Question

I have created a tickets table that holds ID’s for everything so they can all be unique. The tickets table is inserted with new data BEFORE insert on other tables. I need to put the ID that was generated in the tickets table into other tables in one fell swoop.

Here’s how it will run;

1. Query to insert data into table1
2. Trigger insert of the ref and an auto incremented ID in tickets
3. ID from tickets inserted back into table1 as well as the data from the first query.
4. More goes on after this but that’s sorted.

Here’s what I have so far.

delimiter |

CREATE TRIGGER status_ref BEFORE INSERT ON status
FOR EACH ROW BEGIN
 INSERT INTO tickets SET ref = S;

 END;
|

delimiter ;

Answer 1

I recommend you rethink your numbering scheme: Right now, you are double-linking: The tickets table refers to the details via ref, and the details table refers to the tickets table via its ID.

This is not a good idea: Think of a later update to one of the tables, that desynchronizes this double link: Either you disallow that, which renders the second number absolutely meaningless, or you allow it, in which case you end up with different results depending on which field you use for a JOIN.

You should chose a numbering scheme with one leading table – I personally would simply drop the requirement to link tickets.ID back into the details table.

Edit

Seems this was a misunderstanding of my part as for the meaning of the ref field – judging by the other comment, I was not alone with this.

If the ref field carries information about the type of reference only, you have an easy option: create an additional field refID on the tickets table, that stores the (auto incrementing) ID field of the details table. You would need something like

ALTER TABLE tickets ADD COLUMN refID INT NOT NULL;

-- the following only if you not already have it
ALTER TABLE status ADD COLUMN ID INT AUTO_INCREMENT PRIMARY KEY;

CREATE TRIGGER status_ref BEFORE INSERT ON status
FOR EACH ROW BEGIN
 INSERT INTO tickets SET ref = S, refID=NEW.ID;
END;

This stores the detail-table ID in the tickets table.