If you want to return data from multiple tables within a single call, you will need to use the NowGraphQLService() API. If you need to interact with other ServiceNow REST APIs, see Interact with the public REST API on a ServiceNow instance.

Using NowGraphQLService to interact with ServiceNow tables

The NowGraphQLService class provides methods that enable you to construct and execute GraphQL queries on a specified table within your ServiceNow instance if the logged in user has the proper authorization. You can define all CRUD operations within your GraphQL query.

func execute(_ query: GraphQLQuery, completion: @escaping (Result<Data, NowDataError>) → Void)

func execute(_ query: GraphQLQuery) async throws -> Data

func publisher(for query: GraphQlQuery) → AnyPublisher<Data, NowDataError>

// Import the NowData framework
import NowData

// Initialize a NowGraphQLService
// The makeGraphQLService completion handler returns a result that wraps 
// the NowGraphQLService upon success or error. 

private func initializeGraphQLService(instanceUrl: URL) {
  makeGraphQLService(instanceUrl: instanceUrl) { [weak self] result in
    switch result {
    case .success(let service):
      self?.graphQLService = service
    case .failure(let error):
      debugPrint("Creating GraphQL service failed with error: \(error.localizedDescription)")
      self?.graphQLService = nil
    }
  }
}

private func fetchArticles() async throws -> [Article] { 
    guard let graphQLService = graphQLService else { 
        throw ArticleListError.invalidGraphQLService 
    }         

    do {
        let data = try await graphQLService.execute(GraphQLQuery(query: recentlyPublishedQuery))
        let articles = try dataToArticleList(data)
    } catch let error as NowDataError {
        throw ArticleListError.fetchError(error)
    } catch {
        throw error
    }
} 
  
private let recentlyPublishedQuery = 
""" 

{
  GlideRecord_Query {
    kb_knowledge(queryConditions: "active=true^ORDERBYpublishedDESC" pagination: { limit: 10, offset: 0 }) {
      _results { 
        sys_id {
          value
        },
        number {
          displayValue
        },
        short_description {
          displayValue
        },
        author {
          displayValue
        }
        published {
          displayValue
        }
      }
    }
  }
}
"""

Using NowTableService to interact with ServiceNow tables

The NowTableService class provides methods to perform CRUD operations on the records in tables that reside on your ServiceNow instance. Through this interface you can directly access any of the records within any ServiceNow table for which the logged in user is authorized. NowTableService supports dot-walking for reference fields. For example, if a table contains a reference to the User table, the dot-walked value user.name returns the name of the user.

When returning the requested data, all applicable Access Control Lists (ACLs) are applied to the data, which may result in fewer results than expected, or authorization errors if the authenticated user does not have access rights to the specified table.

Most NowTableService methods provide three implementations for returning results data. One that uses async/await, one that calls a completion handler with a Result enumeration, and one that returns a Combine publisher, which is currently deprecated.

For example, all createRecord() methods insert a constructed record into a specified table, however, the

NowTableService - createRecord(with fields: [FieldName: FieldValue], in tableName: String, writeOptions: FieldWriteOptions, configuration: FieldReadConfiguration, completion: @escaping (Result<Data, NowDataError>)

method calls a completion handler with a Result enumeration (the .success case contains the results as its associated value).

The

method performs an async/await function. While the

NowTableService - createRecord(with fields: [FieldName: FieldValue], in tableName: String, writeOptions: FieldWriteOptions? = nil, configuration: FieldReadConfiguration? = nil)

method returns a Combine publisher, but is currently deprecated.

In addition, NowTableService provides two different implementations of CRUD methods, one that returns raw data, and one that returns Codable models. For example, both the update() and updateRecord() methods update a specified record in a specified table, but the update() methods return a Codable model and the updateRecord() methods return raw data. In some cases, Codable methods might be preferable, as a strongly typed Codable structure provides more flexibility than a collection of raw data fields.

// Import the NowData framework
import NowData

// Initialize a NowTableService
// The makeTableService completion handler returns a result that wraps 
// the NowTableService upon success or error. 

makeTableService(instanceUrl: instanceUrl) { [weak self] result in
  guard let self = self else { return }
  
  switch result {
  case .success(let tableService):
    debugPrint("Successfully created a table service \(tableService)")
    self.tableService = tableService
  case .failure(let error):
    debugPrint("Creating table service failed with error: \(error.localizedDescription)")
  }
}

For additional code examples using the available NowTableService methods, refer to the NowTableService class - iOS API documentation.