SchematicNeo4j 0.1.1-beta

SchematicNeo4j

A code-first approach to manage a consistent Neo4j graph schema for a domain layer that is defined in a .NET library.

For Developers

Defining your domain schema

Identifying Nodes and their Node Key

Annotate the class with a NodeAttribute (or it can also default to the class name)

[Node(Label = "Person")]
public class Class1 {}

public class Person {}

[Node]
public class Person {}

Annotate the properties that make up the Node Key

public class Car {
  [NodeKey]
  public string Make { get; set; }

  [NodeKey]
  public string Model { get; set;}
}

Using Shared (or inherited) Node Keys

If you want to differentiate between 2 subclasses of an object but they are going to share the same node key, defined by the super class. We can do something like this.

public class Person {
  [NodeKey]
  public string FirstName { get; set; }

  [NodeKey]
  public string LastName { get; set;}
}

[Node(Label="Person:Coach")]
public class Coach : Person {
  public int YearStarted {get; set;}
}

[Node(Label="Person:Player")]
public class Player : Person {
  public string Postion {get; set;}
}

Both players and coaches have a name; players can be coaches, and vice versa. Either way, this keeps our data clean preventing a person from having 2 records in the system.

SchematicNeo4j.Extensions

There are a few provided extensions that we can take advantage of when using the CustomAttributes. Assume the following Vehicle definition:

public class Vehicle {
  [NodeKey]
  public string Make { get; set; }

  [NodeKey]
  public string Model { get; set;}

  [NodeKey]
  public string ModelYear { get; set; }

}

We can get the Label by:

// for a type
var theLabel = typeof(Vehicle).Label();

We can get the Node Key properties by:

// for a type
List<string> vehicleNodeKey = typeof(Vehicle).NodeKey();

Using SchematicNeo4j.Schema.Initialize

Once we have our domain models identified we can use the Schema methods to put it into the graph. You can pass in either an entire assembly, a list, or a single Type.

// Pass an Assembly and driver
SchematicNeo4j.Schema.Initialize(assembly:Assembly.GetAssembly(typeof(DomainSample.Person)), driver);

// Pass a list of domain types
  // Get this assembly
  Assembly a = Assembly.GetExecutingAssembly();
  // Limit to a specific namespace.
  var listOfTypes = a.ExportedTypes.Where(t => t.Namespace == "MyExecutingThing.MyDomain").ToList();
  SchematicNeo4j.Schema.Initialize(listOfTypes, driver);