The Metabase Schema File

Our discussion of the metabase schema file MBSchema.xml will be brief because modifying the schema is rarely needed and requires advanced understanding of XML syntax. The purpose of the schema is to define the properties that can be used in the metabase configuration file MetaBasd.xml and also to enforce the data type for such in-schema properties.

Like MetaBase.xml, the schema is written to memory when IIS starts and periodically flushed to disk whenever changes occur in either file. The format for the schema is different, however, and consists of a number of containers called collections that contain configuration objects defining metabase properties. Here is a small portion of the collection named IIsConfigObject showing a single property called AnonymousUserName (IIsConfigObject has more than 100 such properties):

<Collection   InternalName ="IIsConfigObject"               MetaFlagsEx="NOTABLESCHEMAHEAPENTRY"               MetaFlags="HASUNKNOWNSIZES | HIDDEN               > ... <Property     InternalName ="AnonymousUserName"                                        Type="STRING"               UserType="IIS_MD_UT_FILE"               Attributes="INHERIT"               MetaFlagsEx="CACHE_PROPERTY_MODIFIED"               DefaultValue=""               > ... </Collection>

For more information on the metabase schema and how to interpret and extend it, see IIS Help.