Question

I have two tables in my sql:

Users :

id    name     roleid
1     David    1
2     Sean     2
3     Joe      1

Roles:

roleid    desc
1         copy
2         delete
3         move

Now i use this cmd to select the user with the user permission

SELECT * FROM Users u INNER JOIN Roles r ON u.roleid = r.roleid

Now i want to know if it’s possible to build SQL Table(Roles Table), that it’s will be dynamically the number of roleid for each user. something like:

Users :

id    name     roleid roleid2 roleid3
1     David    1      2       3
2     Sean     2   
3     Joe      1      3

Answer 1

Use an associative entity to address the many-to-many relationship between Users and Roles. A composite primary key in the UserRole table will prevent duplicate assignment of roles, and foreign keys referencing the Users and Roles table will preserve referential integrity.

See SQL fiddle for a sample implementation.