Database [3i Infotech Placement]: Sample Questions 187 - 188 of 294

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Question 187

Database
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Describe in Detail

Essay▾

What is DML (Data Manipulation Language) ?

Explanation

Define Data Defination Language
  • Data Manipulation is:
    • retrieval of information from the database
    • insertion of new information into the database
    • deletion of information in the database
    • modification of information in the database
  • A DML is a language which enables users to access and manipulate data.
  • The goal is to provide efficient human interaction with the system.
  • There are two types of DML:
    • procedural: the user specifies what data is needed and how to get it
    • nonprocedural: the user only specifies what data is needed
      • Easier for user
      • May not generate code as efficient as that produced by procedural languages
  • A query language is a portion of a DML involving information retrieval only. The terms DML and query language are often used synonymously.

Question 188

Database

Question

MCQ▾

What are the SQL clauses supported in the link property sheet?

Choices

Choice (4)

a.

WHERE & START WITH

b.

START WITH & HAVING

c.

WHERE, START WITH & HAVING

d.

WHERE & HAVING

Answer

c.

Explanation

  • WHERE, START WITH & HAVING are the SQL clauses supported in the link property sheet.

WHERE Cause

  • Used to filter the result from a SELECT, INSERT, UPDATE, or DELETE statement.

    Syntax

    WHERE conditions;

START with Cause

  • Appears in hierarchical SQL queries and queries data with master details relationships.
  • Marks node starting node or level of the tree structured data.
  • Scalar value can be assigned the root of the query.

Syntax

SELECT [COLUMNS]

FROM TABLE_NAME

START WITH [COLUMN] = [ROOT NODE VALUE]

CONNECT BY [CONDITION]

HAVING Clause

  • Restricts the results of a GROUP BY in a selectExpression.
  • Applied to the entire result as a single group.

Syntax

HAVING searchCondition

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