database logic

brief :

ALTER TABLE A
      ADD CONSTRAINT id
      PRIMARY KEY (id)

ALTER TABLE B
ADD COLUMN a_id VARCHAR

//add fkey  in B as additional cols
ALTER TABLE B ADD COLUMN a_id int

//now create the fkey ref to agent table on address table
alter table B ADD Foreign key(a_id) references A(id);

//To obtain the generated constraint name of a table
SHOW CREATE TABLE B;


ALTER TABLE B DROP FOREIGN KEY b_ibfk_1;


 //to disable fkey checks.

SET foreign_key_checks = 0/1;





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