When building full-fledged applications, it is almost guaranteed that you will be required to work with a database. Such an application will need to implement CRUD, which is the ability to Create, Read, Update, and Delete data.
Object Relational Mapper(ORM)
An ORM is a tool that allows developers to work with relational databases using object-oriented principles.
An ORM act as a bridge between the application code and the relational database of choice, allowing developers to work with relational databases using the same object-oriented principles they use in their application code.
ORMs map relational database tables to classes with class instances representing the records or rows in the table. Class attributes are used to represent columns in a table.
This, in turn, means that developers can use their programming language of choice to create, read, update, delete, and also manage the data stored in the database without the need to write complex SQL statements.
By using an ORM, you minimize the amount of SQL you’ll need to read and also avoid learning a new querying language in order to work with a database.
To see how an ORM works, consider the following MySQL query to find users from the IT department
SELECT * FROM users WHERE department = 'IT';
Abstraction of Database Complexities
ORMs mask away the complexities of the underlying database allowing developers to interact with the database through your backend language and not complex SQL.
Some ORMs also provide query builders, which make writing complex queries a breeze through the use of OOP principles. This allows developers to write cleaner, more maintainable code that is easier to debug and update.
ORMs abstract away the complexities of writing raw SQL queries and managing database interactions allowing developers to solely focus on the business logic of the application, which is the most important part of an application.
Additionally, developers interact with databases in a more familiar OOP pattern without the need to write a lot of boilerplate code or perform repetitive tasks.
ORMs can also be used to automatically seed databases and generate data access codes. All these factors greatly augment the productivity of developers.
A key feature of ORMs is that they allow you to write your application code in a database-agnostic manner. This way, your application code is not pegged on a single database, and thus you can easily switch the database your application is using without the need to change large parts of your application code.
This is very important, particularly when an application needs to evolve or support the use of multiple databases.
Easy Schema and Relationship Management
ORMs simplify the process of working with Schemas in your database and managing relationships between your database entities.
Some ORMs offer features such as automatic schema generation from existing databases, and a majority provide methods that allow you to easily define and manage relationships among tables stored in the database.
ORM offers enhanced database security as they filter data for you and also use parameterized queries internally. Parameterized queries are SQL queries that use placeholders for input values instead of directly using the input provided by a user.
Therefore user-provided input is never directly embedded into an SQL query. This allows ORM to shield your application from SQL injection attacks and thus enhance the security of your application.
Drawbacks of using an ORM
As much as ORMs have lots of benefits for developers, there are some drawbacks associated with their use. For once, since they introduce a layer of abstraction on top of the database, it may result in performance overhead and the use of more memory.
Additionally, to use an ORM, developers need to learn how to use it, and they can’t use an ORM without a basic understanding of SQL in order to know what each command actually does.
According to its official documentation, Sequelize is a modern TypeScript and Node.js ORM for Oracle DB, PostgreSQL, MySQL, MariaDB, SQLite, Microsoft SQL Server, IBM DB2, and Snowflake database. Sequelize, which is open-source, is a very popular ORM for developers working with the Node.js framework together with relational databases.
This can be attributed to its robust set of features which make working with relational databases in Node.js a breeze. First, Sequelize is a promised-based ORM, a feature that allows it to support promises which are a core feature of the Node.js framework.
Additionally, Sequelize supports eager loading, where resources are loaded as soon as the application code is executed, and lazy loading, where resources are not immediately loaded until they are needed. Sequelize also has solid transaction support, read replication, and model validations, and it allows for database migrations and synchronization.
Users can also define associations and relations among modes when using Sequelize. To cap it all, provides a rich set of querying options, allowing developers to construct complex database queries with ease.
To help developers build queries, Prisma has a feature called Prisma client which comes with auto-completion and allows developers to build type-safe queries that are tailored to the schema they are using in their application.
Developers can create their own schema from scratch or use Prisma to autogenerate schema by introspecting an existing database.
Another Prisma feature is Prisma migrate, which is a Prisma schema migration tool that auto-generates customizable SQL migrations allowing users to have full control and flexibility when taking their applications from development to production environments.
