Introduction to indexing and methods of indexing: Indexing serves as a fundamental organizational tool that facilitates easy access to information by systematically cataloging and structuring content, enabling efficient retrieval and navigation within diverse sources of data and documents.

1. Dr. SK Illangarathne
Senior Assistant Librarian
Technology Library
Faculty of Technology
Rajarata University of Sri Lanka
skillangarathne@gmail.com

2. 1. File Indexing
File indexing is a technique used to optimize the retrieval of records or
specific data from a file. It involves creating an index, which is a data
structure that maps key values to their corresponding data locations
within the file. File indexing facilitates quick and efficient search
operations by reducing the time complexity of data retrieval.

3. 2. Methods of Indexing (Hard-Files)
When managing office records and files in a manual, paper-based
environment, indexing methods play a crucial role in organizing and
retrieving information efficiently. Here are some common indexing
methods used in offices with printed records and files:
1.Alphabetical Indexing: Organizing files alphabetically based on names,
subjects, or categories simplifies retrieval. Using alphabetical dividers or tabs
within filing cabinets helps in locating specific documents quickly.
2.Numerical Indexing: Assigning unique numbers to files or documents and
maintaining a corresponding numerical index can aid in systematic organization
and retrieval of records.
3.Chronological Indexing: Sorting files based on dates or timestamps helps track
the sequence of events and monitor the timeline of activities. Using date stamps or
labels can facilitate chronological indexing.
4.Subject Indexing: Categorizing files by subjects or topics and creating a subject
index listing the content of each file enables users to locate information based on
the subject matter.

4. 2. Methods of Indexing (Hard-Files)
Color-Coding: Assigning specific colors to different categories or types of
files can visually differentiate and group documents, enhancing the speed
and accuracy of file retrieval.
Cross-Referencing: Creating cross-references between related files or
documents can link relevant information together, facilitating
comprehensive access to interconnected data.
Keyword Indexing: Highlighting keywords or key terms on file labels or
index cards can assist users in quickly identifying relevant documents
based on specific keywords.
Geographical Indexing: For offices dealing with location-specific records,
organizing files by geographical regions or areas can streamline access to
information based on physical locations.

5. 2. Methods of Indexing
a. Sequential Indexing:
Definition: Sequential indexing involves arranging data records in a
sequential order based on a specific key field. This key field serves as a
reference point for locating records within the file.
b. Hash Indexing:
Definition: Hash indexing uses a hash function to map key values to
their corresponding data locations in the file. This method offers fast
retrieval times by directly calculating the storage location of the data
based on the hash value.
c. Clustered Indexing:
Definition: Clustered indexing organizes data records based on their
key values. It physically groups together the records with similar key
values, allowing for efficient retrieval of data based on range queries or
specific key values.

6. 2. Methods of Indexing
a. Sequential Indexing:
Definition: Sequential indexing involves arranging data records in a
sequential order based on a specific key field. This key field serves as a
reference point for locating records within the file.
b. Hash Indexing:
Definition: Hash indexing uses a hash function to map key values to
their corresponding data locations in the file. This method offers fast
retrieval times by directly calculating the storage location of the data
based on the hash value.
c. Clustered Indexing:
Definition: Clustered indexing organizes data records based on their
key values. It physically groups together the records with similar key
values, allowing for efficient retrieval of data based on range queries or
specific key values.

7. 2. Methods of Indexing
d. Dense Indexing:
Definition: Dense indexing creates an index entry for every data record
in the file. This method facilitates direct access to individual records by
using the index entries as pointers to their physical locations.
e. Sparse Indexing:
Definition: Sparse indexing creates index entries only for a subset of
data records in the file. This reduces the size of the index and improves
search efficiency for specific key values.