Understanding DB2: Learning Visually with Examples (2nd Edition)

1.12. Case Study

John recently graduated from Pennsylvania State University, where he learned DB2 UDB as part of the IBM Scholars' program, a program that provides DB2 UDB for free to teach database skills.

While at school, he worked with the DB2 UDB Enterprise Server Edition installed in a pSeries machine at the university computer lab. He was given SYSADM authority, and he was able to see connections from many different clients to all created databases using the list applications command. John wanted to develop a Java application using the JDBC type 2 application driver, so he downloaded and installed the six-month Try and Buy version of DB2 UDB Personal Edition. After he installed this edition, he realized that only the Administration client was included, but that he needed the application development (AD) client for some library and header files to develop the program. Fortunately, all DB2 UDB clients are free of charge, so he downloaded the AD client from the IBM DB2 support Web site (see the Resources section at the end of this book), and he was then able to build, test, and run his application against the DB2 UDB Personal Edition on his laptop. Since the client and database server were both on his laptop, he was dealing with a local client connection.

John wanted to test whether his application would work as a remote client, so he used the client software that comes with DB2 UDB Personal Edition to test his application against the database he had created earlier on the university's pSeries computer. This also worked, and John was feeling like a DB2 guru.

Eager to show his program to his colleagues, he emailed the executable to his friend Peter, who had just bought a new laptop with Microsoft Windows XP Professional Edition installed. Peter detached the file and tried to run the application against John's database on the University's pSeries server. After spending a few hours trying to figure out why he couldn't, he dropped by John's place. John realized that Peter had to install a DB2 client, as this is a requirement for JDBC type 2 programs. Given that Peter was neither going to develop a new program nor administer a database, John asked Peter to download the runtime client from the IBM Web site. He also asked him to issue a few commands to set up the connectivity between the client and the server . . . and voila, the program successfully ran. Peter then asked John to perform the test from his laptop against the database on John's laptop, but John said it would not work because he had installed DB2 UDB Personal Edition, which is not a database server, and it cannot accept inbound remote client connections.

After the graduation ceremony, John received a PDA as a gift from his dad. His dad had heard John praise DB2, so he had had DB2 Everyplace installed on the PDA. Since John was going to take six months off to travel before looking for a job, John decided to take his PDA with him rather than his laptop. John's account at the university was going to be active for the next nine months, so while he was traveling he could connect to his "old" database on the pSeries and use his application (which he had installed on his PDA) to transfer information about all the friends he met and places he visited during his trip. This way he was able to save information in another place should he lose his PDA.

After his trip, John applied for a position at a medium-sized company in his hometown. To prepare for his interview, John again tested the program he had written against his laptop database, but the Try and Buy evaluation period had expired. John figured that he would always need DB2 UDB on his laptop, so he decided to buy the permanent license. When John received the license file after the purchase, he installed it on his laptop with the command db2licm -a filename. Once this problem was resolved, John showed his program during the job interview and was immediately hired.

Company ABC, which was using DB2 UDB Workgroup Server Edition, asked John to modify his application so that it would connect to a DB2 UDB for z/OS host machine. John responded that he did not need to make any modifications, but since DB2 UDB Workgroup Server Edition does not come with the DB2 Connect software component, either the company needed to purchase this software, or obtain the DB2 UDB Enterprise Server Edition. Given that the ABC company was a software development company, John suggested purchasing the DB2 Universal Developer's Edition (UDE), as it would be cheaper and has all of the software for all DB2 UDB editions. If ABC company wanted to use DB2 in a production environment, they would not be able to use DB2 UDE, but would have to buy the appropriate license.

Company ABC was also interested in the DB2 UDB Express Edition, because one of their applications needs a database to be embedded as part of their solution. Other than John, there are not many skilled DB2 personnel in the company, so DB2 UDB Express is also ideal because of its ease-of-use features.

Three months after John was hired, he was promoted. John is well on his way to a very successful career with DB2 UDB!