# One-to-One Mapping

Property | Description | Default
--- | --- | ---
Target entity | The persistent entity to which the attribute is mapped. |

Fetch

Defines how data is loaded from the database:

- Eager – Data is loaded in before it is actually needed.

- Lazy – Data is loaded only when required by the transaction.

Eager

Join fetch

The type of fetch to use:

- Inner – Provides the inner join fetching of the related object.

  Note: Inner joining does not allow for null or empty values

- Outer – Provides the outer join fetching of the related object

  Note: Outer joining allows for null or empty values.

Optional | Specifies if this field is can be null. | True
Private owned | Specify that a relationship is privately owned; target object is a dependent part of the source object and is not referenced by any other object and cannot exist on its own. | False
Orphan removal |  | False

Cascade

Specify which operations are propagated throughout the entity.

- All – All operations

- Persist

- Merge

- Move

- Remove

- Refresh

True

One-to-one mappings also include the following areas:

- Derived Identity

- Joining Strategy