Compiled Queries

Temel Compiled Query

// Static field olarak tanımla — uygulama ömrü boyunca derleme 1 kere yapılır
public static class ProductQueries
{
    // Tek parametre
    public static readonly Func<AppDbContext, int, Task<Product?>> GetById =
        EF.CompileAsyncQuery(
            (AppDbContext ctx, int id) =>
                ctx.Products.FirstOrDefault(p => p.Id == id));

    // Birden fazla parametre
    public static readonly Func<AppDbContext, int, decimal, IAsyncEnumerable<Product>> 
        GetByCategoryAndMinPrice =
        EF.CompileAsyncQuery(
            (AppDbContext ctx, int categoryId, decimal minPrice) =>
                ctx.Products
                    .Where(p => p.CategoryId == categoryId && p.Price >= minPrice)
                    .OrderBy(p => p.Price));

    // Include ile
    public static readonly Func<AppDbContext, int, Task<Product?>> GetWithCategory =
        EF.CompileAsyncQuery(
            (AppDbContext ctx, int id) =>
                ctx.Products
                    .Include(p => p.Category)
                    .FirstOrDefault(p => p.Id == id));
}

Kullanım

// Controller/Service'de
public class ProductService
{
    private readonly AppDbContext _context;

    public async Task<Product?> GetByIdAsync(int id)
    {
        // ✅ Her çağrıda expression tree parse edilmez
        return await ProductQueries.GetById(_context, id);
    }

    public async Task<List<Product>> GetExpensiveInCategoryAsync(int catId, decimal min)
    {
        var results = new List<Product>();
        await foreach (var product in ProductQueries.GetByCategoryAndMinPrice(_context, catId, min))
        {
            results.Add(product);
        }
        return results;
    }
}

Ne Zaman Compiled Query Kullan?

Kısıtlamalar:

• Dynamic where/orderby kullanılamaz
• Skip/Take parametrik yapılamaz (EF Core 8+: kısıtlı destek)
• Global Query Filter'lar otomatik uygulanır