This document introduces a novel one-to-many data linkage method using a one-class clustering tree (occt), which facilitates linking different types of entities. The proposed technique addresses key issues in data linkage, surpassing traditional one-to-one methods by enabling connections between various datasets and improving performance in precision and recall compared to existing approaches. The paper evaluates the method across three domains and outlines its advantages, including data leakage prevention and the ability to detect abnormal database access.