12 lines
358 B
Markdown
12 lines
358 B
Markdown
# Foreign Key
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A Foreign key is a [[Constraint]] that protects links between tables. Foreign key is a attribute or attributes that link to the [[Primary Key]] of a other entity set (table).
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## Example
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|ID (PK)|Name|Age|Sex|Length|
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|-----|-----|-----|-----|-----|
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|1|Nick|21|M|190|
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|ID (PK)||Age|Sex|Length|
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|-----|-----|-----|-----|-----|
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|1|Nick|21|M|190| |