Dates & Status
External Early Start / Late Finish Stand in for a Missing Project
External Early Start / Late Finish stand in for a lost interproject link
What a planner means
An interproject relationship points at an activity in another P6 project. If both projects are in the same XER, TASKPRED.pred_proj_id / proj_id keep the link. See TASKPRED (Activity Relationships).
If you import one project and the other project is not in the database, that relationship is lost. Oracle then writes two dates on the remaining activity so the scheduler can still honor the missing side:
- External Early Start — early-start stand-in for the lost relationship
- External Late Finish — late-finish stand-in for the lost relationship
They are not Actual Start/Finish, not constraints, not Expected Finish, and not Anticipated Start/Finish (those are WBS/EPS/project planning dates).
Oracle Dates columns (how the stand-in is computed from the lost relationship):
| Lost type | External Early Start | External Late Finish |
|---|---|---|
| FS | relationship early finish | relationship early finish |
| SS | relationship early finish | Relationship Late Start + remaining duration of the predecessor |
| FF | Relationship Early Finish − remaining duration of the successor | relationship early finish |
| SF | Relationship Early Finish − remaining duration of the successor | Relationship Late Start + remaining duration of the predecessor |
A later Oracle work-planning page shortens this to “earliest finish of lost external relationships” / “latest start of lost external relationships.” Prefer the Dates-columns formulas above.
Scheduling so they survive
Oracle: if you re-export a project that still has external dates, schedule it with Ignore relationships to and from other projects marked, or the module will not preserve those external activity dates. That option is SCHEDOPTIONS.sched_outer_depend_type on the XER map (label is the column name). Stored Y/N or enum tokens are unverified.
When the other project is open in the same database, use the real TASKPRED, not these two fields.
XER
| Column | Oracle label |
|---|---|
TASK.external_early_start_date | External Early Start |
TASK.external_late_end_date | External Late Finish |
TASKPRED.pred_proj_id | Predecessor Project |
TASKPRED.proj_id | Successor Project |
SCHEDOPTIONS.sched_outer_depend_type | sched_outer_depend_type |
Empty on most single-project files. Do not invent a ghost TASK row from these dates.
Microsoft Project
Cross-project links become ghost tasks (gray name/bar) plus Links Between Projects. The other file’s task is a placeholder row (project.mpp\ID). That is a different storage model than two dates on the internal activity. Do not map External Early Start to a ghost task and call them the same object.
Don't
- Treat External Early Start / Late Finish as Actuals, as a constraint, or as the activity bar.
- Invent a missing-project activity from these two dates.
- Use them when
pred_proj_idalready points at a project in the same file. - Map them to MSP ghost tasks or to Expected Finish / Must Finish By.