3 Types of GraphQL Operations

Use query to get data back

• GraphQL argument is like a filter on particular field.

• Use alias

  • to send same query with different arguments ie available & checkedOut
  • to rename any field

  query {
    available:totalPets(status: AVAILABLE)
    checkedOut:totalPets(status: CHECKEDOUT)
    allPets {
      id
      firstname: name
      weight
      category
    }
  }
  

• Using variables in arguments - use to capture dynamic values/ user inputs

  query ($category:PetCategory $status: PetStatus) {
    allPets(category:$category status:$status) {
      id
      name
      status
      category
    }
  }
  

• Send in variables by using Query Variables panel:

  {
    "cateogry": "DOG",
    "status": "AVAILABLE"
  }
  

• Shortcut Tip: CTRL-space in any graphql playground within context of query to bring up all queries/fileds are available

Use mutation to change data

• convention is to use verbs

mutation {
  vote(host:EVE)
}

Use subscription to listen for data

• listens for data changes in real time over websockets
• open 2 way connection to listen in real time, when mutation comes in, it auto pushes changes to client
• [Subscriptions on Apollo Server]
• [Subscriptions on Apollo Client]

subscription {
  result {
    alex
    eve
  }
}