Databases Reference
In-Depth Information
Once again, use the Object Type select list and choose Triggers. You see a trigger named
BI_TICKETS
(BI stands
for “before insert”). Clicking the Code tab above the trigger details shows the code for the trigger that is using the
TICKETS_SEQ
sequence to fill the
TICKET_ID
if it's null. You should see code similar to the following:
create or replace trigger "BI_TICKETS"
before insert on "TICKETS"
for each row
begin
if :NEW."TICKET_ID" is null then
select "TICKETS_SEQ".nextval into :NEW."TICKET_ID" from sys.dual;
end if;
end;
Now that you have the
TICKETS
table defined, let's go back and create the
TICKET_DETAILS
table. This time you'll
create a foreign key to the
TICKETS
table, as a
CASCADE DELETE
. This means that if you delete a ticket, the ticket details
will automatically be deleted as well.
10.
Start the Create Table Wizard using the
Create
button.
11.
Enter the table name and column definitions based on the ERD and Figure
4-6
, and
click
Next
.
Figure 4-6.
Defining the
TICKET_DETAILS
table
