Question

I have a db table(Hibernate conf all done),

  ResourceRequest( resource, startTime, endTime, status )

between the startTime and endTime the resource is occupied.

Problem Statement:
For a input of inStartTime and inEndTime, I have to find the next available slot if it is already occupied in the given slot.
Have to write a hibernate query for this.

One quick solution that I could think of is:
Querying the resourcerequests for the given resource into a collection and then manipulating it to get the next available slot.

But I want have that as my last resort. Any help is appreciated.

thanks.

Answer 1

in sql

SELECT * FROM slots s1 WHERE
    s1.endTime > :inStartTime AND
    not exists (SELECT 1 FROM slots s2 WHERE s2.startTime > s1.endTime AND s2.startTime < DateAdd(s1.endTime, :inEndMinusInStart))
ORDER BY
    s1.startTime


// and criteria to tweak

DetachedCriteria subquery = DetachedCriteria.for(Slot.class)
    .add(<filter on resource>)
    .add(Restrictions.propertyGt("startTime", "s1.endTime"));
    .add(Restrictions.propertylt("startTime", Projections.sqlFunction("dateadd", Projections.property("s1.endTime"), inStartTime - inEndTime, Hibernate.dateTime));

session.createCriteria(Slot.class, "s1")
    .add(<filter on resource>)
    .add(Restrictions.gt(endTime, inStartTime))
    .add(Subqueries.notExists(subquery))

hope it helps