Q:

Column with Unique Index and Primary Key gives Unique Constraint Violation

I just created a Table on PL/SQL Devloper. The Table I created has an ID column. For this column, I set up a primary key (PK_ID). The column also has a unique index with name PK_ID.
I tried to insert into this table by writing this:
INSERT INTO ADMIN.MESSAGE_LIST (TEXT, TEXTER, ID)
VALUES ('This is a Test','Tim', 1）;

And I get the error "ORA-00001: unique constraint (ADMIN.PK_ID) violated"
I have no other inserts in the table (it is currently empty) and I figured inserting 1 as the ID would be unique.
I also do not have a sequence and trigger set up to auto-increment the ID column, because I honestly do not know how to edit the table to do that (which is why I just inserted with the ID as 1 as a test).
Why can't I insert with an ID 1 if the table is empty? Wouldn't it still be unique in that case?
(Note: Running the command without including ID and the Value 1 gives me an error saying I cannot insert "NULL" into the ID column)

A:

Please execute a simple statement:
select * from admin.message_list where id = 1;

If it wouldn't return rows, you should check if constraint PK_ID refers to ID column and if so, ask Oracle support to fix a bug. 

