Overview of the Connection Process

Context for making a connection

Chapter 1 describes the software components that are involved when your application accesses data through the OLAP API. A review of the interaction among the components can be helpful in understanding what happens when your application establishes a connecton. The following steps describe a typical interaction among the components:

1. The application code makes a request for data by calling the OLAP API client software.

2. The OLAP API client software makes a call to the CORBA software, which passes the request to the OLAP service.

3. The OLAP service retrieves data from the Oracle database and performs the selections or calculations specified by the application.

4. The OLAP service fulfills the data request by passing the data to the application through the CORBA and OLAP API software.

What happens when you open a connection

When your application establishes a connection, the following events take place:

1. At the request of the application, the CORBA software establishes a connection between the application and the particular OLAP service that the application specified.

2. On behalf of the application, the OLAP service establishes a connection with its parent Oracle database instance. The connection is made with the user ID and password that were specified by the application. The scope of the data that is available to the application depends on the access rights assigned to the user ID.

Note that once the connection is established, your application can access the data store or it can access an analytic workspace, which is managed separately by the OLAP service. For more information about accessing an analytic workspace, see Oracle9i OLAP Services Developer's Guide to the OLAP DML.

Prerequisites for connecting

This chapter describes the OLAP API classes and methods that an application uses to establish a connection. Before attempting to use these classes and methods, you must ensure that your development environment is set up correctly. The development environment includes the application development computer, on which your OLAP API application will run, as well as the computer on which the OLAP service is running.

Ensure that your development environment meets the following requirements:

• The Oracle database and the OLAP service are running. Note that when the OLAP service is running, the CORBA software on the OLAP service computer is ready to accept connections.

• Your Oracle database user ID has access to the relational schemas on which the data store is based, and the user ID is set up to connect to the database through the OLAP service.

• The CORBA software is in place and ready to run on the application development computer.

• The OLAP API jar files are on the application development computer and are accessible to the application code.

See Appendix A for information about the OLAP API jar files and the CORBA software for the application development computer. For information about setting up a user ID to connect through an OLAP service, see the Oracle9i OLAP Services Concepts and Administration Guide.

Coding steps for making a connection

To make a connection, perform the following steps:

1. Get a CORBA stub that represents the OLAP service to which the connection will be made.

2. Create a Properties object and put into it all the connection parameters that are required. For example, include the Oracle database user ID and password.

3. Make the connection by calling a method on one of the OLAP API connection classes, which are described in "Connection Classes in the OLAP API".

These steps are explained in more detail in the topic "Establishing a Connection".

OLAP API classes involved in making a connection

You use the following OLAP API classes to make a connection:

• ConnectionManager class

• Connection class

• ConnectionParameterInfo class

These classes are described in more detail in the topic "Connection Classes in the OLAP API". In addition to these OLAP API classes, you use CORBA classes, as described in "Step 1: Getting the CORBA stub for the first connect method parameter".