Entity XREF Section

New entity xreference identifiers can be inserted into the RULESDBO.ENTITY_XREFERENCE DB table with Generic Entity interface.
For the newly added identifiers only 'Find 1st Match' mode of Entity Resolution logic can be used.

Insert New Entity XREF Record

<EagleML xmlns="http://www.eagleinvsys.com/2011/EagleML-2-0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" eaglemlVersion="2-0" eaglemlType="EntityTransactionMessage" xsi:schemaLocation="http://www.eagleinvsys.com/2011/EagleML-2-0 eagleml-main-2-0.xsd" xsi:type="EntityTransactionMessage">
	<header>
		<messageId messageIdScheme="http://www.eagleinvsys.com/coding-scheme/message-id-2-0">TEST</messageId>
	</header>
	<entityTransaction>
		<header>
			<objectType>GenericEntity</objectType>
		</header>
		<genericEntity>
			<objectType>GenericEntity</objectType>
			<objectId>GenericEntity</objectId>
			<objectDescription>ENTITY</objectDescription>
			<sourceName>EAGLE PACE</sourceName>
			<updateSource>MCADMIN</updateSource>
			<entityId>ASXR_E01</entityId>
			<entityName>ASXR_E01</entityName>
			<entityType>PORT</entityType>
			<entityXrefs>
				<entityXref>
					<xrefAccountId>ASXR_E01_XREF1</xrefAccountId>
					<xrefAccountIdType>XREF101</xrefAccountIdType>
					<classCode>TF1</classCode>
				</entityXref>
			</entityXrefs>
			<effectiveDate>2018-05-25</effectiveDate>	
			<accountingBasis>USTAX</accountingBasis>
			<accSysOpeningDate>2018-05-25</accSysOpeningDate>			
			<baseCurrency>USD</baseCurrency>			
			<costMethod>I</costMethod>			
			<countryOfTax>US</countryOfTax>
			<entityLongName>ASXR_E01</entityLongName>
			<fiscalEndDate>2018-05-25</fiscalEndDate>			
			<gainLossPydn>N</gainLossPydn>
			<inceptionDate>2018-05-25</inceptionDate>
			<legalName>ASXR_E01</legalName>
			<lotSelectionMethod>FIFO</lotSelectionMethod>
			<conversionDt>2018-05-25</conversionDt>
			<fxSource>EAGLE PACE</fxSource>
			<priceSource>EAGLE PACE</priceSource>
			<varRateSource>EAGLE PACE</varRateSource>
			<espShortPriceSource>EAGLE PACE</espShortPriceSource>
			<entityPartitionAssignment>1</entityPartitionAssignment>
			<cashSuspenseProc>N</cashSuspenseProc>
			<acctBasis>
				<acctBasis>USTAX</acctBasis>
				<costMethodCash>I</costMethodCash>
				<sinkFundGainLossFlag>Y</sinkFundGainLossFlag>				
				<primaryAmortizationAccreationRule>DEFAULTNONE</primaryAmortizationAccreationRule>				
				<contractualCashSettlementRule>DEFAULTNONE</contractualCashSettlementRule>				
				<mtmRateSource>EAGLE PACE</mtmRateSource>
				<xrateValSource>EAGLE PACE</xrateValSource>
				<valuePacePosAtCostFlag>N</valuePacePosAtCostFlag>
			</acctBasis>
		</genericEntity>
	</entityTransaction>
</EagleML>

You can use Generic Entity interface without Accounting Validation Flag. Entity batting order and entity resolution option are not required and can be omitted in the incoming message.

...
<entityId>ASXR_E01</entityId>
<entityName>ASXR_E01</entityName>
<entityType>PORT</entityType>
<entityXrefs>
   <entityXref>
      <xrefAccountId>ASXR_E01_XREF1</xrefAccountId>
      <xrefAccountIdType>XREF101</xrefAccountIdType>
      <classCode>TF1</classCode>
   </entityXref>
</entityXrefs>...

