Do I need to create a view for this?

Question

Hi Ihave got 2 tables emp and project
In emp tabe:
emp_no
family name
given name
In porgect table:
emp_no
status(assigned,unassigned)
start_date
end_date
emp_no Family_name given_name
1 Smith John
In project table same employee can have many assigement eg
emp_no status start_date end_date
1 assigned 01-may-08 01-july-08
1 assigned 01-sep-08 01-july-09
1 unassigned 01-july-09 01-oct-09
In the form:
there are 2 querable fields "project ends between field1(date) and field2(date)" which is used to
retrive records which have end date between field1 and field2.
The following fields are needed to get from database:
emp.family_name emp.given_name project.start_date project.end_date No.of time assigned
Requirements:
1. project.start_date and project.end_date must be the latest project_end_date for the same emp
so in the above sample date
2. No. of time assigned is a count of total of number records which have status='assign'
So for the given sample data the record expected after query would be(field1=01-jun-08 field2=02-july-09)
emp.family_name emp.given_name project.start_date project.end_date No.of time assigned
Smith John 01-sep-08 01-july-09 2
What is the best approach to get:
1 The lastest project(latest end_date) for the emp
2. get No.of time assigned.
Do I need to create a view for this? If yes, any sample sql code this this?
Thanks for your help

Answer 1

Hi W1zard,
Thanks for your reply. Could you clarify the following points for me:
1.) you could create a master block basing on your emp table and a detail block basing on your project table with the relation over emp_no. set the default_where clause of your detail block programmatically using
set_block_property('project', default_where, 'status = ''assigned'' and <your_date_criteria>');
Q1: where I pit this code? in pre-query trigger in detail block?
2.) Of course you could create a view to join both of your tables if you don't want to use master detail blocks; Also do the join over emp_no
create or replace force view v_emp as
select emp.family_name, emp.given_name, project.start_date, project.end_date
from emp, project
where emp.emp_no = project.emp_no
Q2 As I mentioned before, there are multipal entries for the same emp in project table and we only need the maching record from project table which has latest end_date. So I think I need something like
max(project.end_date) somewhere in create view to make sure only one record for one employee.
Also is there possible to include the no. of assigned field(select count(*) from project where status='assigned' and emp=emp_no) into the view as well?
Q3 All the fields mentioned above are diaplay-only. So Can I create a control block which has all the fields from emp and project. Then populate them with my sql. The question is
where I put this customerised sql so when user click excute query. My sql will run and display one the form?
REally appreciated your help!
Michael