IBBlob

Use TIBBlobStream to access or modify the value of a Blob field object. Blob field objects are TBlobField objects and descendants of TBlobField such as TGraphicField and TMemoField. Blob fields use Blob streams to implement many of their data access properties and methods. 

TIBBlobStream allows objects that have no specialized knowledge of how data is stored in a Blob field to read or write such data by employing the uniform stream interface. 

To use a Blob stream, create an instance of TIBBlobStream, use the methods of the stream to read or write the data, and then free the Blob stream. Do not use the same instance of TBlobStream to access data from more than one record. Instead, create a new TIBBlobStream object every time you need to read or write Blob data on a new record.