Add Unique Constraint to the Inquiry Table

[alexanderkiel]

I had the following exception:

DEBUG [SamplyShareScheduler_Worker-5] de.samply.share.client.job.CollectInquiriesJob - No specific entity requested
[SamplyShareScheduler_Worker-5] ERROR org.quartz.core.JobRunShell - Job DecentralSearchGroup.CollectInquiriesJob threw an unhandled Exception: 
org.jooq.exception.TooManyRowsException: Cursor returned more than one result
        at org.jooq.impl.Tools.fetchOne(Tools.java:1816)
        at org.jooq.impl.AbstractResultQuery.fetchOne(AbstractResultQuery.java:545)
        at org.jooq.impl.AbstractResultQuery.fetchOneInto(AbstractResultQuery.java:568)
        at org.jooq.impl.SelectImpl.fetchOneInto(SelectImpl.java:2899)
        at de.samply.share.client.util.db.InquiryUtil.fetchInquiryBySourceIdAndBrokerId(InquiryUtil.java:89)
        at de.samply.share.client.job.CollectInquiriesJob.addInquiryDetails(CollectInquiriesJob.java:225)
        at de.samply.share.client.job.CollectInquiriesJob.loadAndPersistInquiries(CollectInquiriesJob.java:117)
        at de.samply.share.client.job.CollectInquiriesJob.execute(CollectInquiriesJob.java:77)
        at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573)

The fetchInquiryBySourceIdAndBrokerId method looks like this:

public static Inquiry fetchInquiryBySourceIdAndBrokerId`(int sourceId, int brokerId) {
    DSLContext dslContext = ResourceManager.getDslContext();
    return dslContext
        .selectFrom(Tables.INQUIRY)
        .where(
            Tables.INQUIRY.SOURCE_ID.equal(sourceId)
                .and(Tables.INQUIRY.BROKER_ID.equal(brokerId))
        )
        .fetchOneInto(Inquiry.class);
  }

I had one result regarding this query:

select source_id, broker_id, count(*)
from samply.inquiry group by source_id, broker_id having count(*) > 1;

So we need a unique constraint over the columns source_id and broker_id in order to guaranty uniqueness for the query in fetchInquiryBySourceIdAndBrokerId.