sql - Many to many relationship with additional foreign key that has constraint -


i have database design

installations _______________ id  groups (relation 1:n installations) _______________________________________ id installation_id   services (relation 1:n installations) ________ id installation_id  buttons (relation 1:n services) ___________________________________ id service_id  buttons_enabled _______________ group_id button_id service_id

actually have simplified because in fact there m:m relationship between services , installations.

what constraint buttons_enabled have button services related installations of groups.

so example

installation
inst1
inst2

groups
g1 inst1
g2 inst11

services
s1 inst1
s2 inst1
s3 inst2

buttons
b1 s1
b2 s1
b3 s2
b4 s3

buttons_enabled
g1 b1
g1 b4

last row physically correct not logical beacuse relate 1 group of installation 1 services of installations (b4 related service3 related inst2. g1 related inst1).

how can avoid it?

thanks


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