function updateFunction(executionContext) {
var formContext = executionContext.getFormContext()
var abcVariable= formContext.getAttribute("fieldABCTable").getValue();
var recordId = formContext.data.entity.getId();
if (abcVariable!== null) {
recordId = recordId.replace(/[{}]/g, "");
Xrm.WebApi.retrieveMultipleRecords(Xrm.WebApi.retrieveMultipleRecords("entitys", recordId, "?$select=fieldOnOtherTable").then(
function success(result) {
for (var i = 0; i < result.entities.length; i++) {
console.log(result.entities[i]);
formContext.getAttribute(result.entities[i]).setValue(abcVariable)
}
},
function (error) {
console.log(error.message);
// handle error conditions
}
);
}
}