TypeORM supports MySQL, MariaDB, PostgreSQL, CockroachDB, SQLite, Microsoft SQL Server, Oracle, SAP Hana, and sql.js databases.
TypeORM allows developers to work with multiple database types and use multiple database instances. It also supports and query caching, logging, transactions, associations, eager and lazy relations and allows for migrations and automatic migrations generation.
TypeORM also supports DataMapper, ActiveRecord, streaming raw results, cross-database, and cross-schema queries and offers users a powerful query builder.
MikroORM is an open-source TypeScript ORM that supports MySQL, MariaDB, PostgreSQL, SQLite, and MongoDB. This ORM is based on Datamapper, Identity Map Pattern, and Unit of Work. Unit of work is used to maintain a list of entities affected by a business transaction, and it also coordinates the writing of the changes.
This has the benefit of allowing the automatic handling of transactions, automatic batching of all queries, and direct implementation of business/domain logic directly in the entities used.
MikroORM also comes with a metadata-aware QueryBuilder with auto-joining support and an event system that can be used to hook into the entity lifecycle and also alter how the UnitOfWork works.
Seeding databases, that is, populating a database with an initial set of data, is also easier with MikroORM as it comes with a seeder that allows you to generate fake data of any volume or shape and use it to seed your database.
Finally, MikroORM also supports easy up-and-down database migrations.
Being a Node.js ORM, Bookshelf supports the use of promises and traditional callbacks when working with the ORM from a Node.js application. Additionally, it supports transactions, polymorphic associations, eager/nested-eager relation loading, and a variety of relations.
Node ORM2 is a simple and lightweight Node.js ORM that supports MySQL, SQLite, and Progress OpenEdge databases. This ORM allows you to easily work with your models in Node.js. When working with models, it allows you to easily create, sync, drop, get, find, remove, count, and also bulk create data models.
It also allows the creation of associations between models and defining custom validations in addition to the built-in validations that come with it. Node ORM2 implements the instance singleton behavior, which ensures that when you fetch the same row multiple times, you always get the same object representing that row.
Waterline is an adapter-based ORM for Node.js. It is also the default ORM that comes with the Sails web development framework. However, Waterline can still be used without using the Sails framework.
Being an adapter-based ORM, Waterline provides support for working with multiple database systems through the use of adapters. Officially supported databases include MySQL, PostgreSQL, MongoDB, Redis, and local storage.
However, Waterline also has community adapters for CouchDB, SQLite, Oracle, Microsoft SQL Server, DB2, Riak, neo4j, OrientDB, Amazon RDS, DynamoDB, Azure Table,s RethinkDB, and Solr.
Waterline allows you to use more than one database in your project, and it provides a uniform API for working with different databases and protocols. This means that code written using Waterline ORM can work with any database supported by the ORM without the need to change your code.
Additionally, Waterline is created with an emphasis on modularity, testability, and consistency across adapters, making it very easy to use and integrate with a variety of databases.
Objection.js is an ORM that aims to stay out of your way and make it easy to use the full power of SQL and the underlying database engine.
In that regard, it offers all the benefits of an SQL query builder and is powerful to help you work with relations. An SQL query builder is a tool that simplifies the process of creating complex SQL queries.
Objection.js offers an easy way of defining models and relationships between them, with full Create, Read, Update Delete (CRUD) capabilities that utilize the full power of SQL, in addition to offering easy-to-use transactions.
This will not only simplify the database interactions but also increase your productivity, reduce the SQL you need to write, and enhance the security of your application.
When trying to decide on what ORM to use, consider using any of the ORMs highlighted in the article, depending on what features suit the application you’re building.
Collins Kariuki is a software developer and technical writer for Geekflare. He has over four years experience in software development, a background in Computer Science and has also written for Argot, Daily Nation and the Business Daily Newspaper.
Narendra Mohan Mittal
Narendra Mohan Mittal is a Senior Digital Branding Strategist and Content Editor with over 12 years of versatile experience. He holds an M-Tech (Gold Medalist) and B-Tech (Gold Medalist) in Computer Science & Engineering.
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