How Database Relationships and SQL Joins Power Everyday Apps

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Database relationships are a foundational concept in backend development, defining how data in one table connects to data in another. Rather than duplicating information, relational databases use primary and foreign keys to link separate tables efficiently. There are three core relationship types: One-to-One, One-to-Many, and Many-to-Many, each suited to different real-world scenarios. A Many-to-Many relationship, such as students enrolling in multiple courses, requires a junction table to bridge the two entities. SQL Joins then allow developers to query and retrieve connected data across these linked tables in a single operation.

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