# sequelize/sequelize

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30,342 stars · 4,321 forks · TypeScript · mit

## Links

- GitHub: https://github.com/sequelize/sequelize
- Homepage: https://sequelize.org/
- awesome-repositories: https://awesome-repositories.com/repository/sequelize-sequelize.md

## Topics

`db2-ibm-i` `feature-rich` `javascript` `mariadb` `microsoft-sql-server` `mssql` `mssql-server` `mysql` `nodejs` `oracle-db` `orm` `postgresql` `sequelize` `snowflakedb` `sql` `sqlite` `transactions` `typescript`

## Description

Sequelize is an object-relational mapping library that provides a unified interface for managing relational data through code. By implementing the Active Record pattern, it maps database tables to application objects, allowing developers to perform standard create, read, update, and delete operations using high-level method calls. The library abstracts complex database interactions by translating these calls into optimized, engine-specific SQL statements, ensuring consistent behavior across different database systems.

The project distinguishes itself through a comprehensive suite of tools for managing relational complexity and data integrity. It features a robust association system that supports one-to-one, one-to-many, and many-to-many relationships, including polymorphic associations and nested join mapping. To maintain consistency during complex operations, it includes an asynchronous transaction coordinator and a lifecycle management framework that triggers custom logic through hooks and validation rules. Furthermore, it provides a schema synchronization engine that aligns application model definitions with the underlying database structure, supporting versioned migrations to track changes over time.

Beyond its core mapping capabilities, the library offers extensive support for database management and performance tuning. This includes connection pooling to manage concurrent requests, read replication for distributed query operations, and query scopes for reusable data retrieval patterns. It also provides native support for TypeScript, allowing for type-safe data definitions and model configurations. The library is designed for modular integration and includes utilities for query logging, custom data type definitions, and soft deletion.

