|A DB2 federated system is a special type of distributed database management |system (DBMS). A federated system allows you to query and retrieve data |located on other DBMSs. A single SQL statement can refer to multiple |DBMSs or individual databases. For example, you can join data located |in a DB2 Universal Database table, an Oracle table, and a Sybase view.
|A DB2 federated system consists of a server with a DB2 instance, a database |that will serve as the federated database, and one or more data |sources. The federated database contains catalog entries identifying |data sources and their characteristics. A data source |consists of a DBMS and data. Supported data sources include: |
|DB2 Universal Database federated servers communicate with and retrieve data |from data sources using protocols, called wrappers. The |wrapper that you use depends on the operating system on which the DB2 instance |is running. Nicknames are used to identify the tables and |views located at the data sources. Applications can connect to the |federated database just like any other DB2 database, and query the data |sources using nicknames as if they were tables or views in the federated |database.
|After a federated system is set up, the information in the data sources can |be accessed as though the data is in a single local database. Users and |applications send queries to the federated database, which retrieves data from |the data sources.
|A DB2 federated system operates under some restrictions. Distributed |requests are limited to read-only operations in DB2 Version 7. In |addition, you cannot execute utility operations (LOAD, REORG, REORGCHK, |IMPORT, RUNSTATS, and so on) against nicknames. You can, however, use a |pass-through facility to submit DDL and DML statements directly to DBMSs using |the SQL dialect associated with that data source.
|To successfully create nicknames for DB2 for UNIX and Windows Version 8 |tables and views, you must apply the DB2 for UNIX and Windows Version |7.2 Fixpak 8 to your DB2 for UNIX and Windows Version 7.2 |federated database. If you do not apply Fixpak 8 to your DB2 for UNIX |and Windows Version 7.2 federated database, an error will occur when |you access the nicknames.
|The new wrappers in Version 7.2 (such as Informix on AIX, HP, and |Solaris Operating Environment; Oracle on Linux, HP, and Solaris Operating |Environment; Sybase on AIX and Solaris Operating Environment; and |Microsoft SQL Server on AIX and NT) are not available in this FixPak ; |you must purchase DB2 Relational Connect Version 7.2.
|This section provides instructions for installing DB2 Relational Connect on |the server that you will use as your federated system server. |Relational Connect is required to access Oracle, Sybase, Microsoft SQL Server, |and Informix data sources. DB2 Relational Connect is not required to |access members of the DB2 Universal Database family.
|Before Installing DB2 Relational Connect: |
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|x:\setup /i language
|where: |
|The installation launchpad opens.
|When the installation is complete, DB2 Relational Connect will be installed |in the directory along with you other DB2 products. For example, the |wrapper library for the Oracle NET8 client software (net8.dll) will be |installed in the c:\Program Files\SQLLIB\bin directory. |
|To install DB2 Relational Connect on your UNIX federated server, use the |db2setup utility.
|Note: The screens that appear when you use the |db2setup utility depend on what you already have installed on the federated |server. These steps assume that you do not have Relational Connect |installed. |
|When the installation is complete, DB2 Relational Connect will be installed |in the directory along with your other DB2 products. |
|The nickname parameter in a CREATE NICKNAME statement is a two-part |name--the schema and the nickname. If you omit the schema when |creating the nickname, the schema of the nickname will be the authid of the |user creating the nickname. After a nickname is created, information |about the nickname is stored in the catlaog views SYSCAT.TABLES, |SYSCAT.TABOPTIONS, SYSCAT.COLUMNS, SYSCAT.COLOPTIONS, and |SYSCAT.INDEXES.
|When you restore a federated database backup onto a different federated |server, the database image does not contain the new database and node |directory information it needs to access the DB2 family data sources. |You must catalogue this information when you perform the restore.