Database-MySQL [3i Infotech Placement]: Sample Questions 26 - 28 of 162

Glide to success with Doorsteptutor material for competitive exams : get questions, notes, tests, video lectures and more- for all subjects of your exam.

Question 26

Edit

Write in Short

Short Answer▾

Which command executes the contents of a specified file?

Explanation

  • START or@command executes the contents of a specified file.
  • Script can only called from a url.

Question 27

Edit

Describe in Detail

Essay▾

What is “transparent DBMS”

Explanation

  • It is one, which keeps its Physical Structure hidden from user.
  • A query with respect to DBMS relates to user commands that are used to interact with a database.
  • The query language can be classified into data definition language and data manipulation language.
  • Transparent hides implementation details from the user.
  • For example in a centralized DBMS, data independence is a form of transparency it hides changes in the definition and organization of the data from the user.
  • A DDBMS may provide a various· levels of transparency.
  • They all participate in the same overall objective: to make the use of the distributed database, equivalent to that of a centralized database.

Four types of transparency in DDBMS:

  • Distribution transparency
  • Transaction transparency
  • Performance transparency;
  • DBMS transparency.

Question 28

Edit

Write in Short

Short Answer▾

What is 3NF?

Explanation

  • A relation schema R is in 3NF if it is in 2NF and every FD X A either of the following is true
  • X is a Super-key of R
  • A is a prime attribute of R
  • In other words, if every non prime attribute is non-transitively dependency on primary key.

Developed by: