ADOMD.NET - Microsoft SQL Server 2008 Analysis Services - page 600

All the properties supported by ADOMD.NET fall into two categories:

. Properties necessary for establishing a connection with a server and that have to be,

consequently, processed by ADOMD.NET on the client. An example from this cate-
gory is the property Datasource , which contains the name of a source of data.

. Properties responsible for various operations on the server and that, therefore, must

be sent to the server. An example from this category is the property Initial
Catalog , which contains the name of the database on the server.

During the execution of the method Open , ADOMD.NET parses the content of the
ConnectionString property and separates the properties into two groups: those that will
be used on the client, and those that will be packed in an XML for Analysis (XML/A)
message and sent to the server. Then, ADOMD.NET analyzes the content of the
Datasource property and, depending on the content, chooses a type of connection to a
data source and opens it. Table 33.1 shows the possible content of the Datasource prop-
erty and the type of connection that would be opened.

TABLE 33.1 Datasource Property Content and Corresponding Connections
Content of the Datasource Property Connection

Filename with the extension .cub Connection with a local cube

URL beginning with http:// or https:// HTTP connection

Name (or IP address) of a computer or instance TCP/IP connection

TCP/IP connection to the same computer

local or localhost

Analysis Services supports multiple servers working on one computer (multi-instancing).
Each instance listens on a different port. If you're connecting to a multi-instancing
computer via TCP/IP, you cannot use just the name of the computer for the name of the
server.

If a user is connecting to a computer running multiple instances, she has to use the name
of the instance in addition to the name or IP address of the computer. If she is connect-
ing to the default instance, she can use just the name (or IP address) of the computer—
localhost or local if the client and server are on the same computer. ADOMD.NET
would use the following BNF (Backus-Naur Form notation) to parse the content of the
Datasource property:

Datasource::= <host name>[\instance name |: port number]
<host name>::= <computer name>|<IP address> | localhost | local

If the user knows on which port the instance listens, she can specify the port number—for
example, Datasource = localhost:1092 . But more often, the user doesn't know the port
number, but she does know the name of the instance. So, she would specify the name of
the instance—for example, Datasource = localhost\myinstance . In such a case,
ADOMD.NET carries out a more complex operation. It sends a Discover_Instances
request for the port number of the Redirector, with restrictions on the name of the