How to validate two instances of the same entity?

How to validate two instances of the same entity?

References

Reference NO 1

http://stackoverflow.com/questions/15200822/how-to-validate-two-instances-of-the-same-entity

Reference NO 2

http://stackoverflow.com/questions/1092534/what-is-the-best-way-to-compare-two-entity-framework-entities

Reference NO 3

http://docs.oracle.com/html/E38269_01/Content/Rules%20using%20entity%20instances/Reason_across_multiple_entities.htm

Reference NO 4

http://docs.oracle.com/html/E24270_01/Content/Data%20model/Use_an_entity%20_or_relationship_in_a_rule.htm

Reference NO 5

http://openjpa.apache.org/builds/1.2.3/apache-openjpa/docs/jpa_overview_pc_identity.html

Reference NO 6

http://msdn.microsoft.com/en-us/library/system.data.entity.infrastructure.dbentityentry(v=vs.103).aspx

Reference NO 7

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Reference NO 8

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