1 record will be added to ENTITY_XREFERENCE table with Xref Id = ASXR_E01_XREF1 and Type = XREF101

Update the Entity XREF Record

To update Entity Xreference with type = XREF101 use the following construction:

...
<entityId>ASXR_E01</entityId>
<entityName>ASXR_E01</entityName>
<entityType>PORT</entityType>
<entityXrefs>
   <entityXref>
      <xrefAccountId>ASXR_E01_XREF2</xrefAccountId>
      <xrefAccountIdType>XREF101</xrefAccountIdType>
      <classCode>TF1</classCode>
   </entityXref>
</entityXrefs> 
...

<EagleML xmlns="http://www.eagleinvsys.com/2011/EagleML-2-0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" eaglemlVersion="2-0" eaglemlType="EntityTransactionMessage" xsi:schemaLocation="http://www.eagleinvsys.com/2011/EagleML-2-0 eagleml-main-2-0.xsd" xsi:type="EntityTransactionMessage">
	<header>
		<messageId messageIdScheme="http://www.eagleinvsys.com/coding-scheme/message-id-2-0">TEST</messageId>
	</header>
	<entityTransaction>
		<header>
			<objectType>GenericEntity</objectType>
		</header>
		<genericEntity>
			<objectType>GenericEntity</objectType>
			<objectId>GenericEntity</objectId>
			<objectDescription>ENTITY</objectDescription>
			<sourceName>EAGLE PACE</sourceName>
			<updateSource>MCADMIN</updateSource>
			<entityId>ASXR_E01</entityId>
			<entityName>ASXR_E01</entityName>
			<entityType>PORT</entityType>
			<entityXrefs>
				<entityXref>
					<xrefAccountId>ASXR_E01_XREF2</xrefAccountId>
					<xrefAccountIdType>XREF101</xrefAccountIdType>
					<classCode>TF1</classCode>
				</entityXref>
			</entityXrefs>
			<effectiveDate>2018-05-25</effectiveDate>	
			<accountingBasis>USTAX</accountingBasis>
			<accSysOpeningDate>2018-05-25</accSysOpeningDate>			
			<baseCurrency>USD</baseCurrency>			
			<costMethod>I</costMethod>			
			<countryOfTax>US</countryOfTax>
			<entityLongName>ASXR_E01</entityLongName>
			<fiscalEndDate>2018-05-25</fiscalEndDate>			
			<gainLossPydn>N</gainLossPydn>
			<inceptionDate>2018-05-25</inceptionDate>
			<legalName>ASXR_E01</legalName>
			<lotSelectionMethod>FIFO</lotSelectionMethod>
			<conversionDt>2018-05-25</conversionDt>
			<fxSource>EAGLE PACE</fxSource>
			<priceSource>EAGLE PACE</priceSource>
			<varRateSource>EAGLE PACE</varRateSource>
			<espShortPriceSource>EAGLE PACE</espShortPriceSource>
			<entityPartitionAssignment>1</entityPartitionAssignment>
			<cashSuspenseProc>N</cashSuspenseProc>
			<acctBasis>
				<acctBasis>USTAX</acctBasis>
				<costMethodCash>I</costMethodCash>
				<sinkFundGainLossFlag>Y</sinkFundGainLossFlag>				
				<primaryAmortizationAccreationRule>DEFAULTNONE</primaryAmortizationAccreationRule>				
				<contractualCashSettlementRule>DEFAULTNONE</contractualCashSettlementRule>				
				<mtmRateSource>EAGLE PACE</mtmRateSource>
				<xrateValSource>EAGLE PACE</xrateValSource>
				<valuePacePosAtCostFlag>N</valuePacePosAtCostFlag>
			</acctBasis>
		</genericEntity>
	</entityTransaction>
</EagleML>

Xref Account Id will be updated from ASXR_E01_XREF1 to ASXR_E01_XREF2.

It is also possible to update Xrefs via Acсounting Entity rule (with Accounting Validation Flag = Y), the logic is the same.