Limitation on number of predecessors?

[Digman]

Can anyone tell me if there is a limitation on the number of tasks that can
be assigned as predecessors to a single task (single task with multiple
predecessors)?

I am trying to import from MS-Access. I am finding that the predecessors
are being truncated (looks like 255 characters limit). I tried cutting and
pasting the predecessors in manually, but still seems to be truncating them.

I am trying to paste in 150 tasks as predecessors (4 characters per task
plus the comma). I am using MS-Project 2007.
The reason I have so many preds. is because I believe I should avoid using
Summary tasks as predecessors (this would reduce the amount considerably).

 

[JulieS]

Hello Digman,

Yes, the field is limited to 255 characters. You are correct in your
assessment that using summary tasks in predecessor/successor
relationships is not a "best practice." However, as an alternative,
consider placing milestones in your project to mark the end of a summary
task phase. You can link the appropriate tasks within the summary group
to the milestone and then set the milestone task as a single predecessor
to other tasks.

I hope this helps. Let us know how you get along.

Julie
Project MVP

Visit http://project.mvps.org/ for the FAQs and additional
information about Microsoft Project

 

[Jim Aksel]

The Project Spec says there is no limit to the number of predecessors or
successors to a task.

There is a 255 character display limitation in the predecessor/successor
columns.
To include "unlimited" predecessors, you will need to add them either
programatically or on the predecessors tab of the Task Information Dialog box.

Predecessors and successors are part of the TaskDependencies collection of a
task:
Dim t as task
t.TaskDependencies (etc)
--
If this post was helpful, please consider rating it.

Jim Aksel, MVP

Check out my blog for more information:
http://www.msprojectblog.com

 

[HansH]

Theoretically, there is no limit...
In the real world, you are stuck with the 255 character limit.
Especially if you are using Project Server.
I have seen file corruption because the database also is limited to 255
characters for storing predecessors.
This was in version 2003... I'm not sure if it still applies to Project
Server 2007.

But my advice is to re-organize your plan using the tips from JulieS.
Using too many predecessors impacts the readability and manageability of
your plan.

Kind regards,
Hans

Projectopolis <http://msepm.hsquared.be>

 

[Digman]

Thanks all - Very helpful!


--

Dave

Theoretically, there is no limit...
In the real world, you are stuck with the 255 character limit.
Especially if you are using Project Server.
I have seen file corruption because the database also is limited to 255
characters for storing predecessors.
This was in version 2003... I'm not sure if it still applies to Project
Server 2007.

But my advice is to re-organize your plan using the tips from JulieS.
Using too many predecessors impacts the readability and manageability of
your plan.

Kind regards,
Hans

Projectopolis <http://msepm.hsquared.be>

 

[Jim Aksel]

No sir, I routinely exceed 255 characters.
I enter the predecessor information on the Task Information Dialog box.
Only the first 255 characters are *displayed* in the predecessor *column*.

If you wish to try it out, the easiest way to do it is to create a schedule
with a couple of tasks and then link a task to file on an external network
file with a long path name and you will run past 255 characters quickly.
--
If this post was helpful, please consider rating it.

Jim Aksel, MVP

Check out my blog for more information:
http://www.msprojectblog.com

 

[HansH]

What version are you using?

I believe you when you say you are using more than 255 characters all
the time... lucky you... but I also know that this can cause problems...

I have had problems at a customer where using more than 255 characters
for predecessors or successors caused circular references into the project.
But then again this was version 2003, haven't tried it yet in 2007.

Projectopolis <http://msepm.hsquared.be>

 

[Rob Schneider]

I've tried to always avoid lots of predecessor links so I don't have
first hand experience with testing the upper bounds or the creation of
circular links. But just thinking how I would imagine they would have
programmed these arrays and pointers behind the scenes in the
application, it seems to me there is a higher probability of having
circular references being introduced into the project model due to the
complexity of a large number of predecessors causing such links to be
not noticed and hard to figure out. Especially if summary tasks are
involved. Just my to bits. I have a long airplane trip coming up. I
might do some playing with on my laptop on that trip just to see.
Intriguing issue.


--rms

www.rmschneider.com

 

[Jim Aksel]

I've done this in both 2003 and 2007.
As Rob implied in his post, too many predecessors may have you
overconstrained and that may lead to problems including circular references.

You may want to look for predecessors on summary tasks as a place to start.

Please post back if you need additional assistance, plenty of folks here to
help you (as you can see).
--
If this post was helpful, please consider rating it.

Jim Aksel, MVP

Check out my blog for more information:
http://www.msprojectblog.com