JDBC Project - Emerald City Team

JDBC Exam Questions

1. How can I use JDBC to access a desktop database like Microsoft Access over a network?  ANSWER: Most desktop databases uses ODBC. The best approach is to use a commercial JDBC driver such as the drivers from Symantec and IDS software. The JDBC-ODBC bridge from JavaSoft does not provide network access to desktop databases by itself. The JDBC-ODBC bridge loads ODBC as a local DLL, and typical ODBC drivers for desktop databases like Access aren't networked. The JDBC-ODBC bridge can be used together with the RMI-JDBC bridge to access Access over the net. The solution from Dyade is free. Read more in the JDBC FAQ
   
2. Describe the four types of JDBC Drivers. ANSWER:
   • The JDBC-ODBC bridge uses ODBC drivers to access the database. When using the bridge, some ODBC binary code must exist on the client.
   • A native-API partly-Java driver converts JDBC calls into native API calls to access database.  This type of driver also requires that some binary code exists on the client.
   • A net-protocol all-Java driver translates JDBC calls into a vendor specific protocol which is then translated to a DBMS protocol by a server. According to Sun's website, this is the most flexible JDBC alternative. The examples in this website use this type of driver.
   • A native-protocol all-Java driver converts JDBC calls directly into the network protcol used by the DBMS.
   More specific information can be found on Sun's JDBC Site.
3. What is ODBC?  ANSWER: Open DataBase Connectivity (ODBC) is an Application Programming Interface (API) that allows a programmer to abstract a program from a database. When writing code to interact with a database, you usually have to add code that talks to a particular database using a proprietary language. If you want your program to talk to an Access, Fox and Oracle databases you have to code your program with three different database languages. This can be quite the daunting task causing much grief. Now, enter ODBC... When programming to interact with ODBC you only need to talk the ODBC language (a combination of ODBC API function calls and the SQL language). The ODBC Manager will figure out how to contend with the type of database you are targeting. Regardless of the database type you are using, all of your calls will be to the ODBC API. All that you need to do is have installed an ODBC driver that is specific to the type of database you will be using.
4. Are JDBC Java applications truly portable? ANSWER: No, it depends on what database you are connecting to and on which platform. For the most part, if you are working on the Microsoft Windows platform, you can use the JDBC-ODBC bridge designed by Sun Microsystems to connect to any database in Windows that is ODBC compatible. However, if you are using a UNIX or Linux platform, you will need the JDBC drivers from the vendor of the database you are using. Therefore, depending on the platform and database you are developing your Java application for, the code may not be truly portable.
5. What advantage is there to writing JDBC applications? ANSWER: By writing applications to the JDBC specifications, application developers can spend less time porting their code to specific operating systems and DBMS's, and more time improving their client applications and responding to users' needs. Furthermore, information technology units can distribute one client application to its users instead of several, each for a certain data source. Finally, Java applets can be developed on the World Wide Web to allow customer interaction with corporate databases via that customer's favorite Web browser.