What is GORM and what are its core features?

GORM (Go Object-Relational Mapping) is one of the most popular ORM libraries in the Go language, providing powerful database operation capabilities.

Core Features

1. Full-featured ORM: Supports associations, hooks, preloading, transactions, and more
2. Associations: Supports Has One, Has Many, Many To Many, Belongs To relationships
3. Hooks: Supports Before/After Create, Save, Update, Delete, Find hooks
4. Auto Migration: Supports automatic table creation, foreign keys, indexes, etc.
5. Chainable API: Provides fluent API design with chainable operations
6. Multi-database Support: MySQL, PostgreSQL, SQLite, SQL Server, etc.

Basic Usage Example

go
// Define model
type User struct {
    gorm.Model
    Name  string
    Email string `gorm:"type:varchar(100);uniqueIndex"`
    Age   int
}

// Connect to database
db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})

// Create record
db.Create(&User{Name: "John", Email: "john@example.com", Age: 30})

// Query record
var user User
db.First(&user, 1) // Query record with primary key 1

// Update record
db.Model(&user).Update("Age", 31)

// Delete record
db.Delete(&user)

Common Methods

• First(): Query first record
• Find(): Query multiple records
• Where(): Add query conditions
• Create(): Create record
• Update(): Update record
• Delete(): Delete record
• Preload(): Preload associated data
• Joins(): Execute JOIN queries

GORM follows the convention over configuration design philosophy, allowing developers to quickly perform database operations while maintaining code simplicity and maintainability.