ISequentialStream

ISequentialStream is the preferred minimal interface for reading and writing binary large object (BLOB) data in OLE DB. ISequentialStream is a subset of the COM IStream interface and provides forward-only reading and writing of data. The IStream interface inherits its Read and Write methods from ISequentialStream.

When to Implement

You can implement ISequentialStream on an object if you require simple sequential access to a stream object. If you implement IStream, you must provide an implementation of the Read and Write methods from ISequentialStream.

Note

Most applications do not implement ISequentialStream as a separate interface, and it is not required to provide it separately even when an IStream implementation is provided. For example, the compound file implementation of structured storage does not succeed on a QueryInterface for ISequentialStream but it includes the Read and Write methods through the IStream interface pointer.

When to Call

Call the methods of the ISequentialStream interface from a container or application to perform sequential reads and writes of data. Most applications call the Read and Write methods through the IStream interface.

Methods in Vtable Order

IUnknown Methods	Description
QueryInterface	Returns pointers to supported interfaces.
AddRef	Increments the reference count.
Release	Decrements the reference count.

ISequentialStream Methods	Description
ISequentialStream::Read	Reads a specified number of bytes from the stream object into memory, starting at the current seek pointer.
ISequentialStream::Write	Writes a specified number of bytes to the stream object, starting at the current seek pointer.

This topic is a part of:

• Microsoft OLE DB