JavaScript Object-Relational Mapping (ORM) software is a powerful tool for developers that allows them to interact with relational databases using JavaScript objects. These tools simplify the process of querying and manipulating database data, making it easier to work with databases in web applications.

There are numerous JavaScript ORM software options available, both paid and free. In this article, we will focus on the best free and open source JavaScript ORM software that developers can use to streamline their database interactions.

1. Sequelize:
Sequelize is one of the most popular ORM libraries for Node.js, supporting multiple databases including MySQL, PostgreSQL, SQLite, and others. It provides a simple API for defining models and performing CRUD operations, making it easy to work with database entities in Node.js applications. Sequelize also supports advanced features like transactions, hooks, and associations, making it a versatile choice for developers.

2. Bookshelf.js:
Bookshelf.js is a lightweight ORM library built on top of the Knex SQL query builder. It provides a clean and elegant API for defining database models and relationships, making it easy to work with complex data structures. Bookshelf.js is designed to be flexible and extensible, allowing developers to customize its behavior to suit their needs.

3. Waterline:
Waterline is a data modeling and ORM library that supports multiple databases including MySQL, PostgreSQL, and MongoDB. It provides a uniform API for interacting with different types of databases, making it easy to switch between them without changing your code. Waterline also supports data validation, aggregation, and querying, making it a powerful tool for building scalable applications.

4. Objection.js:
Objection.js is a minimalistic ORM library for Node.js that is built on top of the Knex query builder. It provides a simple yet powerful API for defining database models and relationships, making it easy to work with complex data structures. Objection.js also supports advanced features like eager loading, transactions, and JSON serialization, making it a flexible choice for developers.

5. TypeORM:
TypeORM is a powerful ORM library for TypeScript and JavaScript that supports multiple databases including MySQL, PostgreSQL, and MongoDB. It provides a rich set of features including entity modeling, validation, query building, and migrations, making it a comprehensive solution for database interactions. TypeORM also supports TypeScript decorators for defining entities, making it easy to work with complex data structures.

In conclusion, developers have a variety of free and open source JavaScript ORM software options to choose from when working with relational databases in their applications. Each of the software tools mentioned in this article has its own strengths and features, so developers should evaluate them based on their specific needs and requirements. Regardless of which ORM software developers choose, they can be confident that they will have a powerful tool at their disposal for simplifying and streamlining their database interactions.