Real Time Information Director User Documentation

RTID Metadata Language
Hewlett-Packard Company 69 529618-002
Using Dependent Links to Select Child Records
Although the <KEYS> section of a query is of crucial importance for selecting records,
related (child) records must be selected by other means. For example, consider the
following query document, called ChinnQueryMichaelEventsHistory.xml, in the folder
C:\rtid\chin\inputs:
<PATIENTEVENTSHISTORY_R>
<HEADER>
. . .
</HEADER>
<KEYS>
<EXTERNALIDENTIFIER>PAT00002</EXTERNALIDENTIFIER>
<IDENTIFIERTYPECODE>CRN</IDENTIFIERTYPECODE>
</KEYS>
</PATIENTEVENTSHISTORY_R>
The keys make it possible to retrieve information for a person using the person’s external
identifier as a key. But only the PERSON table contains the EXTERNALIDENTIFIER value.
The nested ENCOUNTER table is keyed by the UNIQUEIDENTIFIER column, which is
not provided in the input keys. To make it possible to retrieve medical-encounter
information, the document definition uses an object called DependentLinks, as shown in
the following excerpt from the file PatientEventsHistory.java. This document definition
refers to several enriched records defined in the file EHR.java.
private static DocumentRecord documentRecord =
new DocumentRecord(EHR.personRecord, new RelatedRecords[] {
new RelatedRecords(EHR.encounterRecord, new
DependentLinks("UNIQUEIDENTIFIER"), new RelatedRecords[] {
new RelatedRecords(EHR.externalChartEntryRecord, new
RelatedRecords[] {
…
}
}
The DependentLinks metadata object specifies that only the ENCOUNTER records that
have the same UNIQUEIDENTIFIER value as the PERSON record are selected. In other
words, the top-level PERSON record is selected based on the KEYS values from the
input. That record also contains a value for UNIQUEIDENTIFIER, which correlates
with the EXTERNALIDENTIFIER value in the input. Thus child records of PERSON should
be selected only if the value of UNIQUEIDENTIFIER in the child record matches the
value of UNIQUEIDENTIFIER in the parent record.
Incidentally, if you look at the file EHR.java, you’ll see that the definition of
externalChartEntryRecord uses the OrderBy enrichment to control the order of output
records. In this case, Encounter records are returned in descending order by the date.