{ "type":"object",
  "title": "line item",
  "description": "A line item for a document",
  "properties":{
    "id":{
      "description": "uuid of the item.",
      "identity":true,
      "readonly":true,
      "type":"string"
    },
    "position":{
      "description": "Required since items are sorted by position.",
      "type":"integer"
    },
    "name":{
      "description": "The name of an item",
      "optional":true,
      "type":"string"
    },
    "description":{
      "description": "Item description",
      "optional":true,
      "type":"string"
    },
    "price_single":{
      "description": "Net price of a single item",
      "type":"number"
    },
    "tax":{
      "description": "Tax percent for a single item.",
      "optional":true,
      "type":"number"
    },
    "discount":{
      "description": "Discount in percent applied to the items net total",
      "optional":true,
      "type":"number"
    },
    "quantity_unit":{
      "description": "Unit like kg, days, month.",
      "optional":true,
      "type":"string"
    },
    "quantity":{
      "description": "Quantity of the item.",
      "type":"number"
    },
    "product_id":{
      "description": "An item can reference a product by its uuid. See use_product",
      "optional":true,
      "type":"string"
    },
    "use_product":{
      "description": "If set and product_id is present, the products name, description, quantity, unit, price are copied if the according item fields are missing.",
      "optional":true,
      "type":"integer"
    },
    "created_at":{
      "description": "Date the object was created in SK. Never changes aftwerwards",
      "format":"date-time",
      "optional":true,
      "readonly":true,
      "type":"string"
    },
    "updated_at":{
      "description": "Date the object was edited in SK.",
      "format":"date-time",
      "optional":true,
      "readonly":true,
      "type":"string"
    }
  }
}