silverstripe-framework/docs/en/02_Developer_Guides/19_GraphQL/02_working_with_dataobjects/06_property_mapping.md
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---
title: Property mapping and dot syntax
summary: Learn how to customise field names, use dot syntax, and use aggregate functions
---
# Working with DataObjects
[CHILDREN asList]
[alert]
You are viewing docs for a pre-release version of silverstripe/graphql (4.x).
Help us improve it by joining #graphql on the [Community Slack](https://www.silverstripe.org/blog/community-slack-channel/),
and report any issues at [github.com/silverstripe/silverstripe-graphql](https://github.com/silverstripe/silverstripe-graphql).
Docs for the current stable version (3.x) can be found
[here](https://github.com/silverstripe/silverstripe-graphql/tree/3)
[/alert]
## 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:
*app/_graphql/models.yml*
```yaml
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*
```yaml
MyProject\Pages\Blog:
fields:
title: true
authorName:
type: String
property: 'Author.FirstName'
```
Fields on plural relationships will automatically convert to a `column` array:
*app/_graphql/models.yml*
```yaml
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*
```yaml
MyProject\Models\ProductCategory:
fields:
title: true
productCount:
type: Int
property: 'Products.Count()'
averageProductPrice:
type: Float
property: 'Products.Avg(Price)'
```
### Further reading
[CHILDREN]