[英]How to bind users to different organizations, universities, companies with different roles?
USERS
1. GFER: SUPERADMIN
Foundation(VAG):
2. John: Incharge
3. Jessi: IT Head
University(MIT):
4: Bill: Adminstrator
5: Gates: Prinicipal investigator
6: Donald: Researcher
Organizations(YE):
6. Jason: Head of R&D
7. Johnny: Researcher
University, organization or company can't exist without a user.没有用户,大学、组织或公司就无法存在。 There would always exist a user who'll create it or own it.
总会存在一个创建或拥有它的用户。 And every user would have a personal profile as well.
每个用户也会有一个个人资料。
Schema looks like this:架构如下所示:
User用户
- email
- name
Roles:角色:
- id
- name
University(Profile):大学(简介):
- name
- short history
Organizatons(Profile):组织机构(简介):
- name
- logo of the brand
Foundation(Profile):基金会(简介):
- name
- Adminstrative contacts
How can i know a user is bind to which table(foundation, organization or university) and what role does it have in that group(foundation, organization or university)?我如何知道用户绑定到哪个表(基金会、组织或大学)以及它在该组(基金会、组织或大学)中的角色? I thought to create a bridge table like this:
我想像这样创建一个桥接表:
Group:
- id
- name
- type(University, Foundation, Organization)
Group_members:
- id
- roleId
- groupId
- userId
But the problem is that i can't create a groups
table as data for university, foundation and organization is totally different for each other.但问题是我无法创建
groups
表,因为大学、基金会和组织的数据彼此完全不同。 So i'll have to create a separate table for each.所以我必须为每个人创建一个单独的表。 How can i solve this problem?
我怎么解决这个问题?
-- User USR exists.
--
user {USR}
PK {USR}
-- Role ROL exists.
--
role_ {ROL}
PK {ROL}
Xorg
is a generic term for a university, an organization, or a foundation. Xorg
是大学、组织或基金会的通用术语。 Discriminator TYP
is used to distinguish between these three.鉴别器
TYP
用于区分这三者。
-- Xorg XOG, of type TYP, named XNM was created
-- (is owned) by user USR.
--
xorg {XOG, TYP, USR, XNM, ...common_cols}
PK {XOG}
SK {XOG, TYP}
CHECK TYP in {'U', 'O', 'F'}
FK {USR} REFERENCES user {USR}
-- University (xorg) XOG, of xorg-type TYP = 'U', exists.
--
university {XOG, TYP, ...university_specific_cols}
PK {XOG}
CHECK TYP = 'U'
FK {XOG, TYP} REFERENCES xorg {XOG, TYP}
-- Organization (xorg) XOG, of xorg-type TYP = 'O', exists.
--
organization {XOG, TYP, ...organization_specific_cols}
PK {XOG}
CHECK TYP = 'O'
FK {XOG, TYP} REFERENCES xorg {XOG, TYP}
-- Foundation (xorg) XOG, of xorg-type TYP = 'F', exists.
--
organization {XOG, TYP, ...foundation_specific_cols}
PK {XOG}
CHECK TYP = 'F'
FK {XOG, TYP} REFERENCES xorg {XOG, TYP}
-- User USR is member of xorg XOG, of xorg-type TYP,
-- in role ROL.
--
user_xorg {USR, XOG, TYP, ROL}
PK {USR, XOG}
FK1 {XOG, TYP} REFERENCES
xorg {XOG, TYP}
FK2 {USR} REFERENCES user {USR}
FK3 {ROL} REFERENCES role_ {ROL}
Note:笔记:
All attributes (columns) NOT NULL
PK = Primary Key
AK = Alternate Key (Unique)
SK = Proper Superkey (Unique)
FK = Foreign Key
A word about subtypes .关于子类型的一句话。 The proper way to implement constraints for subtypes would be to use assertions (
CREATE ASSERTION
), but it is still not available in major DBs.为子类型实现约束的正确方法是使用断言(
CREATE ASSERTION
),但它在主要数据库中仍然不可用。 I am using FKs
instead, and as all other substitute methods it is not perfect.我改用
FKs
,与所有其他替代方法一样,它并不完美。 People argue a lot, on SO and SE-DBA, what is better.人们争论很多,关于 SO 和 SE-DBA,什么更好。 I encourage you to check other methods too.
我鼓励您也检查其他方法。
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