3i Infotech Placement: Sample Questions 322 - 324 of 1245

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Question 322

Describe in Detail Essay▾

What is 4NF?

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Explanation

Forth Normal Form (4NF)
  • Tables cannot have multi-valued dependencies on a Primary Key.
  • A relation schema R is said to be in 4NF if for every Multivalued dependency X Y that holds over R, one of following is true
  • X is subset or equal to (or) XY = R.
  • X is a super key.

Question 323

Describe in Detail Essay▾

What is statement in java?

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Explanation

  • “Statement” provides methods to execute queries on the the database.
  • Statement interface is a factory of ResultSet.
  • Provides factory method to get the object of ResultSet.

Methods of Statement interface:

  1. Public ResultSet executeQuery
    • Used to execute SELECT query.
    • Return the object of ResultSet
    • Public int executeUpdate
    • Used to excute specified query.
    • It create, drop, insert, update, delete.

      Used to execute batch of commands.

  2. Public boolean execute
    • Used to execute queries that may return multiple results.
    • Public int [] executeBatch
Methods of Statement Interface

Question 324

Question MCQ▾

A postal truck leaves its station and heads for Chicago, averaging 40mph. An error in the mailing schedule is spotted and 24 minutes after the truck leaves, a car is sent to overtake the truck. If the car averages 50mph then how long will it take to catch the postal truck?

Choices

Choice (4)

a.

1.5 hours

b.

1.6 hours

c.

2 hours

d.

3 hours

Edit

Answer

c.

Explanation

A postal truck leaves the station and heads for Chicago, averaging 40 mph.

An error in the mailing schedule is spotted and 24 minutes after the truck leaves, a car is sent to overtake the truck. The speed of car is 50mph.

Distance covered by both truck and car is same.

Let time taken by truck is x minutes and car is taking minutes.

So, Car will take 2 hours time to catch the postal truck.