db4o |

# ExtObjectContainer.GetID Method

returns the internal unique object ID.

long GetID(
object obj
);

#### Parameters

obj
  any object

#### Return Value

the associated internal ID or

    0

, if the passed object is not stored in this

    ObjectContainer

.

#### Remarks

returns the internal unique object ID.
db4o assigns an internal ID to every object that is stored. IDs are guaranteed to be unique within one

    ObjectContainer

. An object carries the same ID in every db4o session. Internal IDs can be used to look up objects with the very fast getByID method.
Internal IDs will change when a database is defragmented. Use com.db4o.ext.ExtObjectContainer.GetObjectInfo , com.db4o.ext.ObjectInfo.GetUUID and com.db4o.ext.ExtObjectContainer.GetByUUID for long-term external references to objects.

#### See Also

ExtObjectContainer Interface | com.db4o.ext Namespace