Which of the following will be a consequence of defining the column IDCOL2 in TABLE2 as a foreign key referencing the primary key (IDCOL1) of TABLE1?（）

A、DB2 will no longer allow updating the value of IDCOL1 in TABLE1.

B、When inserting a row in TABLE2, the only values that DB2 will allow for IDCOL2 are the existing values of IDCOL1.

C、When inserting a row in TABLE2, DB2 will only allow foreign values for IDCOL2, that is values which do not exist in IDCOL1.

D、When a SELECT statement joins TABLE1 with TABLE2, DB2 will automatically add the condition TABLE1.IDCOL1=TABLE2.IDCOL2 if not specified in the statement.