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Question 1: What is the three tier
model?
Answer: It is the presentation,
logic, backend
Question 2: Why do we have index
table in the database?
Answer: Because the index table
contain the information of the other
tables. It will
be faster if we access the index table
to find out what the other contain.
Question 3: Give an example of using
JDBC access the database.
Answer:
try
{
Class.forName("register the driver");
Connection con =
DriverManager.getConnection("url of db",
"username","password");
Statement state = con.createStatement();
state.executeUpdate("create table
testing(firstname varchar(20), lastname
varchar(20))");
state.executeQuery("insert into testing
values(’phu’,'huynh’)");
state.close();
con.close();
}
catch(Exception e)
{
System.out.println(e);
}
Question 4: What is the different of
an Applet and a Java Application
Answer: The applet doesn’t have the
main function
Question 5: How do we pass a
reference parameter to a function in
Java?
Answer: Even though Java doesn’t
accept reference parameter, but we can
pass in the object for the parameter of
the function.
For example in C++, we can do this:
void changeValue(int& a)
{
a++;
}
void main()
{
int b=2;
changeValue(b);
}
however in Java, we cannot do the same
thing. So we can pass the
the int value into Integer object, and
we pass this object into the
the function. And this function will
change the object. |