9. Using DB2 UDB

This section gives you the basic information you need to start working with DB2 UDB on Linux. It includes instructions on issuing DB2 UDB commands and SQL statements from the command line, as well as the commands you need to start the DB2 UDB Control Center and the DB2 UDB Information Center.

9.1. DB2 UDB Control Center

The left side of the DB2 UDB Control Center provides an object-oriented view of the database objects that you have catalogued, including DB2 UDB instances and databases on other DB2 UDB servers. One way to add, edit, or drop database objects is to right-click on an object to bring up a menu.

To start the DB2 UDB Control Center

  1. Ensure you are logged on to your Linux workstation using either the DB2 UDB Administration Server user ID or the DB2 UDB instance user ID. If you use the su command to become the user, ensure you include the -l parameter to initialize the environment for the user.

  2. Start the X server, if it is not already started.

  3. Issue the db2cc command to start the DB2 UDB Control Center.

9.2. DB2 UDB Information Center

As mentioned above, the new DB2 UDB Information Center is a revamped documentation display system that now encapsulates the task, concept and reference information required to properly run DB2 UDB. It can be installed locally, on an intranet server, or accessed directly from an ibm.com hosting service

To start the DB2 UDB Information Center:

  1. Ensure you are logged on to your Linux workstation using either the DB2 UDB Administration Server user ID or the DB2 UDB instance user ID. If you use the su command to become the user, ensure you include the -l parameter to initialize the environment for the user.

  2. Ensure that the X server is started, because the Information Center requires a Web browser.

  3. Issue one of these launch commands:

    • db2help

    • db2ic

    • db2cc -ic

Alternatively, you can launch the Information Center from within the Control Center (or any of the other GUI tools), by clicking an item under the "Help" menu, or by clicking on the "?" icon.

If you did not install the DB2 UDB Information Center, or have not configured your tools to use a different server, these commands will launch a detected browser, and take you directly to the IBM hosted DB2 UDB Information Center at http://publib.boulder.ibm.com/infocenter/db2help/.

9.3. DB2 UDB CLP

If you are logged on to your Linux workstation using either the DB2 UDB Administration Server user ID or the DB2 UDB instance user ID, you can issue DB2 UDB commands and SQL statements from the command line.

If this is your first time using DB2 UDB, I would suggest creating the sample database that ships with DB2 UDB. The sample database is used throughout the DB2 UDB documentation and is required by most of the sample applications.

To create the sample database, you can either select the Create the sample database option from the DB2 UDB First Steps launchpad, or by issuing the db2sampl command.

Before you can issue an SQL statement, you have to connect to a database. To connect to a database, enter the command:
db2 CONNECT TO database USER userID USING password

To connect to a database, and have DB2 UDB prompt you for the password, issue the command:
db2 CONNECT TO database USER userID

To connect to a database using the default user ID, issue the command:
db2 CONNECT TO database

Once you have connected to a database, you can then issue SQL statements or DB2 UDB commands against that database. For example, to select all of the columns from the EMPLOYEE table in the SAMPLE database, issue this command:
db2 "SELECT * FROM employee"

You can avoid typing db2 as the prefix for every SQL statement and DB2 UDB command by issuing DB2 UDB commands using the Command Line Processor (CLP). To start the CLP, issue the db2 command by itself. DB2 UDB provides the following prompt:
You can issue database manager commands and SQL statements from the
command prompt. For example:
    db2 => connect to sample
    db2 => bind sample.bnd

For general help, type: ?. 
For command help, type: ? command, where command can be 
the first few keywords of a database manager command. For example: 
 ? CATALOG DATABASE for help on the CATALOG DATABASE command
 ? CATALOG          for help on all of the CATALOG commands. 

To exit db2 interactive mode, type QUIT at the command prompt. Outside 
interactive mode, all commands must be prefixed with 'db2'. 
To list the current command option settings, type LIST COMMAND OPTIONS. 

For more detailed help, refer to the Online Reference Manual. 

db2 => 

Some users prefer to avoid the CLP because it prevents using the command line history features of the shell.

Some users claim that running the CLP within an Emacs shell gives them the best of both worlds: they get command line history, and they don't have to escape commands that contain lots of quotation marks and brackets.