Insert missing rows in table b and update table a

Question

I have 2 tables: user_account and email_validation . user_account has user_id , email and email_validation_id . email_validation has email_validation_id , user_account_id , and email .

In normal and correct way, for each user in user_account (for example [user_id="123", email="user@domain.com", email_validation_id="456"] ) there is a row in email_validation (for example [email_validation_id="456", user_account_id="123", email="user@domain.com"] ).

But, some things got wrong and now I have users with no email validation. So, I would like to add rows manually: for each user from user_account which don't have a row in email_validation (ie no row with it's user_id ) insert [email_validation_id=<The current max of (email_validation.email_validation_id) + 1>, user_account_id=<user_account.user_id>, email=<user_account.email>] and update the user_account.email_validation_id to <email_validation.email_validation_id> .

I have no idea how to approach this :\\

Thank you for your time!

Answer 1

If I had understood everything correctly this could help.

Missing email validation

To create/insert missing email validation you can do.

INSERT INTO email_validation(user_account_id, email)
SELECT user_id, email
FROM user_account WHERE email_validation_id is null;

Auto increase the id

To auto increase the id you can do.

Table definition:

CREATE TABLE tablename
(
  id NUMBER(10)
);

ALTER TABLE tablename ADD (CONSTRAINT tbn_pk PRIMARY KEY (id));
CREATE SEQUENCE tbn_seq START WITH 1;

Or you can use Identity Columns is available from Oracle 12c+.

CREATE TABLE tablename
(
   id NUMBER GENERATED ALWAYS AS IDENTITY
);

Trigger definition:

CREATE SEQUENCE tbn_seq START WITH 1;

CREATE OR REPLACE TRIGGER tbn_id_insert BEFORE INSERT ON departments 
FOR EACH ROW
BEGIN
    SELECT tbn_seq.NEXTVAL
    INTO :new.id
    FROM dual;
END;
/

Update the user_account

To update the user_account.email_validation_id you can do.

DECLARE
    v_email_validation_id user_account.email_validation_id%TYPE;
BEGIN
    FOR user_account_rec IN (SELECT * FROM user_account WHERE email_validation_id is NULL)
    LOOP
        SELECT email_validation_id
        INTO v_email_validation_id
        FROM email_validation
        WHERE user_account_id = user_account_rec.user_id;

        UPDATE user_account
        SET email_validation_id = v_email_validation_id
        where user_id = user_account_rec.user_id;
    END LOOP;
END;
/

I hope I was able to help you.