MySQL Learning Note (8) the relationship between entities

Linkages between entities: the link between records and records of a table

1-to-many, many-to-1

Scenario: In a multi-terminal relationship, add a field to hold the entity identity of the current entity's contact end.

Many-to-many

Scenario: Add a Relationship table to ensure the clarity of the relationship.

1 to 1

Solution: Put the common information in the main table, the less commonly used information in the extension table, reduce the main table size, improve the main Table query speed and legibility.

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MySQL Learning Note (8) the relationship between entities