Global Query Filters in EF Core

What are Global Query Filters?

Global query filters are LINQ predicates automatically applied to all queries for an entity type. They’re useful for implementing soft delete, multi-tenancy, and other cross-cutting concerns.

Basic Usage

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Product>()
        .HasQueryFilter(p => !p.IsDeleted);
}

// All queries automatically filter deleted products
var products = context.Products.ToList(); // WHERE IsDeleted = 0

Soft Delete Implementation

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public DateTime? DeletedAt { get; set; }
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Product>()
        .HasQueryFilter(p => !p.IsDeleted);
}

// Soft delete
var product = await context.Products.FindAsync(id);
product.IsDeleted = true;
product.DeletedAt = DateTime.UtcNow;
await context.SaveChangesAsync();

Multi-Tenancy

public interface ITenantEntity
{
    int TenantId { get; set; }
}

public class Product : ITenantEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int TenantId { get; set; }
}

public class ApplicationDbContext : DbContext
{
    private readonly int _currentTenantId;
    
    public ApplicationDbContext(DbContextOptions options, ITenantProvider tenantProvider)
        : base(options)
    {
        _currentTenantId = tenantProvider.GetCurrentTenantId();
    }
    
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Product>()
            .HasQueryFilter(p => p.TenantId == _currentTenantId);
    }
}

Ignoring Query Filters

// Ignore all query filters
var allProducts = context.Products
    .IgnoreQueryFilters()
    .ToList();

// Include deleted products
var deletedProducts = context.Products
    .IgnoreQueryFilters()
    .Where(p => p.IsDeleted)
    .ToList();

Multiple Filters

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Product>()
        .HasQueryFilter(p => !p.IsDeleted && p.TenantId == _currentTenantId);
}

Navigation Property Filters

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Blog>()
        .HasQueryFilter(b => !b.IsDeleted);
    
    modelBuilder.Entity<Post>()
        .HasQueryFilter(p => !p.IsDeleted);
}

// Both filters applied
var blogs = context.Blogs
    .Include(b => b.Posts)
    .ToList();

Summary

Global query filters in EF Core automatically apply LINQ predicates to all queries for an entity. They’re ideal for soft delete, multi-tenancy, and security. Use IgnoreQueryFilters() to bypass them when needed.