18. A non-transitory computer-readable medium embodying program code for an application development tool, the program code comprising: program code for receiving an input modifying source code of an application, the source code providing one or more elements of the application when executed at runtime; program code for determining that the input specifies a data interaction element, the data interaction element referencing an interaction by the application with a data source at runtime; and program code for, responsive to determining that the input specifies the data interaction element: querying the data source and receiving a returned data sample comprising one or more data parameters in response to the query, wherein the one or more data parameters are communicated between the application and the data source at runtime to access data associated with the one or more data parameters; characterizing the data of the returned data sample, wherein characterizing the data comprises determining, from the returned data sample, a data structure definition for the returned data sample and a source code element for referring to the one or more data parameters; and providing output comprising a suggested type characterization for the data returned by the interaction, wherein the suggested type characterization comprises at least one of (i) one or more options for completing an incomplete reference in the source code to the one or more data parameters and (ii) a suggested syntax of a source code segment referencing the one or more data parameters.
18. A non-transitory computer-readable medium embodying program code for an application development tool, the program code comprising: program code for receiving an input modifying source code of an application, the source code providing one or more elements of the application when executed at runtime; program code for determining that the input specifies a data interaction element, the data interaction element referencing an interaction by the application with a data source at runtime; and program code for, responsive to determining that the input specifies the data interaction element: querying the data source and receiving a returned data sample comprising one or more data parameters in response to the query, wherein the one or more data parameters are communicated between the application and the data source at runtime to access data associated with the one or more data parameters; characterizing the data of the returned data sample, wherein characterizing the data comprises determining, from the returned data sample, a data structure definition for the returned data sample and a source code element for referring to the one or more data parameters; and providing output comprising a suggested type characterization for the data returned by the interaction, wherein the suggested type characterization comprises at least one of (i) one or more options for completing an incomplete reference in the source code to the one or more data parameters and (ii) a suggested syntax of a source code segment referencing the one or more data parameters. 22. The computer-readable medium set forth in claim 18 , wherein characterizing the data is based on an additional input specifying a custom type characterization for use in referring to the source code element.