ClosureTable

Store self-referencing hierarchies with .NET and Entity Framework.

Getting Started

Examples

Test Model And Data

The following model is used for integration testing (TODO link):

public class TestEntity : SelfReferencingEntity<TestEntity, Guid>
{
    public string Name { get; }

    public TestEntity(TestEntity? parent, string name) : base(parent)
    {
        Name = name;
    }

    // Required for EF constructor binding. See: https://github.com/dotnet/efcore/issues/12078
    private TestEntity()
    {
        Name = default!;
    }
}

The following data is used for integration testing (TODO link):

roots:  A    B    C    D    E    F    G    H    I
                                                |
                                           .--+-+-+--.
                                          |   |   |   |
                                          J   M   N   O
                                          |
                                          K
                                          |
                                          L

Root / Parent

C#	Value
context.TestEntities.Roots<TestEntity, Guid>()	[A, B, C, D, E, F, G, H, I]

Let var a = context.TestEntities.First(e => e.Name == "A"):

C#	Value
a.IsRoot	true
a.IsParent	false

Let var i = context.TestEntities.First(e => e.Name == "I"):

C#	Value
i.IsRoot	true
i.IsParent	true

Let var k = context.TestEntities.First(e => e.Name == "K"):

C#	Value
k.IsRoot	false
k.IsParent	true

Let var l = context.TestEntities.First(e => e.Name == "L"):

C#	Value
l.IsRoot	false
l.IsParent	false

Children

Let var i = context.TestEntities.First(e => e.Name == "I"):

C#	Value
i.Children	[J, M, N, O]
i.Children.Count	3
i.Children.Any()	true

Let var l = context.TestEntities.First(e => e.Name == "I"):

C#	Value
l.Children	[]
l.Children.Count	0
l.Children.Any()	false

Ancestors

Let var i = context.TestEntities.First(e => e.Name == "I"):

C#	Value
i.Ancestors	[I]
i.Ancestors.Count	1
i.Ancestors.Any()	true
i.AncestorsWithoutSelf	[]
i.AncestorsWithoutSelf.Count	0
i.AncestorsWithoutSelf.Any()	false
context.HasAncestors<TestEntity, Guid>(i.Id)	false
await context.HasAncestorsAsync<TestEntity, Guid>(i.Id)	false
context.AncestorsCount<TestEntity, Guid>(i.Id)	0
await context.AncestorsCountAsync<TestEntity, Guid>(i.Id)	0
context.AncestorsOf<TestEntity, Guid>(i.Id, withSelf: true)	[I]
context.AncestorsOf<TestEntity, Guid>(i.Id, withSelf: false)	[]

Let var l = context.TestEntities.First(e => e.Name == "L"):

C#	Value
l.Ancestors	[I, J, K, L]
l.Ancestors.Count	4
l.Ancestors.Any()	true
l.AncestorsWithoutSelf	[I, J, K]
l.AncestorsWithoutSelf.Count	3
l.AncestorsWithoutSelf.Any()	true
context.HasAncestors<TestEntity, Guid>(l.Id)	true
await context.HasAncestorsAsync<TestEntity, Guid>(l.Id)	true
context.AncestorsCount<TestEntity, Guid>(l.Id)	3
await context.AncestorsCountAsync<TestEntity, Guid>(l.Id)	3
context.AncestorsOf<TestEntity, Guid>(i.Id, withSelf: true)	[I, J, K, L]
context.AncestorsOf<TestEntity, Guid>(i.Id, withSelf: false)	[I, J, K]

Descendants

Let var i = context.TestEntities.First(e => e.Name == "I"):

C#	Value
i.Descendants	[I, J, K, L, M, N, O]
i.Descendants.Count	7
i.Descendants.Any()	true
i.DescendantsWithoutSelf	[J, K, L, M, N, O]
i.DescendantsWithoutSelf.Count	6
i.DescendantsWithoutSelf.Any()	true
context.HasDescendants<TestEntity, Guid>(i.Id)	true
await context.HasDescendantsAsync<TestEntity, Guid>(i.Id)	true
context.DescendantsCount<TestEntity, Guid>(i.Id)	6
await context.DescendantsCountAsync<TestEntity, Guid>(i.Id)	6
context.DescendantsOf<TestEntity, Guid>(i.Id, withSelf: true)	[I, J, K, L, M, N, O]
context.DescendantsOf<TestEntity, Guid>(i.Id, withSelf: false)	[J, K, L, M, N, O]

Let var l = context.TestEntities.First(e => e.Name == "L"):

C#	Value
l.Descendants	[L]
l.Descendants.Count	1
l.Descendants.Any()	true
l.DescendantsWithoutSelf	[]
l.DescendantsWithoutSelf.Count	0
l.DescendantsWithoutSelf.Any()	false
context.HasDescendants<TestEntity, Guid>(l.Id)	false
await context.HasDescendantsAsync<TestEntity, Guid>(l.Id)	false
context.DescendantsCount<TestEntity, Guid>(l.Id)	0
await context.DescendantsCountAsync<TestEntity, Guid>(l.Id)	0
context.DescendantsOf<TestEntity, Guid>(i.Id, withSelf: true)	[L]
context.DescendantsOf<TestEntity, Guid>(i.Id, withSelf: false)	[]

See Also

Curiously Recurring Template Pattern

• Modern C# Techniques, Part 1: Curiously Recurring Generic Pattern by Stephen Cleary
• Curiouser and curiouser by Eric Lippert