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Question number: 537

» Database » MySQL

Essay Question▾

Describe in Detail

What is Buffer Manager?

Explanation

Given buffer management.

Given Buffer Management.

Given buffer management.

  • Responsible primarily for managing the operations inherent saving and loading of the blocks.

  • Reads disk pages into a main memory page as needed.

  • Used by access methods, heap files, and relational operators to read/write page.

  • Makes calls to the underlying DB class object, which actually performs these functions on disk pages.

  • Must use some techniques in order to provide good service:

    • Replacement Strategy

    • Pinned Blocks

    • Forced Output of Blocks

Question number: 538

» Database » MySQL

MCQ▾

Question

PL/SQL supports datatype.

Choices

Choice (4) Response

a.

Scalar datatype

b.

Composite datatype

c.

Both a. and b. are correct

d.

Question does not provide sufficient data or is vague

Answer

c.

Explanation

PL/SQL Datatypes in image

PL/SQL Datatypes in Image

PL/SQL Datatypes in image

Data types:

  • Scalar type

    • Has no internal components.

    • Reference single value

  • Composite type

    • Has internal components it can be manipulated individually.

    • Use PL/SQL records when we want to store value of different data types.

    • Use when we want to store value of the same data type.

  • Reference type

    • Holds values, called pointers and that designate other program item.

  • LOB type

    • Hold value, called lob locators, that specify the location of large object that store out-of-line.

Image show the Data types

Image Show the Data Types

Image show the Data types

Predefine data types and sub data types:

Table of the data types and sub data types

Table of the data types and sub data types

Category

Data Description

Numeric

Can perform arithmetic operation

character

Alphanumeric value respects single character or string

BOOLEAN

Logical value- can perform logical operations.

Datetime

Dates and times.

Interval

Time intervals.