Call CreateBlobStream to obtain a stream for reading data from or writing data to a binary large object (BLOB) field. The Field parameter must specify a TBlobField component from the Fields property array. The Mode parameter specifies whether the stream will be used for reading, writing, or updating the contents of the field. 

Blob streams are created in a specific mode for a specific field on a specific record. Applications should create a new blob stream every time the record in the dataset changes rather than reusing an existing blob stream. 

Fields 

TBlobStream