Property Types
Note
Indexing Service is no longer supported as of Windows XP and is unavailable for use as of Windows 8. Instead, use Windows Search for client side search and Microsoft Search Server Express for server side search.
Each document property represents either unformatted text or a formatted value. Thus, each property is said to be either a text-type or a value-type property. Text-type properties describe the possibly complex content of a document. Value-type properties describe a single property of the entire document.
A text-type property has only unformatted text associated with its name. A value-type property has a data type ID and a value of that data type associated with its name. The data type ID can be textual (for example, VT_LPWSTR) or non-textual (for example, VT_I8). If a value-type property is cached, it also has an associated cached size and a storage level, which is either primary or secondary. For details about caching and storage level, see Property Indexing.
The following table gives either the friendly name or the PROPSPEC string name of several properties and fills in the details appropriate for each property type.
| Name | Type | Data Type Identifier | Cached Size | Storage Level |
|---|---|---|---|---|
| Contents | Text | – | – | – |
| Size | Value (non-textual) | VT_I8 | 8 bytes | Secondary |
| DocTitle | Value (textual) | VT_LPWSTR | 4 bytes | Secondary |
| "description" | Value (textual) | VT_LPWSTR | 4 bytes | Secondary |
| HtmlHeading1 | Text | – | – | – |
The text-type property named Contents is a special case. It corresponds to the main body of unformatted text in a document. A document can have any number of instances of text-type properties with the same name (and typically might have many words associated with the Contents property). However, a processed document can retain the value from only one instance (usually the one encountered last) of a value-type property with a specific name.
The type of a document property determines how Indexing Service indexes the property and the kind of querying Indexing Service can perform with the property. For details about indexing, see Property Indexing, and for details about querying, see Property Querying.