DbSchema | How to Create Indexes in SQLite?

Sqlite • 06-Jun-2023

by Malik Umair Sajjad

SQLite alt >

Introduction
Prerequisites
What is an Index?
The Usage of Indexes
Advantages and Limitations of Using an Index
Types of Index
Creating an Index in sqlite3
Creating an Index in DbSchema
Conclusion
References

Introduction

In any relational database, managing and organizing data effectively is key to maintaining good performance. Indexes play an integral role in this aspect by improving data retrieval speed. This article will provide an in-depth understanding of how to create indexes in SQLite using sqlite3 and DbSchema.

Prerequisites

Basic understanding of SQL and relational databases
SQLite3 installed on your local system
DbSchema installed on your local system

For installation and establishing connection you can read our article SQLite-How to create a database?

What is an Index?

An index is a data structure that improves the speed of data retrieval operations on a database table. It works similarly to an index in a book, providing a quick way to access the content without going through each page. The index in databases does this by creating a data structure that can be quickly traversed to find the location of a data record.

Structure of Index alt >

The Usage of Indexes

Indexes are mainly used to speed up the retrieval of data from the database. They are exceptionally efficient in situations where there is a large amount of data, and you need to perform queries to retrieve data based on some conditions.

Advantages and Limitations of Using an Index

Advantages:

Improved Query Speed: Indexes significantly enhance the speed of data retrieval operations in a database.
Efficient Data Sorting: They aid in returning sorted data faster.
Rapid Record Management: Indexes enhance the speed of operations such as insert, update, and delete with WHERE clauses.

Limitations:

Space Requirement: Indexes require additional space on the disk.
Impact on Insertion, Deletion, and Update Operations: Since indexes require continuous maintenance, insert, update, and delete operations become slower.

Types of Index

*Index Type*	*Description*
Unique Index	This type of index ensures that all the values in the index are unique.
Composite Index	This is an index on two or more columns of a table.
Implicit Index	SQLite automatically creates an implicit index when we create a UNIQUE constraint or a PRIMARY KEY constraint.

Creating an Index in sqlite3

Step 1: Open SQLite3

Start by opening your SQLite3 console. You can do this by typing sqlite3 in your terminal or command prompt.

sqlite3

Step 2: Connect to Your Database

Connect to your database using the .open command followed by the database name. If the database doesn’t exist, SQLite3 will create it. Here is an example:

.open sampleDB.db

To know more about creating a database you can read our article SQLite-How to create a database?

Step 3: Create or Connect to Your Table

If you’re starting a new database, you’ll need to create a table. If you’re connecting to an existing database, you can skip this step.

Here is an example of how to create a table:

CREATE TABLE students(  
id INTEGER PRIMARY KEY,  
name TEXT NOT NULL,  
age INTEGER NOT NULL  
);

To know more about creating a table you can read our article SQLite-How to create a Table?

Step 4: Create a Non-Unique Index:

Now you can create a non-unique index using the CREATE INDEX SQL command. This will create an index on the name column:

CREATE INDEX idx_student_name ON Students (name);

Here, __idx_student_name` is the index name.

Step 5: Create a Unique Index:

If you wish to create a unique index that ensures all values in the index are unique, use the CREATE UNIQUE INDEX command:

CREATE UNIQUE INDEX idx_student_id ON Students (id);

Here, __idx_student_id` is the unique index name.

Step 6: Check Index:

Finally, you can check whether your index has been created correctly using the .indices command followed by the table name:

sqlite> .indices Students

Creating an Index in DbSchema

Step 1: Launch DbSchema

Start the DbSchema software. You will be greeted with the Connect to Database window.

Step 2:Create a New Connection

Click on the Create New Connection button. A new window will pop up.

Step 3:Set Connection Details

In this new window, choose the DBMS as SQLite, provide the necessary information such as the database file (or choose to create a new one), and click on the Test Connection button to ensure the settings are correct. Once verified, click on the Connect button.

Step 4:Select Table

In the main DbSchema window, you will see your database’s schema. Right-click on the table where you want to create an index, and select Open in Diagram. This will open a new window with the table schema.

Step 5:Navigate to the Indexes Tab

In this window, you’ll see a tab named Indexes / Foreign Keys. Click on this tab to see the current indexes and create new ones.

Step 6:Create a New Index

Click on the New Index button, and a new window will pop up. In this window, provide the index name, select the index type (Unique or Not Unique), and add the required columns to the index.

Step 7:Save the Index

Once you have provided the necessary information, click on the Save button. This will create the index, and you will see it in the Indexes / Foreign Keys tab.

Step 8:Apply Changes

To make sure the changes are applied to the actual database, go to the main DbSchema window and click on the Refresh button.

Visually Manage SQLite using DbSchema

DbSchema is a SQLite client and visual designer. DbSchema has a free Community Edition, which can be downloaded here.

Key Features of DbSchema:

Following are the key features of DbSchema which distinguish it from other database GUI tools.

Conclusion

Indexes play an integral role in enhancing the speed of data retrieval in databases. This article provided an in-depth understanding of what indexes are, their types, and how to create them in SQLite using sqlite3 and DbSchema. Despite the benefits, remember that indexes come with their limitations. Careful thought should be put into when and where to use them.