oracle trigger delete after insert

Question

I have a table "person"

id groupId occupation state
1  5       DIRECTOR   RETIREMENT
2  5       TEACHER    VACATION
3  4       DIRECTOR   ACTIVE

I need a trigger that delete new inserted row if it has the same grupiId, the same occupation and state ACTIVE. For example: If I insert a row with groupId 4, function Teacher, state wherever - it's OK. If I insert a row with groupId 4, function Director, state HOLIDAY- it's OK. But If I insert a row with groupId 4, function Director, state ACTIVE it should be deleted after insertion

Answer 1

Don't use a trigger for this. Just use a unique constraint or index:

alter table person add constraint unq_person_groupid_function
    unique (groupid, function);

As a note: function is a poor choice for a column name, because it is a SQL keyword.