Overview of the Tasks to Set Up a Federated System

This section describes the tasks required to establish and use a federated system. Although the tasks identify the types of users who typically execute the tasks, other types of users can also perform these tasks. To establish and use a DB2 federated system:

System Administrator:

  1. Determines and designates a server as a DB2 federated server

  2. Installs and configures the data source client software and links DB2 to the client software

  3. Installs DB2 and creates the DB2 instance

  4. Installs DB2 Relational Connect (if necessary)

Database Administrator:

  1. Creates a wrapper for each category of data source that is to be included in the federated system

  2. Supplies the federated server with a server definition for each data source and might supply server options to assist in optimizing distributed requests

  3. Defines an association between the authorization IDs that are used to access the federated database and the authorization IDs that are used to access a data source

  4. Creates nicknames for the data source objects that are to be accessed

Application Programmers/End Users:

  1. Retrieves information from data sources:

    • Using the DB2 SQL dialect, application programmers and end users submit queries using the nicknames associated with the data source objects.

    • Application programmers and end users occasionally use a pass-through session to submit queries, DML statements, and DDL statements directly to data sources. In a pass-through session, you use the SQL dialect of the data source, rather than the SQL dialect of DB2.

Optional tasks are often performed by the Database Administrators and Application Programmers:

  • Modifying the mapping between a DB2 data type and a data source data type to override the default data type mapping

  • Modifying the mapping between a DB2 function and a data source function to override the default function mapping

  • Providing the federated server with the index specification information if a data source table has an index that the federated server is unaware of

After a federated system is set up, the information in data sources can be accessed as though it is in one large database. Users and applications send queries to one federated database, which retrieves data from multiple data sources. Applications work with the federated database just like with any other DB2 database.