Question

CREATE TABLE vendor ( vendor_id int NOT NULL, vendor_name char(50) NOT NULL, contact_name char(50), CONSTRAINT vendors_pk PRIMARY KEY (vendor_id) );

What is the code to add the foreign key for this table? Can you please add the entire code with mine included. Thank you in advance.

Answer 1

// vendor table -parent table

CREATE TABLE vendor ( vendor_id int NOT NULL, vendor_name char(50) NOT NULL, contact_name char(50), CONSTRAINT vendors_pk PRIMARY KEY (vendor_id) );

// dealer table -child table. 
CREATE TABLE dealer
( dealer_number int NOT NULL,
  dealer_name char(50) NOT NULL,
  dealer_id int,
  CONSTRAINT dealer_pk PRIMARY KEY (dealer_number),
  CONSTRAINT fk_vendor
    FOREIGN KEY (vendor_id)
    REFERENCES vendor(vendor_id)
);

// if you want to add foreign key to vendor table only, then

CREATE TABLE vendor ( vendor_id int NOT NULL, vendor_name char(50) NOT NULL, contact_name char(50), CONSTRAINT vendors_pk PRIMARY KEY (vendor_id),

CONSTRAINT fk_parent_table
    FOREIGN KEY (parent_table_primary_key)
    REFERENCES parentTable(parent_table_primary_key) );