1-1 relation - SQL Server Forums

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1-1 relation

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Topic

happynnc
Starting Member

7 Posts

Posted - 2012-08-26 : 23:08:45

Hello everyone,

I am starting to study DB, and I read on the document that: "having two separate tables in a one-to-one relationship is considered bad practice."

But I have a requirement of designing of CUSTOMER as below:
- Customer have Membership Card ID
- Membership Card depends on Customer Type

So that I create 3 tables as below:

- Customer table (Customer_ID, Customer_FirstName, Customer_LastName, Customer_Address, Customer_City, Customer_Phone, Customer_Email, Membership Card) | Customer ID = PK

- Membership Card (MemberCard_ID, MemberCard_Type, MemberCard_IssueDate) | MemberCard_ID = PK

- Membership Type (MembershipType_ID, MembershipType_Description, MembershipType_Discount) | MembershipType_ID = PK

So, the Membership Type have 1-Many with Membership Card
And, Customer have 1-1 with Membership Card

In my mind, I think it ok, but because the lecture show that 1-1 is not good for DB design. How can I make my 3 table better design?

Thanks,

chadmat
The Chadinator

1974 Posts

Posted - 2012-08-26 : 23:52:06

Looks correct to me, not sure why this would be bad practice?

-Chad

happynnc
Starting Member

7 Posts

Posted - 2012-08-27 : 00:07:17

Thanks Chadmat :)

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