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Search results: Foreign keys

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Data & databases

Choose a PostgreSQL foreign-key deletion policy without losing the wrong rows

Compare RESTRICT, CASCADE and SET NULL using a small isolated example, then check the actual constraint and dependent rows before changing real data.

PostgreSQL / SQL / Foreign keys / Transactions

Data & databases

Why JOIN Multiplies Rows: Matching Keys, Constraints and Output Grain

Diagnose repeated JOIN rows by counting matching keys, checking constraints and choosing whether the result should contain orders, items or summaries.

SQL / JOIN / PostgreSQL