Icon TEDBBlobStream

Header File: edbcomps

Inherits From Classes

Use the TEDBBlobStream object to access or modify the contents of a BLOB or CLOB column in a dataset using a stream interface. A BLOB column is represented by the TBlobField object, and a CLOB column is represented by a TMemoField object. TBlobField and TMemoField objects use streams to implement many of their data access properties and methods via the standard CreateBlobStream method that is implemented by the ElevateDB dataset components.

To use a TEDBBlobStream object, create an instance of TEDBBlobStream, use the methods of the TEDBBlobStream object to read or write the data, and then free the object. Do not use the same instance of a TEDBBlobStream object to access data from more than one row. Instead, create a new TEDBBlobStream object every time you need to read or write to a BLOB or CLOB column for a row.

Information For proper results when updating a BLOB or CLOB column using a TEDBBlobStream object, you must create the TEDBBlobStream object after calling the Append/Insert or Edit method for the dataset containing the BLOB or CLOB column. Also, you must free the TEDBBlobStream object before calling the Post method to post the changes to the dataset. Finally, be sure to use the proper open mode when creating a TEDBBlobStream object for updating (either bmReadWrite or bmWrite).


PropertiesMethodsEvents
Read
Seek
TEDBBlobStream
Truncate
Write
Image