Most likely an easy answer here, I really hope, but appears just like a difficult question to place into words.

For those who have an overseas Key that basically seems two times inside a table, originating from two Composite Secrets does that FK then need to be defined two times (exist as two separate characteristics)?

Here are a few simple models to visualise things i am asking. Ex. 1 shows the FK of Table1Id like a single attribute. Ex. 2 shows the FK of Table1Id (recognized as Table1Id_FKTable2 &lifier Table1Id_FKTable3) as two different characteristics.

Based on what you would like to complete are these two models valid? enter image description here

Usually, the table1ID_FKTable2 is much better known as a "role" that Table1 plays regarding Table4.

Together with, table1ID_FKTable3 is really a different "role" that Table1 plays regarding Table4.

The thought of role is pervasive. Two employees fit in with exactly the same company, but might have different roles, one as person in the board of company directors, another as an ingredient-time, hourly.

I'm attempting to understand your question, but when the main key of Table2 is really a composite of Table1Id and Table2Id you will want to produce a foreign key from Table4 using both fields. Same factor for Table3.

ALTER TABLE Table4 ADD constraint fk_tab2 foreign key references Table2(Table1Id, Table2Id)
ALTER TABLE Table4 ADD constraint fk_tab3 foreign key references Table3(Table1Id, Table3Id)

Your sketches don't "imagine what you're asking", since your sketches don't seem to contain any composite secrets whatsoever.

But when your real question is (something similar to) "Is one able to single attribute in table4 be declared to become a foreign key BOTH into table2 and table3 ?", then the reply is yes.

It might be unlikely whether it labored the way in which you'd would like it to if you are using ID fields everywhere, but neither the relational model nor the SQL standard prevent it.