Workflow Patterns - Oracle SOA Suite 11g R1 Developer's Guide - page 537

<displayColumn> NumberAttribute2 </displayColumn>
<displayColumn> DateAttribute1 </displayColumn>
<displayColumn> TextAttribute3 </displayColumn>
<displayColumn> TextAttribute4 </displayColumn>
</displayColumnList>
Specifying the query predicate
The next step is to specify the query predicate so that it only returns those tasks
that we are interested in. We will first look at the query we need to construct to
return all sold items for a particular seller.
The next screenshot shows the structure of the query predicate . The
assignmentFilter allows us to specify a filter based on who the task is currently
assigned to. Valid values are Admin , All , Creator , My , Group , My+Group , Reportees ,
Owner , Previous , or Reviewer .
For our purposes, we need to list all tasks related to items sold by the specified
seller, so we will need to include those items which have tasks currently assigned
to the buyer.
You may recall that when we defined our workflow, we assigned the initiator (or
creator) of the task to be the seller, so we can use Creator as the assignmentFilter .
So far, our query will return all tasks created by the specified user, which could
potentially include tasks created in other workflows, so we need to add an additional
filter to further restrict our query.
One approach would be to use the keywords filter, which is an optional search string
and if specified, will only return tasks where the string is contained in the task title,
task identification key, or one of the task text flex fields. However, this probably
won't result in the most efficient query. A better alternative is to implement a filter
against the task definition name.