GORM Plus

A type-safe generic base model pattern implementation for GORM, providing a clean and consistent interface for common database operations.

Features

• Type-safe operations: Generic implementation ensures compile-time type safety
• Transaction support: Built-in transaction management with automatic rollback
• Flexible querying: Composable scope functions for building complex queries
• Pagination: Built-in pagination support with configurable page sizes
• Soft delete support: Full support for GORM's soft delete functionality
• Row locking: SELECT FOR UPDATE support for concurrent access control
• Batch operations: Efficient batch insert operations with configurable batch sizes

Installation

go get github.com/nullcache/gorm-plus

Quick Start

package main

import (
    "context"
    "log"

    "github.com/nullcache/gorm-plus"
    "gorm.io/driver/sqlite"
    "gorm.io/gorm"
)

type User struct {
    ID    uint   `gorm:"primaryKey"`
    Name  string `gorm:"not null"`
    Email string `gorm:"unique;not null"`
    Age   int    `gorm:"default:0"`
}

func main() {
    // Initialize database
    db, err := gorm.Open(sqlite.Open("test.db"), &gorm.Config{})
    if err != nil {
        log.Fatal(err)
    }

    // Auto migrate
    db.AutoMigrate(&User{})

    // Create base model
    userBaseModel, err := gormplus.NewBaseModel[User](db)
    if err != nil {
        log.Fatal(err)
    }

    ctx := context.Background()

    // Create a user
    user := &User{Name: "John Doe", Email: "[email protected]", Age: 30}
    err = userBaseModel.Create(ctx, nil, user)
    if err != nil {
        log.Fatal(err)
    }

    // Find user by email
    foundUser, err := userBaseModel.First(ctx, gormplus.Where("email = ?", "[email protected]"))
    if err != nil {
        log.Fatal(err)
    }

    log.Printf("Found user: %+v", foundUser)
}

Core Components

Base Model

The BaseModel[T] type is the main component that provides database operations for entities of type T.

// Create a new base model instance
userBaseModel, err := gormplus.NewBaseModel[User](db)

Scopes

Scopes are composable functions that modify GORM queries:

// Basic conditions
users, err := userBaseModel.List(ctx,
    gormplus.Where("age > ?", 25),
    gormplus.Order("name ASC"),
    gormplus.Limit(10),
)

// Map-based conditions
users, err := userBaseModel.List(ctx,
    gormplus.WhereEq(map[string]any{
        "active": true,
        "role":   "admin",
    }),
)

Available Scopes

• Where(query, args...) - Add WHERE conditions
• WhereEq(map[string]any) - Add equality conditions from map
• Order(string) - Add ORDER BY clause
• Select(columns...) - Select specific columns
• Limit(int) - Limit number of results
• Offset(int) - Skip number of results
• WithDeleted() - Include soft-deleted records
• OnlyDeleted() - Only soft-deleted records

Operations

CRUD Operations

// Create
user := &User{Name: "Jane Doe", Email: "[email protected]"}
err := userBaseModel.Create(ctx, nil, user)

// Update
user.Age = 25
err = userBaseModel.Update(ctx, nil, user)

// Delete (soft delete if DeletedAt field exists)
err = userBaseModel.Delete(ctx, nil, gormplus.Where("id = ?", user.ID))

Query Operations

// Find first record
user, err := userBaseModel.First(ctx, gormplus.Where("email = ?", "[email protected]"))

// List records
users, err := userBaseModel.List(ctx,
    gormplus.Where("age > ?", 18),
    gormplus.Order("name ASC"),
)

// Count records
count, err := userBaseModel.Count(ctx, gormplus.Where("active = ?", true))

// Check existence
exists, err := userBaseModel.Exists(ctx, gormplus.Where("email = ?", "[email protected]"))

Pagination

// Get paginated results
result, err := userBaseModel.Page(ctx, 1, 20, // page 1, 20 items per page
    gormplus.Where("active = ?", true),
    gormplus.Order("created_at DESC"),
)

// Access pagination info
fmt.Printf("Page: %d/%d, Total: %d, HasNext: %v",
    result.Page,
    (result.Total + int64(result.PageSize) - 1) / int64(result.PageSize),
    result.Total,
    result.HasNext,
)

Batch Operations

users := []*User{
    {Name: "User 1", Email: "[email protected]"},
    {Name: "User 2", Email: "[email protected]"},
    {Name: "User 3", Email: "[email protected]"},
}

// Batch insert with default batch size (1000)
err := userBaseModel.BatchInsert(ctx, nil, users)

// Batch insert with custom batch size
err = userBaseModel.BatchInsert(ctx, nil, users, 100)

Transactions

// Manual transaction management
err := userBaseModel.Transact(ctx, func(ctx context.Context, tx *gorm.DB) error {
    user1 := &User{Name: "User 1", Email: "[email protected]"}
    if err := userBaseModel.Create(ctx, tx, user1); err != nil {
        return err
    }

    user2 := &User{Name: "User 2", Email: "[email protected]"}
    if err := userBaseModel.Create(ctx, tx, user2); err != nil {
        return err
    }

    return nil // Commit transaction
})

// Row locking (requires transaction)
err = db.Transaction(func(tx *gorm.DB) error {
    user, err := userBaseModel.FirstForUpdate(ctx, tx, gormplus.Where("id = ?", 1))
    if err != nil {
        return err
    }

    // Modify user safely
    user.Balance += 100
    return userBaseModel.Update(ctx, tx, &user)
})

Error Handling

The library defines several standard errors:

// Check for specific errors
user, err := userBaseModel.First(ctx, gormplus.Where("id = ?", 999))
if errors.Is(err, gormplus.ErrNotFound) {
    // Handle not found case
}

// Available errors:
// - gormplus.ErrInvalidType: Invalid generic type
// - gormplus.ErrNotFound: Record not found
// - gormplus.ErrTxRequired: Transaction required for operation
// - gormplus.ErrDangerous: Dangerous operation (e.g., delete without conditions)

Best Practices

1. Always use contexts: Pass context for cancellation and timeout support
2. Handle transactions properly: Use the Transact method for complex operations
3. Validate inputs: Check for required conditions before dangerous operations
4. Use appropriate scopes: Combine scopes to build precise queries
5. Handle errors: Always check for specific error types when needed

Requirements

• Go 1.19 or higher
• GORM v1.25.0 or higher

License

MIT License. See LICENSE file for details.

Contributing

Contributions are welcome. Please ensure all tests pass and follow the existing code style.