# Lesson Notes By Weeks and Term - Senior Secondary 3

Dense and sparse index

Term: 1st Term

Week: 4

Class: Senior Secondary School 3

Age: 17 years

Duration: 40 minutes of 2 periods each

Date:

Subject:      Data Processing

Topic:-       Dense and sparse index

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Define dense and sparse index
2. Distinguish between dense and sparse index

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, pictures, Data Processing for senior Secondary Education by Hiit Plc, WAPB Computer Studies for Senior Secondary I by Adekunle et al, On-line Materials.

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

 PRESENTATION TEACHER’S ACTIVITY STUDENT’S ACTIVITY STEP 1 INTRODUCTION The teacher reviews the previous lesson on the clustered and unclustered indexes Students pay attention STEP 2 EXPLANATION He defines dense and sparse index Students pay attention and participates STEP 3 DEMONSTRATION He distinguishes between dense and sparse index Students pay attention and participate STEP 4 NOTE TAKING The teacher writes a summarized note on the board The students copy the note in their books

NOTE

DENSE VERSUS SPARSE INDEXES

DENSE INDEX

This is said to be dense if it contains (at least) one data entry for every search key value that appears in a record in the indexed file.

In a dense index, index record appears for every search key value in the file or table. That is every search key in the index column has a particular record it will point to in the table or file.

A Sparse Index contains one entry for each page of records in the data file. The index record contains the search key and a pointer to the first data record with that search key value. A Sparse index must be clustered and it is smaller than a dense index.

EVALUATION:    1. Distinguish between dense index and sparse index

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively