Entities

Overview

Entities are the high-level business objects in your enterprise. For example, employee, product, purchase order, or department.

In MarkLogic Data Hub, you can use MarkLogic's Entity Services to create models of your business entities and to generate code scaffolding, database configurations, index settings, and validations based on those models. Entity Services handles the model definition and entity instance envelope documents through API calls. If you use your own abstract entities, you must provide this framework.

MarkLogic Data Hub groups all the data about an entity into one consolidated record (with context and history), thereby providing a 360° view of data, across silos.

Complex Entities

You can define your entity model to include another entity or to link to another.

• A local entity reference refers to an entity that is nested within the host entity as the value of a property. Use a nested entity if the values of its properties will change for every host entity. For example, an entity FullName can be nested in the entity Employee, because each employee would have a different full name.
• An external entity reference refers to an entity that is stored separately, and the host entity contains only a link to it. Link to an entity if the values of its properties must remain the same for all host entities. For example, an entity Product can be linked in the entity Order, because the SKU and product description will be the same for all customer orders.

• When mapping a nested entity (local entity reference), the type of the source data element must match one of the following:
  • an object, if Cardinality is set to 1..1, or
  • an array of objects, if Cardinality is set to 1..∞.
• When mapping a linked entity (external entity reference), the type of the source data element must be a string which holds the URI of the linked entity.

Each nested entity object includes the name of the entity model as well as its properties. In the following example, the entity Person contains the properties name and address. The property name holds a nested entity based on the entity model FullName.

   "instance": {
    ...,
    "Person": {
      "name": {
        "FullName": {
          "title": "Mr.",
          "first": "John",
          "middle": "Doe",
          "last": "Smith"
        }
      },
      "address": "..."
    }
  }