Read a Schema as Business Facts

The fastest way to understand a database is to translate storage into claims. Table A table groups facts of the same kind. If the table name is plural but the row grain is unclear, ask "What does one row assert?" before asking how to query it. Key A key is the database answer to identity. It tells the system which facts are the same fact and which are separate facts. Relationship A foreign key is a business rule made executable: this row can exist only if the referenced row exists. Query A query combines facts. Bad joins usually come from…

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