This page summarizes the data modeling profile for UML Class Diagrams, that I apply in Agile Database Techniques, The Object Primer 3rd Edition, and Refactoring Databases. First some important definitions:

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Logical data models (LDMs). LDMs are used to explore either the conceptual design of a database or the detailed data architecture of your enterprise. LDMs depict the logical data entities, typically referred to simply as data entities, the data attributes describing those entities, and the relationships between the entities.
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Physical data models (PDMs). PDMs are used to design the internal schema of a database, depicting the data tables, the data columns of those tables, and the relationships between the tables.
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Conceptual data models. These models are typically used to explore domain concepts with project stakeholders. Conceptual data models are often created as the precursor to LDMs or as alternatives to LDMs.