Take the 2-minute tour ×  I have little problem with programming
trigger for my dtb. I need to control 2 values in one 1 table. I
have table called Concert and it has 2 foreign keys: 1 is the id
of table Place. Second is not important for this I think.
Concert: id_concert, id_place<fk>, id_organizer<fk>, date, name,
sponsor  Place: id_place, name, capacity, adress, town  What I
want to eliminate is, that 2 concerts organized at same day
cannot be on one place. So, I need to somehow control that user
cannot insert the same date and same place for concert if there
already concert with this values exists.  Thank you very much
for your suggestions and sorry for bad english.  share|improve
this question What type of database is this ie MySQL, Oracle,
SQL Server.... –  JStead Jan 15 '12 at 15:51 Oracle database :)
–  JS_Diver Jan 15 '12 at 19:18 add comment  1 Answer  You need
to add a unique constraint on your Concert table that consists
of the (id_place, date) pair. This would instruct the database
engine to not