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Model Question

Model Question# Database - 数据库

C*n2003-10-08 07:10

1 楼

Table:
User: UserID,...
Portal: PortalID,...
Role: RoleID, PortalID, ....
UserRole: UserID, RoleID
Question: Is this model 3NF? if not how to change it?
My problem is that: I want to constraint a User should belong to a paticular
portal. But right now, a User doesn't belong to any portal if he doesn't have
any ROLE associated, and I don't want a user has role from more than 1 portal.
Thanks,
Calvin

s*e2003-10-08 07:10

2 楼

The definition of 3rd normal form is:
A relation that is in first and second normal form, and in which no
non-primary-key
attribute is transitively dependent on the primary key.
I think you need to create a new table user_portal, which has userid and
portalid.

have
portal.

【在 C****n 的大作中提到】

: Table:
: User: UserID,...
: Portal: PortalID,...
: Role: RoleID, PortalID, ....
: UserRole: UserID, RoleID
: Question: Is this model 3NF? if not how to change it?
: My problem is that: I want to constraint a User should belong to a paticular
: portal. But right now, a User doesn't belong to any portal if he doesn't have
: any ROLE associated, and I don't want a user has role from more than 1 portal.
: Thanks,