| ADO 2.5 |  |
Records and Provider-Supplied Fields
When a Record object is opened, its source can be the current row of an open Recordset, an absolute URL, or a relative URL in conjunction with an open Connection object.
If the Record is opened from a Recordset, the Record object Fields collection will contain all the fields from the Recordset, plus any fields added by the underlying provider.
The provider may insert additional fields that serve as supplementary characteristics of the Record. As a result, a Record may have unique fields not in the Recordset as a whole or any Record derived from another row of the Recordset.
For example, all rows of a Recordset derived from an e-mail data source might have columns such as From, To, and Subject. A Record derived from that Recordset will have the same fields. However, the Record may also have other fields unique to the particular message represented by that Record, such as Attachment and Cc (carbon copy).
Although the Record object and current row of the Recordset have the same fields, they are different because Record and Recordset objects have different methods and properties.
A field held in common by the Record and Recordset can be modified on either object. However, the field cannot be deleted on the Record object, although the underlying provider may support setting the field to null.
After the Record is opened, you can programmatically add fields. You can also delete fields you have added, but you cannot delete fields from the original Recordset.
You may also open the Record object directly from a URL. In this case, the fields added to the Record depend on the underlying provider. Currently, most providers add a set of fields that describe the entity represented by the Record. If the entity consists of a stream of bytes, such as a simple file, then a Stream object can usually be opened from the Record.
Special Fields for Document Source Providers
A special class of providers, called document source providers, manages folders and documents. When a Record object represents a document or a Recordset object represents a folder of documents, the document source provider populates those objects with a unique set of fields that describe characteristics of the document instead of the actual document itself. Typically, one field contains a reference to the Stream that represents the document.
These fields constitute a resource record or recordset and are listed for the specific providers that support them in Appendix A: Providers.
Two constants index the Fields collection of a resource Record or Recordset to retrieve a pair of commonly used fields. The Field object Value property returns the desired content.
- The field accessed with the adDefaultStream constant contains a default stream associated with the Record or Recordset object. The provider assigns a default stream to an object.
- The field accessed with the adRecordURL constant contains the absolute URL that identifies the document.
A document source provider does not support the Properties collection of Record and Field objects. The content of the Properties collection is null for such objects.
A document source provider may add a provider-specific property such as Datasource Type to identify whether it is a document source provider. For more information about how to determine your type of provider, see your provider documentation.
Resource Recordset Columns
A resource recordset consists of the following columns.
| Column name | Type | Description |
|---|---|---|
| RESOURCE_PARSENAME | AdVarWChar | Read-only. Indicates the URL of the resource. |
| RESOURCE_PARENTNAME | AdVarWChar | Read-only. Indicates the absolute URL of the parent record. |
| RESOURCE_ABSOLUTEPARSENAME | AdVarWChar | Read-only. Indicates the absolute URL of the resource, which is the concatenation of PARENTNAME and PARSENAME. |
| RESOURCE_ISHIDDEN | AdBoolean | True if the resource is hidden. No rows will be returned unless the command that creates the rowset explicitly selects rows where RESOURCE_ISHIDDEN is True. |
| RESOURCE_ISREADONLY | AdBoolean | True if the resource is read-only. Attempts to open this resource with DBBINDFLAG_WRITE and will fail with DB_E_READONLY. This property may be edited even when the resource has only been opened for reading. |
| RESOURCE_CONTENTTYPE | AdVarWChar | Indicates the likely use of the document—for example, a lawyer's brief. This may correspond to the Office template used to create the document."" |
| RESOURCE_CONTENTCLASS | AdVarWChar | Indicates the MIME type of the document, indicating the format such as "text/html".' |
| RESOURCE_CONTENTLANGUAGE | AdVarWChar | Indicates the language in which the content is stored. |
| RESOURCE_CREATIONTIME | adFileTime | Read-only. Indicates a FILETIME structure containing the time the resource was created. The time is reported in Coordinated Universal Time (UTC) format. |
| RESOURCE_LASTACCESSTIME | AdFileTime | Read-only. Indicates a FILETIME structure containing the time that the resource was last accessed. The time is in UTC format. The FILETIME members are zero if the provider does not support this time member. |
| RESOURCE_LASTWRITETIME | AdFileTime | Read-only. Indicates a FILETIME structure containing the time that the resource was last written. The time is in UTC format. The FILETIME members are zero if the provider does not support this time member. |
| RESOURCE_STREAMSIZE | asUnsignedBigInt | Read-only. Indicates the size of the resource's default stream, in bytes. |
| RESOURCE_ISCOLLECTION | AdBoolean | Read-only. True if the resource is a collection, such as a directory. False if the resource is a simple file. |
| RESOURCE_ISSTRUCTUREDDOCUMENT | AdBoolean | True if the resource is a structured document. False if the resource is not a structured document. It could be a collection or a simple file. |
| DEFAULT_DOCUMENT | AdVarWChar | Read-only. Indicates that this resource contains a URL to the default simple document of a folder or a structured document. Used when the default stream is requested from a resource. This property is blank for a simple file. |
| CHAPTERED_CHILDREN | AdChapter | Read-only. Optional. Indicates the chapter of the rowset containing the children of the resource. (The OLE DB Provider for Internet Publishing does not use this column.) |
| RESOURCE_DISPLAYNAME | AdVarWChar | Read-only. Indicates the display name of the resource. |
| RESOURCE_ISROOT | AdBoolean | Read-only. True if the resource is the root of a collection or structured document. |
See Also
Record Object | Appendix A: Providers