Entities

In ElectroDB an Entity represents a single business object. For example, in a simple task tracking application, one Entity could represent an Employee and or a Task that is assigned to an employee.

ElectroDB was created with Single-Table Design in mind. As a result, entities created by ElectroDB will automatically be isolated from entities created by ElectroDB. In turn, this means a single dynamodb table is capable of containing an infinite number of ElectroDB entities.

Creation

Entities are defined via a Schema, passed to the Entity’s constructor.

import DynamoDB from "aws-sdk/clients/dynamodb";
import { Entity } from "electrodb";

const client = new DynamoDB.DocumentClient();

const table = "electro";

const Task = new Entity(
  {
    model: {
      entity: "task",
      version: "1",
      service: "taskapp",
    },
    attributes: {
      task: {
        type: "string",
        default: () => uuid(),
      },
      project: {
        type: "string",
      },
      employee: {
        type: "string",
      },
      description: {
        type: "string",
      },
    },
    indexes: {
      task: {
        pk: {
          field: "pk",
          composite: ["task"],
        },
        sk: {
          field: "sk",
          composite: ["project", "employee"],
        },
      },
      project: {
        index: "gsi1pk-gsi1sk-index",
        pk: {
          field: "gsi1pk",
          composite: ["project"],
        },
        sk: {
          field: "gsi1sk",
          composite: ["employee", "task"],
        },
      },
      assigned: {
        collection: "assignments",
        index: "gsi3pk-gsi3sk-index",
        pk: {
          field: "gsi3pk",
          composite: ["employee"],
        },
        sk: {
          field: "gsi3sk",
          composite: ["project", "task"],
        },
      },
    },
  },
  { table, client },
);

Additionally, as a second parameter to the constructor, ElectroDB accepts an “options” object that defines the electrodb TableName and a DynamoDB DocumentClient.

Entity Definition (Schema)

Entity Options