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BP Server Developer's Guide
Process instance migration : Filters for migration
 

Filters for migration

While selecting instances for migration, you can define your own filters to ensure the validity of the migrated instance. For example, if an active workstep in the source process instance joins to a newly added AND workstep in the target process instance, and if one of the input to an AND workstep is already completed before or it is a newly added workstep.
BP Server adds a default filter condition that the source instance can be migrated only if all the active workstep instances have human performers. You can also add additional filter conditions on workstep instance attributes and dataslot values in Business Process Portal. The Filter XML file is generated internally and is stored in the database when a filter is created in Business Proccess Portal. An example of the Filter XML markup is shown below:
<InstanceFilter name="PartPurchase_v1_filter1">
    <Application source="PartPurchase_v1">
        <Condition>
             BLWSI.workstep_name in ('ws1','ws3') AND BLWSI.state != 15
         </Condition>
    </Application>
</InstanceFilter>
Note that the filter condition should be SQL92 compliant. A filter condition may include conditions on workstep instance attributes, instance dataslot values, and global dataslot values. The Table 5 describes the aliases for BP Server tables that can be used in this SQL92 complaint query. Note that these prefixes are the same as those defined in QueryService.
Table 5. Aliases for BP Server tables
Table name
Prefix
BP Server_WorkStepInstance
BLWSI
Instance Dataslot table
BLIDS
Global Dataslot table
BLGDS
When the specified conditions do not involve any instance dataslots or global dataslots, BP Server constructs the query without joining to the instance and global dataslot table for performance reasons.
When a filter is attached to a migration run, the SQL92 compliant condition specified in the filter object is appended to the above query. The default condition of BP Server and the user-specified conditions through the filter object together select the qualified instances for migration.