## Tags

### Data & Databases

- [Object-Relational Mappers](https://awesome-repositories.com/f/data-databases/object-relational-mappers.md) — Maps database tables to application objects to provide a unified interface for managing relational data through code.
- [Database Drivers](https://awesome-repositories.com/f/data-databases/database-drivers.md) — Sequelize manages database connections by creating instances with specific parameters, verifying connection status, and handling the connection lifecycle. ([source](https://sequelize.org/docs/v6/getting-started))
- [Object-Relational Mapping](https://awesome-repositories.com/f/data-databases/object-relational-mapping.md) — Sequelize maps objects to database tables by extending a base class or using a factory method to define attributes and configuration. ([source](https://sequelize.org/docs/v6/category/core-concepts/))
- [Query Builders](https://awesome-repositories.com/f/data-databases/query-builders.md) — Sequelize provides a query builder that translates high-level object-oriented method calls into dialect-specific SQL statements for consistent database interactions.
- [Relational Mappings](https://awesome-repositories.com/f/data-databases/relational-mappings.md) — Sequelize connects database tables using one-to-one, one-to-many, or many-to-many relationships to manage complex data structures effectively. ([source](https://sequelize.org/docs/v6/category/core-concepts/))
- [Data Access Layers](https://awesome-repositories.com/f/data-databases/data-access-layers.md) — Sequelize manages model instances by performing create, read, update, and delete operations for individual database records. ([source](https://sequelize.org/docs/v6/core-concepts/model-instances/))
- [Relational Association APIs](https://awesome-repositories.com/f/data-databases/relational-association-apis.md) — Sequelize defines relationships between database models by calling association functions like belongsTo, hasOne, hasMany, or belongsToMany on a source model. ([source](https://sequelize.org/api/v6/identifiers))
- [Data Modeling](https://awesome-repositories.com/f/data-databases/data-modeling.md) — Sequelize supports assigning specific database-native types to model columns using built-in options that map directly to database definitions. ([source](https://sequelize.org/docs/v6/core-concepts/model-basics/))
- [Data Validation](https://awesome-repositories.com/f/data-databases/data-validation.md) — Sequelize defines model attributes using a type-safe system that validates data types by default and enforces strict constraints on values. ([source](https://sequelize.org/docs/v7/other-topics/upgrade-to-v7))
- [Database Migration Tools](https://awesome-repositories.com/f/data-databases/database-migration-tools.md) — "Compares model definitions against the current database state to automatically generate and execute migration scripts for structural alignment."
- [Database Transactions](https://awesome-repositories.com/f/data-databases/database-transactions.md) — Sequelize manages database transactions using asynchronous storage to enable automatic transaction tracking and atomic units of work. ([source](https://sequelize.org/docs/v7/other-topics/upgrade-to-v7))
- [Lifecycle Hooks](https://awesome-repositories.com/f/data-databases/lifecycle-hooks.md) — Sequelize allows executing custom logic automatically before or after specific model operations by registering functions that trigger during defined lifecycle events. ([source](https://sequelize.org/docs/v6/category/other-topics/))
- [Polymorphic Associations](https://awesome-repositories.com/f/data-databases/polymorphic-associations.md) — Sequelize enables polymorphic associations, allowing a single entity to belong to more than one other type of entity using a shared interface. ([source](https://sequelize.org/docs/v6/category/advanced-association-concepts/))
- [Schema Migration Tools](https://awesome-repositories.com/f/data-databases/schema-migration-tools.md) — A tool that aligns application model definitions with underlying database structures by automatically creating or altering tables to match configuration.
- [Transaction Managers](https://awesome-repositories.com/f/data-databases/transaction-managers.md) — Groups multiple database operations into atomic units of work using internal storage to ensure consistency across asynchronous execution flows.
- [Database Migrations](https://awesome-repositories.com/f/data-databases/database-migrations.md) — Sequelize tracks schema changes over time using versioned files that define state transitions and support reverting changes when necessary. ([source](https://sequelize.org/docs/v6/category/other-topics/))
- [Connection Pools](https://awesome-repositories.com/f/data-databases/connection-pools.md) — Sequelize configures connection pooling during initialization to manage multiple database connections efficiently from a single process. ([source](https://sequelize.org/docs/v6/category/other-topics/))
- [Database Dialect Adapters](https://awesome-repositories.com/f/data-databases/database-dialect-adapters.md) — Sequelize interacts with specific database systems using dialect-specific query interfaces that handle unique communication requirements for various supported engines. ([source](https://sequelize.org/api/v6/identifiers))
- [Database Dialects](https://awesome-repositories.com/f/data-databases/database-dialects.md) — Sequelize connects to specific database engines by importing dedicated dialect packages to reduce main package size and remove manual driver installation requirements. ([source](https://sequelize.org/docs/v7/other-topics/upgrade-to-v7))
- [Association Scoping](https://awesome-repositories.com/f/data-databases/association-scoping.md) — Sequelize allows applying predefined conditions to related records to ensure only specific data is returned when querying through established associations. ([source](https://sequelize.org/docs/v6/category/advanced-association-concepts/))
- [Custom Data Types](https://awesome-repositories.com/f/data-databases/custom-data-types.md) — Sequelize enables defining specialized data formats by extending base functionality when standard options do not meet specific database requirements. ([source](https://sequelize.org/docs/v6/category/other-topics/))
- [Database Access Layers](https://awesome-repositories.com/f/data-databases/database-access-layers.md) — Sequelize executes raw queries by running custom or pre-prepared database commands directly when standard abstraction methods do not meet specific requirements. ([source](https://sequelize.org/docs/v6/category/core-concepts/))
- [Database Performance Optimizers](https://awesome-repositories.com/f/data-databases/database-performance-optimizers.md) — Sequelize optimizes database performance by implementing batching and caching strategies to reduce server load and improve response times. ([source](https://sequelize.org/docs/v7/other-topics/resources/))
- [Eager Loading](https://awesome-repositories.com/f/data-databases/eager-loading.md) — Sequelize loads related data from multiple models in a single database query using joins to reduce the number of round trips to the server. ([source](https://sequelize.org/docs/v6/category/advanced-association-concepts/))
- [Schema Migrations](https://awesome-repositories.com/f/data-databases/schema-migrations.md) — Sequelize supports automatic schema synchronization to keep the database structure in sync with application model definitions. ([source](https://sequelize.org/))

### Programming Languages & Runtimes

- [Type System Tools](https://awesome-repositories.com/f/programming-languages-runtimes/language-features-paradigms/type-system-tools.md) — Sequelize supports TypeScript projects with modern module resolution options, providing type definitions for standard runtime environments. ([source](https://sequelize.org/docs/v7/getting-started))

### System Administration & Monitoring

- [Query Logging](https://awesome-repositories.com/f/system-administration-monitoring/query-logging.md) — Sequelize allows developers to monitor database queries by providing custom handler functions for debugging or routing logs to external monitoring tools. ([source](https://sequelize.org/docs/v6/getting-started))