GORM Querying in Modern Grails

Modern GORM Features

GORM in Grails 5/6/7 includes performance improvements, better query optimization, and enhanced support for both blocking and non-blocking data access.

Basic Queries

// Static methods
Book.list()                    // All books
Book.list(max: 10, offset: 5) // Pagination
Book.get(1)                    // By ID
Book.findByName("Groovy")     // Dynamic finder

// Criteria queries
Book.createCriteria().list {
    eq('author', 'Smith')
    gt('pages', 200)
    order('title', 'asc')
}

HQL Queries

// Hibernate Query Language
Book.executeQuery("from Book b where b.author = :author", [author: "Smith"])

// Projections
Book.executeQuery("select b.author, count(b) from Book b group by b.author")

Named Queries

class Book {
    String title
    String author
    int pages

    static namedQueries = {
        byAuthor { String author ->
            eq('author', author)
        }
        popularBooks {
            gt('pages', 300)
        }
    }
}

// Usage
Book.byAuthor("Smith").list()
Book.popularBooks().list(max: 5)

Query Performance

GORM 6+ includes query caching and batch loading improvements:

static mapping = {
    cache true  // Enable query caching
    batchSize 10  // Batch loading
}

Key Points

• GORM provides static methods, dynamic finders, and criteria queries.
• HQL offers powerful query capabilities beyond dynamic finders.
• Named queries encapsulate reusable query logic.
• Query caching and batch loading improve performance.
• GORM 6+ includes non-blocking query support.