FAQ

General Questions

What databases does GoCRUD support?

GoCRUD supports:

• PostgreSQL
• MySQL
• SQLite
• Microsoft SQL Server

Does GoCRUD support PATCH operations?

Yes, through Huma's autopatch feature. Enable it with:

autopatch.AutoPatch(api)

Can I use custom field types?

Yes, by implementing the Operations method for custom filtering:

type CustomID int

func (_ *CustomID) Operations() map[string]func(string, ...string) string {
    return map[string]func(string, ...string) string{
        "_regexp": func(key string, values ...string) string {
            return fmt.Sprintf("%s REGEXP %s", key, values[0])
        },
    }
}

Common Issues

Why am I getting "unsupported database driver"?

Make sure you:

1. Import the correct database driver
2. Use the supported driver package:
   • PostgreSQL: github.com/lib/pq
   • MySQL: github.com/go-sql-driver/mysql
   • SQLite: github.com/mattn/go-sqlite3
   • MSSQL: github.com/microsoft/go-mssqldb

Why aren't my relations working?

Check that you:

1. Used the correct tag format:

   Documents []Document `db:"documents" src:"id" dest:"userId" table:"documents" json:"-"`
   

2. Set up the foreign key fields correctly
3. Have proper database permissions

Why isn't pagination working?

Ensure you're using both limit and skip:

GET /users?limit=10&skip=0

Best Practices

How should I structure my models?

Follow these guidelines:

1. Always define table name using the _ field:

   _    struct{} `db:"users" json:"-"`
   

2. Make ID fields pointers for proper null handling:

   ID   *int    `db:"id" json:"id"`
   

3. Use appropriate tags for validation:

   Age  *int    `db:"age" json:"age" minimum:"0" maximum:"120"`
   

How can I optimize performance?

1. Use bulk operations when possible
2. Set appropriate limits on queries
3. Add database indexes for filtered fields
4. Use relationship filtering judiciously

How should I handle errors?

1. Use hooks for validation:

   BeforePost: func(ctx context.Context, models *[]User) error {
       if err := validate(models); err != nil {
           return fmt.Errorf("validation failed: %w", err)
       }
       return nil
   }
   

2. Return specific error types
3. Log errors appropriately

Configuration

How do I disable certain operations?

Use operation modes in config:

config := &gocrud.Config[User]{
    GetMode:    gocrud.BulkSingle,
    PostMode:   gocrud.None,      // Disable POST
    DeleteMode: gocrud.None,      // Disable DELETE
}

How do I add custom validation?

Use before hooks:

BeforePost: func(ctx context.Context, models *[]User) error {
    for _, user := range *models {
        if err := customValidation(user); err != nil {
            return err
        }
    }
    return nil
}

Advanced Usage

Can I use transactions?

Transactions are handled automatically for:

• Bulk updates
• Bulk deletes
• Operations with hooks

How do I implement custom filtering?

1. Define custom operations on field types
2. Use the operations in queries:

   GET /users?where={"id":{"_regexp":"^10.*"}}
   

Can I extend the default operations?

Yes, by:

1. Implementing custom field types
2. Adding hooks for custom logic
3. Using the underlying repository interface

Troubleshooting

Common Error Messages

"entity not found"

• Check if the resource exists
• Verify the ID is correct
• Ensure proper database permissions

"invalid identifier type"

• Check model field types
• Ensure ID fields are properly defined
• Verify query parameter types

"validation failed"

• Check input data format
• Verify field constraints
• Look for missing required fields

Debug Tips

1. Enable debug logging
2. Check SQL queries in logs
3. Verify database connection
4. Test queries directly in database
5. Check hook execution order

Getting Help

Where can I find more examples?

Check the examples directory in the repository:

• Basic CRUD
• Relations
• Custom operations
• Different databases
• Hooks implementation

How do I report issues?

1. Check existing issues on GitHub
2. Provide minimal reproduction
3. Include:
   • Go version
   • Database type and version
   • Complete error message
   • Example code