附言。添加第二个答案以涵盖另一点。与其在任何地方都使用 Organisation_ID 和 Person_ID 来保存两者的详细信息，不如创建一个名为 Party 的表，它为每个组织和个人提供唯一的 id - 然后将其与 Organization/Person 记录相关联。现在，您可以简单地将一列用于您希望能够关联个人 ID 和组织 ID 的任何表。
这是一种来自 OO（面向对象）世界的常见模式，称为派对模式或派对模型（谷歌这些术语以了解更多信息）。
看看/玩下面的示例代码，以更好地了解它是如何工作的/有任何问题请给我留言：
/* setup */
if OBJECT_ID('Registrations') is not null drop table Registrations
if OBJECT_ID('PartyContact') is not null drop table PartyContact
if OBJECT_ID('ContactType') is not null drop table ContactType
if OBJECT_ID('Organisation') is not null drop table Organisation
if OBJECT_ID('Person') is not null drop table Person
if OBJECT_ID('Party') is not null drop table Party
go
create table ContactType
(
contactType_id int not null identity(1,1) constraint PK_ContactType primary key clustered
, name nvarchar(16) not null constraint UK_ContactType_Name unique
)
go
set identity_insert ContactType on
insert ContactType (contactType_id, name)
select 1, 'WorkEmail'
union select 2, 'PersonalEmail'
union select 3, 'Mobile/Cell'
set identity_insert ContactType off
go
create table Party
(
party_id bigint not null identity(1,1) constraint PK_Party primary key clustered
, name nvarchar(256) not null --this is duplicating the name on the Person/Organisation tables; normally this denormalisation would be bad practice, but here it assists in making data available in the table from which it will be referenced
--any other attributes which you want to be common to all parties
)
go
set identity_insert Party on
insert Party (party_id, name)
select 12, 'Rob Ottow'
union select 13, 'Ann Droid'
union select 14, 'Si Bermann'
union select 112, 'Global Mega Org'
union select 113, 'GeoTech Solutions'
union select 114, 'Think Ink inc.'
set identity_insert Party off
go
create table Person
(
person_id bigint not null identity(1,1) constraint PK_Person primary key clustered
, name nvarchar(256) not null
, party_id bigint not null constraint FK_Person_PartyId references Party(party_id)
constraint UK_Person_PartyId unique
, dob date
)
go
set identity_insert Person on
insert Person (person_id, name, party_id, dob)
select 2, 'Rob Ottow' , 12, '1984-12-25'
union select 3, 'Ann Droid' , 13, null --it's impolite to give a woman's age
union select 4, 'Si Bermann', 14, '1973-06-12'
set identity_insert Person off
go
create table Organisation --en-gb spelling since that's where I'm from
(
organisation_id bigint not null identity(1,1) constraint PK_Organisation primary key clustered
, name nvarchar(256) not null
, party_id bigint not null constraint FK_Organisation_PartyId references Party(party_id)
, taxNumber nchar(12) not null
)
go
set identity_insert Organisation on
insert Organisation (organisation_id, name, party_id, taxNumber)
select 1, 'Global Mega Org' , 112, '123456789012'
union select 2, 'GeoTech Solutions' , 113, '012345678901'
union select 3, 'Think Ink inc.' , 114, '901234567890'
set identity_insert Organisation off
go
create table PartyContact
(
partyContact_id bigint not null identity(1,1) constraint PK_PartyContract primary key clustered
, party_id bigint not null constraint FK_PartyContract_PartyId foreign key references Party(party_id)
, contactDetails nvarchar(256) not null
, contactType_id int not null constraint FK_PartyContract_ContactTypeId foreign key references ContactType(contactType_id)
)
go
set identity_insert PartyContact on
insert PartyContact (partyContact_id, party_id, contactDetails, contactType_id)
select 1 ,112 ,'O12@EMAIL.COM' ,1
union select 2 ,12 ,'P12@EMAIL.COM' ,1
union select 3 ,13 ,'P13@EMAIL.COM' ,1
union select 4 ,14 ,'P14@EMAIL.COM' ,1
union select 5 ,113 ,'O13@EMAIL.COM' ,1
union select 6 ,14 ,'P14_p@EMAIL.COM' ,2
union select 7 ,114 ,'O14@EMAIL.COM' ,2
union select 8 ,13 ,'P13_2@EMAIL.COM' ,1
union select 9 ,13 ,'01234 567890' ,3
set identity_insert PartyContact off
go
create table Registrations
(
registration_id bigint not null identity(1,1) constraint PK_Registrations primary key clustered
, party_id bigint not null constraint FK_Registrations_PartyId references Party(party_id)
, name nvarchar(32) not null
, registration_Date date not null
)
go
set identity_insert Registrations on
insert Registrations (registration_id, party_id, name, registration_Date)
select 1 ,112 ,'ORG12' ,'10/05/2013'
union select 2 ,12 ,'P12' ,'10/05/2013'
union select 3 ,13 ,'P13' ,'10/05/2013'
union select 4 ,14 ,'P14' ,'10/05/2013'
union select 5 ,113 ,'O13' ,'10/05/2013'
union select 6 ,114 ,'O14' ,'10/05/2013'
set identity_insert Registrations off
go
/* get the results */
SELECT r.registration_id, r.party_id, p.person_id, o.organisation_id, r.name, c.contactDetails
FROM Registrations r
left outer join Person p on p.party_id = r.party_id
left outer join Organisation o on o.party_id = r.party_id
left outer join
(
select party_id, contactDetails
from PartyContact a
inner join
(
select MIN(partyContact_id) partyContact_id
from PartyContact
where contactType_id in (select contactType_id from ContactType where name = 'WorkEmail')
group by party_id
) b
on a.partyContact_id = b.partyContact_id
) c
ON r.party_id = c.party_id