A JADE object comprises an instance of each property defined in the associated JADE class. In general, the following two groups of properties may be required.
Any simple properties, such as Integer, Boolean, and references to other objects. This includes Binary and String properties with a specified length.
Any maximum‑length Binary and String properties (Blobs and Slobs, respectively).
In the JADE journal, all simple primitive type properties are grouped into the record known as the object's journal record, identified by the OID. To uniquely identify the actual version of the object, the OID is supplemented by an edition number that is incremented each time the object is modified.
The 'parent' object record contains the length and edition of the Blob/Slob. You can retrieve this Blob/Slob information while you are accessing the parent object journal record. You can determine whether any Blob/Slob value has changed by comparing the edition number from the before‑image with the edition number from the after‑image. The Blob/Slob property value is not written to the journal if it has not changed.
Each of the Blob or Slob property values is written separately to the journal. The Blob/Slob OID contains sufficient information to identify the parent object OID, and the actual property within that object.
When the Blob/Slob record is encountered in the journal, a Blob‑ or Slob‑type journal record is returned from the
Remember the following points.
Blob/Slob records can be either before or after the parent object record.
Blob/Slob records are written to the journal only if they are changed.
Parent object records are written to the journal if a Blob or Slob has changed.