10 Apr, 2007
Database Interview Questions
- How does one deploy SQLJ programs? Use the sqlj compiler to compile your *.sqlj files to *.java and *.ser files. The *.ser files contain vendor specific database code. Thereafter one invokes the javac compiler to compile the .java files to *.class files. The *.class and *.ser files needs to be deployed.
- What is JDeveloper and what is it used for? JDeveloper is the Oracle IDE (Integrated Development Environment) for developing SQLJ and JDBC programs, applets, stored procedures, EJB’s, JSP’s etc.
- What is InfoBus DAC and what is it used for? InfoBus DAC (Data Aware Controls) is a standard Java extension used in JDeveloper to create data aware forms. It replaced the JBCL interface that were used in JDeveloper V1 and V2.
- What is a JSP and what is it used for? Java Server Pages (JSP) is a platform independent presentation layer technology that comes with SUN’s J2EE platform. JSPs are normal HTML pages with Java code pieces embedded in them. JSP pages are saved to *.jsp files. A JSP compiler is used in the background to generate a Servlet from the JSP page.
- What is the difference between ASP and JSP? Active Server Pages (ASP) is a Microsoft standard, which is easier to develop than Java Server Pages (JSP). However ASP is a proprietary technology and is less flexible than JSP. For more information about ASP, see the Oracle ASP FAQ.
- How does one invoke a JSP? A JSP gets invoked when you call a *.jsp file from your Web Server like you would call a normal *.html file. Obviously your web server need to support JSP pages and must be configured properly to handle them.
- How does a JSP gets executed? The first time you call a JSP, a servlet (*.java) will be created and compiled to a .class file. The class file is then executed on the server. Output produced by the servlet is returned to the web browser. Output will typically be HTML or XML code.
- What is a Java Stored Procedure/ Trigger? A Java Stored Procedure is a procedure coded in Java (as opposed to PL/SQL) and stored in the Oracle database. Java Stored procedures are executed by the database JVM in database memory space. Java Stored Procedures can be developed in JDBC or SQLJ. Interfacing between PL/SQL and Java are extremely easy. Please note that Java Stored procedures are by default executed with invokers rights. PL/SQL procedures are by default executed with defines rights.
