SQL code for Access database adding multipe foreign keys to a table

I am trying to code a table in Access that has multipe foreign keys. This is what I have so far:

CREATE TABLE Activities
(
[actID] Counter NOT NULL,
[stoID] Int NOT NULL, 
[TaskOrderID] int NOT NULL,
[actdesc] Varchar(100) NOT NULL,
[acttypeID] Int NOT NULL,
PRIMARY KEY (actID, stoID, TaskOrderID),
FOREIGN KEY (stoID) REFERENCES SubTaskOrders (stoID),
FOREIGN KEY (TaskOrderID) REFERENCES TaskOrders (TaskOrderId),
FOREIGN KEY (acttypeid) REFERENCES ActivityType (acttypeid)
);

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I am getting the error message: “No unique index found for the referenced field of the primary table.”

I know I must be coding this wrong, but I am also not sure what this error message means, or why I am getting it.

I can't wait to hear what I am doing wrong!

Thank you in advance!
MeginAsked:
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Scott McDaniel (Microsoft Access MVP - EE MVE )Connect With a Mentor Infotrakker SoftwareCommented:
Not necessarily.

Also, be aware I'm referring to the "child" tables, and not your Activities table. In other words, the table named TaskOrders must have a Unique constraint, and that constraint must include the field you're referencing as a foreign key.
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Scott McDaniel (Microsoft Access MVP - EE MVE )Infotrakker SoftwareCommented:
That means one or more of your referenced tables (SubTaskOrders, TaskOrder or ActivityType) do not have a Unique Constraint on them, or more specifically on the field that you're referencing from those tables. For example. SubTaskOrders.stoID may not be defined as a "Unique Constraint".
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MeginAuthor Commented:
So, making something a primary key is not enough to satisfy that?
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MeginAuthor Commented:
Also, I am looking for the code I have to alter a table, because I am assuming that is the only way I am going to be able to change a field to for this Unique Constraint. But the examples are for adding keys, deleting columns, etc. What would be proper code be to add this particular thing to the table?
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MeginAuthor Commented:
I just went in and figured out the Alter table syntax to add UNIQUE to all my primary keys. It looks like that worked.

Thank you for the help!
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