How can I save two records with the id of the other in flutter?

I'm trying to save two records with id of the other, I can do that, but when I try to save more than 2 at same time some id come with blank. This is my code:

collectionReferenceRel.add({
  'idRoom': id,
  'room': rel,
  'rel': room,
  'id': '',
}).then((idRel) {
   idRel1 = idRel.id;
 },
);
collectionReferenceRel.add({
  'idRoom': id,
  'room': room,
  'rel': rel,
  'id': '',
}).then((value2) {
  idNode2 = value2.id;
}).whenComplete(() async {
  await collectionReferenceRel.doc(idRel1).update({
  'id': idRel2,
 });
 await collectionReferenceRel.doc(idRel2).update({
 'id': idRel1,
 });
}).catchError((error) {
 CustomFullScreenDialog.cancelDialog();
 CustomSnackBar.showSnackBar(
     context: Get.context,
     title: 'Error',
     message: 'Something went wrong',
     backgroundColor: Colors.green);
 [![enter image description here][1]][1] }, 
 );

CodePudding user response：

https://api.flutter-io.cn/flutter/dart-async/Future/wait.html

Future.wait([
collectionReferenceRel.add({
  'idRoom': id,
  'room': rel,
  'rel': room,
  'id': '',
}).then((idRel) {
   idRel1 = idRel.id;
 },
),
collectionReferenceRel.add({
  'idRoom': id,
  'room': room,
  'rel': rel,
  'id': '',
}).then((value2) {
  idNode2 = value2.id;
})
]).whenComplete(() async {
  await collectionReferenceRel.doc(idRel1).update({
  'id': idRel2,
 });
 await collectionReferenceRel.doc(idRel2).update({
 'id': idRel1,
 });
}).catchError((error) {
 CustomFullScreenDialog.cancelDialog();
 CustomSnackBar.showSnackBar(
     context: Get.context,
     title: 'Error',
     message: 'Something went wrong',
     backgroundColor: Colors.green);
 [![enter image description here][1]][1] }, 
 );

CodePudding user response：

Consider using the set() method provided the cloud firestore api.

Usage Example from the reference.

final city = <String, String>{
  "name": "Los Angeles",
  "state": "CA",
  "country": "USA"
};

db.collection("cities")
  .doc("LA")
  .set(city)
  .onError((e, _) => print("Error writing document: $e"));

For saving more than one document consider coupling it with the Future wait for a clean code.

 /// Create a list to add all documents
 final List docs = [];


 /// create the documents with unique identifiers 
 /// beforehand using a package such as `Uuid`
 final docA = {
  'id': 'unique_identifier_a',
  'idRoom': id,
  'room': rel,
  'rel': room,
 }

 docs.add(docA);

 final docB = {
  'id': 'unique_identifier_b',
  'idRoom': id,
  'room': rel,
  'rel': room,
 }

 docs.add(docB);

/// Create futures from the documents
final futures = docs.map((e) => collectionRef.doc(e.id).set(e));
 

/// Save the documents in shot and wait for all
await Future.wait(futures);