FAQ SQL and PLSQL

3: -What is the difference between an Applet and a Servlet?
A3: -Applets are Java programs that are parts of Web pages. They are downloaded through the listener to a compliant Web browser and are executed on the client machine. Servlets are host-based Java programs that build dynamic Web pages that are then passed back to the Web browser

5: -What is a virtual address?
A5: -What follows the first / of a URL is the virtual address, which relates to a physical location on the particular computer

6: -Briefly describe why one might use PL/SQL or Java or Portal (and vice versa).
A6: -Programmers are already familiar with PL/SQL but features might be limited, Java has a steep learning curve, Portals appearance is not that flexible.

3: -Why would you want to call another PL/SQL procedure in a Web environment?
A3: -This called pl/sql is a way of giving a consistent look with appearances and error messages across the Web site



1.What is a PL/SQL Page?
A1: -PL/SQL Pages are a way of imbedding PL/SQL into existing HTML Web applications

2: -Why would you want to use PL/SQL procedures in a JSP?
A2: -PL/SQL is excellent for Oracle database interaction

3: -What are Apache Virtual Directories useful for?
A3: -They are aliases and will allow for more Web-environment-neutral access to files (such as pictures, code, and so on)


1: -What would be the advantage of a partitioned index?
A1: -To make less b*tree levels when indexing very large tables

2: -What is the advantage of an IOT over that of a HEAP Table?
A2: -No underlying table structure is required

3: -Why does IOTs have the pseudo column 'ROWID'?
A3: -So that indexes can be created on IOTs

4: -What is a b*tree level telling you?
A4: -The number of levels in the index, the fewest number of reads required to find a table ROWID

5: -Show the syntax to make a SQL statement use an existing index when a calculation on the indexed column is desired.
A5: -WHERE sal > 1000/1.10

6: -List some of the benefits and penalties of using bitmapped indexes.
A6: -Advantages: Speed Disadvantages: Causes exclusive lock on table during DML, very slow at DML.

7: -What is clustering factor?
A7: -Clustering factor is a relationship between the number of data blocks being referenced by each index leaf block