oracle - No matching unique or primary key for this column-list: SQL -

oracle - No matching unique or primary key for this column-list: SQL -

i working sql , running error ora-02270.

sql> drop table employee; table dropped. sql> create table employee( age varchar(2), gender char(1), employee_no char(6), references worksite(employee_no), primary key(age, gender) ); table created. sql> create table employee_type( age varchar(2) references employee(age), gender char(1) references employee(gender), employee_type varchar(12), primary key (age, gender, employee_type) ); error @ line 3: ora-02270: no matching unique or primary key column-list.

i have read other posts still dont understand error? thought might because have composite key reference columns of composite key.

means says... in obscure way :-)

in this page mysql doc says:

you advised utilize foreign keys reference keys both unique (or primary) , not null.

in other words when write age varchar(2) references employee(age) necessary employee(age) has been defined unique or primary key.

will same employee(gender).

sql oracle