ps。別のポイントをカバーするために2番目の回答を追加します。両方の詳細を保持したいすべての場所に Organization_ID と Person_ID を配置するのではなく、各組織と個人に一意の ID を提供する Party というテーブルを作成し、それを Organization/Person レコードに関連付けます。これで、個人 ID と組織 ID を関連付けたい任意のテーブルに 1 つの列を使用するだけで済みます。
これは、パーティ パターンまたはパーティ モデルとして知られる OO (オブジェクト指向) の世界の一般的なパターンです (詳細については、これらの用語を Google で検索してください)。
これがどのように機能するかをよりよく理解するために、以下のサンプルコードを見て/遊んでください/質問があれば、私に声をかけてください:
/* 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