Answer:
b. data entry slows as every INSERT , UPDATE, or DELETE statement must also update every index.
Explanation:
This process help to improve the speed of get data , it takes each element in the indexed column and save the location to get faster the data. But if you index every attribute in a table it going to take a lot of time locating each column in the respective index in each query(update, delete and insert). For that reason is necesary be carefull with this process and only put index in the relevant columns
What are the options and if it's meaning like when you save something it has .pdf .jpg or .doc after the title then it would be ".doc"
Answer:
2. <em>A reference of type A can be treated as a reference of type B</em> - False
Base class or its objects are not related to their derived class (or its objects).
Explanation:
class A {
int a;
public A() {
a = 7;
}
}
class B extends A {
int b;
public B() {
b = 8;
}
}
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1. <em>After the constructor for class B executes, the variable a will have the value 7 </em>- True.
When an object of a derived class is declared, the constructor of base class is called before the constructor of derived class (is called).
3. <em>Both variables a and b are instance variables </em>- True.
Classes can have instance, or member, variables and methods.
4.<em> After the constructor for class B executes, the variable b will have the value 8</em> - True.
When object of class B is declared, its constructor was called, which initialized variable b to 8.