I have to create 2 tables. the first one
CREATE TABLE orders ( order_id number(10) NOT NULL, order_name varchar2(50) NOT NULL, payment_id number(10) NOT NULL, CONSTRAINT order_id PRIMARY KEY (order_id), );
and when creating the second one I got this error ORA-02270: no matching unique or primary key for this column-list
CREATE TABLE payment ( payments_id number(10) NOT NULL, payment_name varchar(50) NOT NULL, CONSTRAINT payments_id PRIMARY KEY (payments_id), FOREIGN KEY (payments_id) REFERENCES orders(payment_id) );
not sure what I’m doing wrong
You need to reference a
PRIMARY KEY column. The
payment_id column does not have one of those constraints on it.
From the Oracle constraint documentation:
Foreign Key Constraints
A foreign key constraint (also called a referential integrity constraint) designates a column as the foreign key and establishes a relationship between that foreign key and a specified primary or unique key, called the referenced key.
Instead, you can add an
order_id column to your table:
CREATE TABLE orders( order_id NUMBER(10) NOT NULL, order_name VARCHAR2(50) NOT NULL, CONSTRAINT orders__order_id__pk PRIMARY KEY (order_id) ); CREATE TABLE payment( payments_id NUMBER(10) NOT NULL, payment_name VARCHAR2(50) NOT NULL, order_id NOT NULL, CONSTRAINT payment__payments_id__pk PRIMARY KEY (payments_id), CONSTRAINT payment__order_id__fk FOREIGN KEY (order_id) REFERENCES orders (order_id) );