3i Infotech Placement: Sample Questions 371 - 372 of 1245

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Question 371

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Short Answer▾

What is cladding?

Explanation

  • The plastic or glass sheath that is fused to and surrounds the core of an optical fiber.
  • It is a layer of a glass surrounding the centre fiber of glass inside a fiber-optic cable.
  • The cladding is covered with a protective outer jacket - placed on the exterior of wood frame and sash components providing ease of maintenance.
  • Common cladding materials include vinyl and extruded or roll-formed aluminium.

Question 372

Question

MCQ▾

In mapping of ERD to DFD

Choices

Choice (4)

a.

Relations in ERD has 1 to 1 correspondence to processes in DFD

b.

Entities in ERD should correspond to an existing entity/store in DFD

c.

Relationships in ERD has 1 to 1 correspondence to flows in DFD

d.

Entity in DFD is converted to attributes of an entity in ERD

Answer

b.

Explanation

  • DFD- Data Flow Diagram- shows how data enters a system, are transformed in that system, and how it is stored in it.
  • ERD - Entity Representation Diagram- represents the entity model and will show what a system or a database will look like but not explain how to implement it.
  • Entities in ERD should correspond to an existing entity/store in DFD.

ERD

  • ERD is a snapshot of data structures.
  • Shows entities (tables) in a database and relationships between tables within that database.
  • For a good database design it is essential to have an ERD.

DFD

  • DFD is a graphical representation of the “flow” of data through an information system.
  • It views a system as a function that transforms the input into desired output.

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