silverstripe-framework/docs/en/02_Developer_Guides/19_GraphQL/02_working_with_dataobjects/06_property_mapping.md

title	summary
Property mapping and dot syntax	Learn how to customise field names, use dot syntax, and use aggregate functions

Working with DataObjects

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[info] You are viewing docs for silverstripe/graphql 4.x. If you are using 3.x, documentation can be found in the github repository [/info]

Property mapping and dot syntax

For the most part, field names are inferred through the DataObject model, but its API affords developers full control over naming.

In this example, we are taking a property content (which will be defined as Content in php) and defining it as pageContent for GraphQL queries and mutations.

app/_graphql/models.yml

Page:
  fields:
    pageContent:
      type: String
      property: Content

[notice] When using explicit property mapping, you must also define an explicit type, as it can no longer be inferred. [/notice]

Dot-separated accessors

Property mapping is particularly useful when using dot syntax to access fields.

app/_graphql/models.yml

MyProject\Pages\Blog:
  fields:
    title: true
    authorName:
      type: String
      property: 'Author.FirstName'

Fields on has_many or many_many relationships will automatically convert to a column array:

app/_graphql/models.yml

MyProject\Pages\Blog:
  fields:
    title: true
    categoryTitles:
      type: '[String]'
      property: 'Categories.Title'
    authorsFavourites:
      type: '[String]'
      property: 'Author.FavouritePosts.Title'

We can even use a small subset of aggregates, including Count(), Max(), Min() and Avg().

app/_graphql/models.yml

MyProject\Models\ProductCategory:
  fields:
    title: true
    productCount:
      type: Int
      property: 'Products.Count()'
    averageProductPrice:
      type: Float
      property: 'Products.Avg(Price)'

Further reading

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