How to Manage a Many to Many Relationship in Flutter with SQLite

Learn how to efficiently handle `many to many` relationships in Flutter using SQLite for organizing your school courses and semesters.
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How to Manage a Many to Many Relationship in Flutter with SQLite

In the world of app development, especially when dealing with educational apps, managing relationships between data is essential. A common scenario arises when you need to manage a many to many relation between entities, such as courses and semesters. In this guide, we will guide you through the process of implementing this relationship in your Flutter app using SQLite.

Understanding the Problem

Let’s take a look at the scenario: You are building an app to organize your school life, where you want to manage multiple courses and semesters. The relationships you want to establish are:

A semester can contain multiple courses.

A course can belong to multiple semesters.

This gives rise to a many to many relationship. To effectively manage this in SQLite, we need to understand how to set up our database schema and handle queries.

Setting Up Your Data Models

Defining the Course and Semester Classes

You already have basic classes defined for Course and Semester. Here’s a brief overview of each:

Course Class

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Semester Class

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Initializing the Database

You have also initialized your SQLite database with courses and semesters tables. However, to manage the many to many relationship, we need an additional table that links the two.

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Building the Many to Many Relationship

Creating the Linking Table

To manage the many to many relationship, we need to create a new table called SemesterEntries. This table will simply link semester IDs to course IDs.

Defining the SemesterWithCourses Class

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Querying and Inserting Data

With the data models set up, you can now query and insert data into your database. Here's how you can do it:

Watching All Semesters

This function will help you keep track of all semesters and their related courses in real time:

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Inserting a Semester and Its Courses

In your insert operation, you'll use a transaction to ensure that both semestery and course entries are managed properly:

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Conclusion

By using the Moor library and defining a linking table, you can efficiently manage a many to many relationship between courses and semesters in your Flutter application. Following the laid out steps gives you a structured way to organize your academic life effectively.

Now you're ready to implement this in your own Flutter application! Enjoy managing your courses and semesters like a pro!