1. A method, implemented in at least one processor, for constructing a database to deduce a disease, the method comprising: the at least one processor: analyzing U-Health information, which includes a disease, a symptom, and a treatment, and constructing a plurality of U-Health ontologies required for service provision; setting a meta-model defining cause-and-effect relationships between the constructed U-Health ontologies; and selecting a subset of the constructed U-Health ontologies comprising at least two specific U-Health ontologies from among the plurality of U-Health ontologies, setting the selected U-Health ontologies as nodes, generating a Bayesian network by applying the meta-model to the set nodes to thereby construct a customized database for inferring a disease of a user; whereby upon receiving personal information of the user, a disease of a user is inferred using a probabilistic analysis of said Bayesian network.