FD1 Get Attribute

The get Attribute group of functions allow you to retrieve a single value (attribute) for a single item.

SQL users: Get Attribute is similar to a multi table join selecting one field for a single record.

OO users: Get Attribute traverses objects to connected objects and can return any single property

Their power is that you can also navigate to related data and return an attribute from there. This makes them incredibly useful for web pages that might sometimes need an additional specific fact about a single product/customer/sale/etc Some examples to explain

fd1.products.get_product_attribute(description)

fd1.products.get_product_attribute(barcode)

fd1.products.get_product_attribute(barcode[0])
fd1.products.get_product_attribute(barcode[1])
fd1.products.get_product_attribute(barcode[2])

fd1.products.get_product_attribute(barcode[1].physkey)

You can get quite deep with path traversal, as shown below (this is a conceptual example, it will not work)

fd1.products.get_product_attribute(last_sale[store=york].customer.email)

products.get_product_attribute(want-string)

Want-String Format

Want strings have the generic format:

attribute[selector].attribute[selector]...{converter}/format-mask

attribute is the name of the attribute (property/field) required. Essentially this is the name of the field where the data is stored

selector is an optional restriction where the attribute can have multiple values. If not provided, the first value is returned. "first" in this context varies by where/what resource is being used.

Where the requested attribute redirects to a related resource (eg sale -> customer), then you may repeat the process and request a specific attribute of that resource (eg a "customer" attribute). If you redirect to a related resource and do not provide an attribute, a default attribute will be provided.

Optional converters can be invoked to reprocess the value in someway. This is not currently implemented and reserved for future expansion

The final component is an optional format-mask, which requests the server to reformat the final return value in some way. A format-mask starts with a slash ( / ) followed by the mask definition. For example pretty printing, reformatting to various standards. Basically this saves clients from needing to format values. When a format mask is used, the output is typically a string so as to preserve formatting.

Consider fd1.sales.get_sale_attribute() as the initial call.
We are starting from a single "sale" resource, which is identified by the "k" query parameter

{
    a: "fd1.sales.get_sale_attribute(want-string)",
    k: 8451325
}
                

{
  "rp": "27",
  "data": {
    "rows": [
      "23-may-2021 15:54"
    ]
  }
}

{
  "rp": "27",
  "data": {
    "rows": [
      14.92
    ]
  }
}

{
  "rp": "27",
  "data": {
    "rows": [
      "14.9200"
    ]
  }
}

{
  "rp": "27",
  "data": {
    "rows": [
      "John Smith"
    ]
  }
}

{
  "rp": "27",
  "data": {
    "rows": [
      true
    ]
  }
}