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How can I do the composite key in the database?

I want to creat table that include just two culmon and both are foreign key.. which that two will be primary key.. how can I do that in mysql?

25th Apr 2020, 11:49 AM
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4 Antworten
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Just set both of them as primary key. It automatically become a composite key. So if you have folkowing values column1 | column2 1 | 6 1 | 3 There will be no error
25th Apr 2020, 12:05 PM
Ore
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Thank u a lot
25th Apr 2020, 4:48 PM
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So if I use this query ALTER TABLE Orders ADD FOREIGN KEY (PersonID) REFERENCES Persons(PersonID); For both column it will be correct yes?
25th Apr 2020, 2:00 PM
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👩🏻__🇴🇲 You have to set the ON UPDATE constraint to CASCADE ALTER TABLE Orders ADD FOREIGN KEY (PersonID) REFERENCES Persons(PersonID) ON UPDATE CASCADE
25th Apr 2020, 4:37 PM
Ore
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