I'm using EF Core for my project. And I have a problem with nested query in EF Core.
I have 2 classes:
public class PermissionGroupDefinitionEntity : IEntity
{
public string Name { get; set; }
public string NormalizedName { get; set; }
public string DisplayName { get; set; }
public virtual ICollection<PermissionDefinitionEntity> PermissionDefinitions { get; set; }
}
public class PermissionDefinitionEntity : IEntity
{
public string Name { get; set; }
public string NormalizedName { get; set; }
public string DisplayName { get; set; }
public bool IsEnabled { get; set; }
public virtual string GroupName { get; set; }
public virtual PermissionGroupDefinitionEntity Group { get; set; }
public virtual ICollection<PermissionDefinitionEntity> Children { get; set; }
}
and this is the ApplicationDbContext:
builder.Entity<PermissionDefinitionEntity>().HasOne(r => r.Group).WithMany(r => r.PermissionDefinitions).OnDelete(DeleteBehavior.Cascade);
builder.Entity<PermissionDefinitionEntity>().HasOne(r => r.Parent).WithMany(r => r.Children).OnDelete(DeleteBehavior.Cascade);
I want query all PermissionGroupDefinitionEntity
included PermissionDefinitionEntity
and self referencing of PermissionDefinitionEntity
.
Can I do that with EF Core?
You need to load recursively PermissionDefinitions that placed in the PermissionGroupDefinitionEntity.
First, you should load all PermissionGroupDefinitionEntities includes it's children like following query :
var query = _dbContext.PermissionGroupDefinitionEntity
.AsNoTracking()
.Include(p => p.PermissionDefinitions )
.ThenInclude(p => p.Children)
.ToListAsync();
Since every PermissionGroupDefinitionEntity has a list of PermissionDefinition you need nested loops like following code :
foreach (var PermissionGroupDefinitionEntity in PermissionGroupDefinitionEntities)
{
foreach (var PermissionDefinitions in PermissionDefinitions)
{
}
}
Then in the inner loop you should call your recursive function. See following link (Sample for Get all children recursively in Entity Framework Core)
This way has terrible performance and I don't recommend that.
In this case it's seems you must write store procedure in sql for better performance.
You can use .ThenInclude(i => ...)
like so
var query = _context.PermissionGroupDefinitionEntity
.AsNoTracking()
.Include(i => i.PermissionDefinitions)
.ThenInclude(i => i.Group)
.AsQueryable();
Edit:
var query = _context.PermissionGroupDefinitionEntity
.AsNoTracking()
.Include(i => i.PermissionDefinitions)
.ThenInclude(i => i.Children)
.AsQueryable();
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