the expected results. 

    Your answers were very helpful.

    Many Thanks,

    Barak

    Friday, March 1, 2019 4:08 PM