Answers for "difference between primary key and unique key and foreign key and composite key cheat sheet"

unique vs primary key

What is the difference between UNIQUE and PRIMARY KEY constraints? 
There should be only one PRIMARY KEY 
in a table whereas there can be
any number of UNIQUE Keys.
PRIMARY KEY doesn’t allow NULL
values whereas Unique key allows NULL values.

Posted by: Guest on December-23-2020

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Answers for "difference between primary key and unique key and foreign key and composite key cheat sheet"

Code answers related to "difference between primary key and unique key and foreign key and composite key cheat sheet"

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Answers for "difference between primary key and unique key and foreign key and composite key cheat sheet"

Code answers related to "difference between primary key and unique key and foreign key and composite key cheat sheet"

Code answers related to "SQL"

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