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:
Determines and designates a server as a DB2 federated server
Installs and configures the data source client software and links DB2 to the client software
Installs DB2 and creates the DB2 instance
Installs DB2 Relational Connect (if necessary)
Creates a wrapper for each category of data source that is to be included in the federated system
Supplies the federated server with a server definition for each data source and might supply server options to assist in optimizing distributed requests
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
Creates nicknames for the data source objects that are to be accessed
Application Programmers/End Users:
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.