mysql - How do I add a boolean that can only have one true for one column name of the same type? -

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i have table called computer , column office_id, computer_name, server. each office id have 1 computer server. if have multiple computers in office. 1 computer in office server , server required. there can't office no server.

if try implement in computers table, need use trigger in mysql. other databases support things filtered indexes , computed columns making unnecessary, not mysql.

instead, add column offices table:

create table offices (     . . . ,     serverid int not null,     foreign key (serverid) references computers(computerid) );

this guarantee each office has 1 server. might need trigger guarantee officeid in computers table matches officeid in offices table, though.


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