Database-MySQL [3i Infotech Placement]: Sample Questions 67 - 68 of 162

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Question 67

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Describe in Detail

Essay▾

What is ROWID?

Explanation

  • Every record has a unique ROWID within a database reprinting the physical location on disk where the record lives.
  • The ROWID is a unique database-wide physical address for every row on every table.
  • Once assigned (when the row is first inserted into the database) , it never changes until the row is deleted or the table is dropped.
  • The ROWID consists of the following three components, the combination of uniquely identifies the physical storage location of the row.
  • ROWID is automatically generated unique id of a row and it is generated at the time of insertion of row.
  • The ROWID is used internally in indexes as a quick means of retrieving rows with a particular key value.
  • Application developers also use it in SQL statements as a quick way to access a row once they know the ROWID

Example of ROWID

SELECT ROWID, last_name

FROM employees

WHERE department_id = 20;

Question 68

Question

MCQ▾

Which of the following is not an reason for the fact that most of the processing is done at the server?

Choices

Choice (4)

a.

To implement business rules centrally

b.

For application sharing

c.

To reduce network traffic

d.

None of the above

Answer

d.

Explanation

  • Server processes to handle the requests of client process connected to the instance.
  • A client process always communicates with a database through a separate server process.

Benefit of processing done at the server include:

  • Speed:
    • User can quickly access single page then download documents resulting in faster times.
  • Security:
    • Documents remain secure when using a server/client solution.
  • Maintenance:
    • Administrators no longer need to install user՚s versions of software or update multiple applications on every client.
  • Scalability:
    • Implementation is quicker and costs are lower.
  • Portability:
    • Users on any hardware or software platform that includes Java support, it have access to the same application and information wherever they are located.
  • Reducing network traffic, application sharing and implementing business rules centrally are all three reasons for most of the processing being done at the server.
  • Server processes to handle the requests of client process connected to the instance.
  • A client process always communicates with a database through a separate server process.

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