5. OLE-DB Client Provider

5.3. Provider Specific Connection Information

OLE DB predefines a number of property sets and the properties in them. The Extended Properties property in the Initialization property group provides a means of supplying provider-specific extended connection information. The OpenLink provider supports extended properties to control:

• ODBC Cursor Library usage
• whether bookmarks are enabled by default on rowsets

There are three ways to enter extended properties:

• Through a prompting interface supplied by the consumer application.
• Initialise a Data Source object through a connection string.
• Explicitly set the DBPROP_INIT_PROVIDERSTRING property in the consumer application code.

5.3.1. Using a Consumer Supplied Prompting Interface

The OpenLink provider does not display a prompting interface of its own for entering OLE DB specific connection information. It relies instead upon the application supplying it.

OLE DB provides several core components, one of which is the Data Link component. The Data Link component provides a default prompting interface and is used by numerous Microsoft applications. It typically includes a page displayed by the ‘All’ tab, which allows users to set values for all the Initialization properties supported by an OLE DB provider. The ‘Extended Properties’ property can be set on this page. For the OpenLink provider, you should enter key-value pairs for any supported extended properties you wish to set, such as:

”Cursors=Driver”

5.3.2. Using a Connection String

The connection string is used to contain connection specific details as semi-colon delimited key=value pairs so that the Broker/Agent facilitating the connection can chose the correct database and method. The details provided on various setup panels form the connect string automatically upon use. Applications can use hand made connection strings to avoid DSN configurations or prompting during exection. The parameters that can be used are as follows:

The connection string should contain a key-value pair for the “Extended Properties” keyword, such as:

• PROVIDER=OpenLinkODBC
• DRIVER={OpenLink Generic 32 Bit driver v4.0}
• HOST=BrokerHostNameOrIP
• PORT=BrokerListenPort
• SVT=DBMSType/Provider
• DATABASE=myDatabaseName
• UID=myUsername
• PWD=myPassword
• PROTOCOL=TCP/IP
• FBS=FetchBufferSize (Rows 1-99)
• DLF=DeferLongFetch [y|n]
• OPTIONS=opts
• READONLY=[y|n]
• DSN=myDSNname

 …;Extended Properties=”Cursors=ODBC”;… 

Which is used for setting the cursor mode and/or bookmarking.

5.3.3. Using The DBPROP_INIT_PROVIDERSTRING Property

Applications can set this initialization property directly.