Step 3: Customize data models

A data model is a conceptual representation of the data structure that will be used under your app. For example, if you are building a blog app, you might have a blog model that represents a blog article. If you are building a social network, you might have a profile model that represents a user profile. Data models should be defined in a GraphQL schema file. For example, we define a post model in post.graphql:

type post @createModel(accountRelation: LIST, description: "post") {
  author: DID! @documentAccount # DID of the user who created this post
  version: CommitID! @documentVersion
  appVersion: String! @string(maxLength: 100)
  text: String @string(maxLength: 300000000) # text content of the post
  images: [String] @list(maxLength: 10000000) @string(maxLength: 2000000) # images of the post
  videos: [String] @list(maxLength: 10000000) @string(maxLength: 2000000) # videos of the post
  options: String @string(maxLength: 300000000)
  createdAt: DateTime! # time when the post is created
  updatedAt: DateTime! # time when the post is updated
}

This represents a post of a web3 social app. A post may contain text, images, and video content.

The @createModel directive is used to tell DataverseOS to create a data model for this type. The @documentAccount directive is used to tell DataverseOS to create a DID for this type. The @documentVersion directive is used to tell DataverseOS to create a version for this type.

profile and post are here to demonstrate how to define a data model. You can define your own data models under the models folder.

For example, if you want to add comments to the post, you can modify the post.graphql like this:

type post @createModel(accountRelation: LIST, description: "post") {
  author: DID! @documentAccount
  version: CommitID! @documentVersion
  appVersion: String! @string(maxLength: 100)
  text: String @string(maxLength: 300000000)
  images: [String] @list(maxLength: 10000000) @string(maxLength: 2000000)
  videos: [String] @list(maxLength: 10000000) @string(maxLength: 2000000)
  options: String @string(maxLength: 300000000)
  createdAt: DateTime!
  updatedAt: DateTime!
  comments: [String] @list(maxLength: 10000000) @string(maxLength: 2000000)
}

Here is another example of a blog model:

type blog @createModel(accountRelation: LIST, description: "post") {
  author: DID! @documentAccount
  version: CommitID! @documentVersion
  title: String @string(maxLength: 100)
  content: String @string(maxLength: 300000000)
  createdAt: DateTime!
  updatedAt: DateTime!
}

author and version are required fields for all data models.author is the DID of the user who created the data. version is used to maintain the update history of the data. These 2 fields will be used by DataverseOS. You should NOT modify them and do NOT need to set them manually when creating a stream.

Data models define the important data types in an application. You can use the data models to create data streams and access the data resources. Creating a data stream under the corresponding model means creating structured data in the application. For example, creating a data stream using the createIndexFile method under the post model means publishing a tweet on a social network.