[This is preliminary documentation and subject to change.]
The summary information stream is very convenient for storing information that can be viewed with Microsoft® Windows® Explorer. Microsoft® Windows® installer sets the summary information stream properties by default. The default value for each type of database is described in this section. The installer uses certain database and summary properties to populate the summary information stream for a database.
The summary information stream uses COM to provide structured storage of databases. COM supports the concept of structured storage accessible through the IStream interface. Structured storage, in turn, supports the concept of property sets as a flexible method for serializing almost any information. The COM specification defines a single standard property set, summary information, which is used to populate property sheets viewable from the Windows Explorer. So, information stored in the summary information stream can be viewed by users when they right-click an installer database or transform and select Properties.
Note When a database is opened as the output of another database, the summary information stream of the output database is actually a read-only mirror of the original database and thus cannot be changed. Additionally, it will not be persisted with the database. To create or modify the summary information for the output database it must be closed and re-opened.