Technology Questions

Cursors help you manipulate the information retrieved by select statements. This can be done by assigning a name to the cursor.

Example:

CURSOR emp_cur 

IS 

SELECT emp_number from employee_tbl where employee_name = name_in;

Types of Cursors:

Implicit cursors- These cursors are not declared by the programmer. They are issued when the SQL statement is executed. The open, close and fetching is done by itself.

Example:

UPDATE employee SET salary = salary * 2.1;

Here, an implicit cursor is issued to identify the set of rows in the table which would be affected by the update.

Explicit cursors- These cursors are defined by programmer. They are used in queries that return multiple rows.

Example:

CURSOR emp_cur 

IS 

SELECT emp_number from employee_tbl where employee_name = name_in;

Autoboxing is the process of converting a primitive type data into its corresponding wrapper class object instance.

Example:

Integer number = new Integer (100); // number is now refers to the object 100

Unboxing is the process of converting a wrapper instance into a primitive type.

Example: 

Integer number = new Integer (100); 

int num = number;// without type casting number would be changed into int type

A table of data representing a database result set, which is usually generated by executing a statement that queries the database.

ResultSet object maintains a cursor pointing to its current row of data. Initially the cursor is positioned before the first row. The next method moves the cursor to the next row, and because it returns false when there are no more rows in the ResultSet object, it can be used in a while loop to iterate through the result set.

Oracle NOT NULL is used on a column to ensure that the value for that column can never be NULL.
Example:
Below, the constraint is that the id should never be NULL. If it is, oracle throws an error.
create table employee ( id number NOT NULL, Name varchar(200) );

Interface data is static data why bcoz interface supports multiple inheritance.

if inteface data is non-static then there is chance for replication of the data (bcoz of replication of data ambiguity problem occurs )

The JVM performs three main tasks:

• Loads code

• Verifies code

• Executes code

-To store information usually relevant to browsers and search engines.

-To only store information usually relevant to browsers

-To only store information about search engines.

-To store information about external links

CDATA - (Unparsed) Character Data

The term CDATA is used when you dont want some text data to be parsed by the XML parser.

A CDATA section starts with "<![CDATA[" and ends with "]]>":