One-to-One Relationship

Definition - What does One-to-One Relationship mean?

A one-to-one relationship in a relational database occurs when one parent record or field has either zero or one child record only. These relationships are the easiest to represent in databases because both the parent and child records may be in the same table.

Techopedia explains One-to-One Relationship

As an example, in the CUSTOMER_MASTER table in a bank’s database, each customer is represented by a unique CUSTOMER_ID, which is also the table’s primary key. Each customer may also have a government issued social security card, which contains a unique social security number. Therefore, each customer must have a single customer ID in the bank’s database. If a customer does have one, then there can only be one social security number per customer.

The parent field (CUSTOMER_ID) has a one-to-one relationship with the social security field. For such relationships, it is best to put them into one table for ease of reference. In this case, the social security number should simply be an additional column in the CUSTOMER_MASTER table.

Share this:

Connect with us

Email Newsletter

Join thousands of others with our weekly newsletter

The 4th Era of IT Infrastructure: Superconverged Systems
The 4th Era of IT Infrastructure: Superconverged Systems:
Learn the benefits and limitations of the 3 generations of IT infrastructure – siloed, converged and hyperconverged – and discover how the 4th...
Approaches and Benefits of Network Virtualization
Approaches and Benefits of Network Virtualization:
Businesses today aspire to achieve a software-defined datacenter (SDDC) to enhance business agility and reduce operational complexity. However, the...
Free E-Book: Public Cloud Guide
Free E-Book: Public Cloud Guide:
This white paper is for leaders of Operations, Engineering, or Infrastructure teams who are creating or executing an IT roadmap.
Free Tool: Virtual Health Monitor
Free Tool: Virtual Health Monitor:
Virtual Health Monitor is a free virtualization monitoring and reporting tool for VMware, Hyper-V, RHEV, and XenServer environments.
Free 30 Day Trial – Turbonomic
Free 30 Day Trial – Turbonomic:
Turbonomic delivers an autonomic platform where virtual and cloud environments self-manage in real-time to assure application performance.