Query Language

Basic selection

query {
  products(limit: 3, order_by: { id: asc }) {
    id
    name
    owner {
      id
      fullName: full_name
    }
  }
}

Primary-key lookup and object shape

query Product($id: ID!) {
  products(id: $id) {
    id
    name
    owner {
      email
    }
  }
}

{ "id": 2 }

Primary-key lookup returns a single object. Collection queries return arrays.

Variables and defaults

query Products($limit: Int = 5) {
  products(limit: $limit, order_by: { id: asc }) {
    id
    name
  }
}

Use variables for values, not for whole query structures. In filters, keep the filter object inline and place variables at leaf values.

Fragments

fragment userFields on users {
  id
  email
}

query {
  users {
    ...userFields
  }
}

Aliases

Aliases are useful when the database column name is not the public field name you want to expose.

query {
  users {
    id
    fullName: full_name
  }
}

Directives

GraphJin supports GraphQL-style conditional fields plus GraphJin-specific add/remove directives for dynamic response shaping.

query ($showProducts: Boolean!) {
  users {
    id
    products @include(if: $showProducts) {
      id
    }
  }
}

GraphJin also supports role and variable variants such as @include(ifRole:), @skip(ifRole:), @include(ifVar:), and @skip(ifVar:), plus relationship directives such as @through(table:) and @through(column:).

Expressions

Expression fields let you compute values from selected columns while staying inside the compiled query path.

query {
  products(where: { id: { lteq: 100 } }) {
    doubled: sum(expr: { mul: [id, 2] })
  }
}

JSON paths and search

query {
  products(limit: 10, order_by: { id: asc }, where: { metadata_foo: { eq: true } }) {
    id
    metadata_foo
  }
}

query SearchProducts($query: String!) {
  products(search: $query, limit: 5) {
    id
    name
  }
}

JSON path shorthand and full-text search are backend-dependent features. Use Database Support when writing portable docs or examples.