The final variable of TableData, how to use the portable setter

[greenking19]

👇 Example

TaskTableData _taskData = await appDatabase.select(appDatabase.taskTable).getSingle();
 ///  change property
 ///  error: Try finding a different setter, or making 'taskId' non-final.
 _taskData.taskId = 'test';

 /// Insert/Upgrade Table
await appDatabase.into(appDatabase.taskTable).insertOnConflictUpdate(_taskData);

This is wrong, are there other alternatives?
Now I use TableData.toJson and TableData.formJson, then insertOnConflictUpdate

---

I also encountered a small problem when developing
If there is no such data in the table, it will prompt a null error

TaskTableData _list = await (appDatabase.select(appDatabase.taskTable)
          ..where((tbl) => tbl.taskId.equals(taskId)))
        .getSingle();

But if I write, editor prompt always true

In the end, I wrote it like this.

[greenking19]

🤯 Damn, I forgot to have TableCompanion.
🤯 Sorry I made this basic mistake.

---

Currently I only have this problem with getSingle.
When the table doesn't have the data I want it throws a null error

[simolus3]

This is wrong, are there other alternatives?

You could instruct drift to generate mutable data classes with the mutable_classes build option. But that's a pretty major switch and recommend keeping them immutable, as that's the way most drift APIs were designed.

I'd just use _taskData = _taskData.copyWith(taskId: 'test') in this case (the same works for companions).

Currently I only have this problem with getSingle.

Just use getSingleOrNull(), it's exactly what you need here! getSingle is written under the assumption that you're going to have at least one row.

[greenking19]

Thank you for clearing my doubts.
😋

[greenking19]

I want to use TableData in the modified form. It needs to be populated during initialization.
But I found that toJson is not what I expected

class TestTable extends Table{
  TextColumn get id => text().named('ID')();
  TextColumn get message text().named('Message')();
  @override
  Set<Column> get primaryKey => {id};
}

this my conversion class

class TestConvert {
  String? iD;
  String? message;

  TestConvert({this.iD, this.message});

  TestConvert.fromJson(Map<String, dynamic> json) {
    iD = json['ID'];
    message = json['Message'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['ID'] = this.iD;
    data['Message'] = this.message;
    return data;
  }
}

my expectations.
Query out the old data, and then fill it into ConvertClass. Then hand it over to the form to Change
then save

// A testTableData that was queried
TestTableData testTable = xxx.get();

TestConvert formData = TestConvert.formJson(testTable.toJson());

But I found that the generated TableData.toJson is like this.
I have a lot of forms. They are all for inserting into the database. TableData cannot be used directly.
Currently I can only modify my ConvertClass. Is there any other solution?

 Map<String, dynamic> toJson({ValueSerializer? serializer}) {
    serializer ??= driftRuntimeOptions.defaultSerializer;
    return <String, dynamic>{
      'id': serializer.toJson<String>(id),
      'message': serializer.toJson<String>(message),
   );
}

[simolus3]

named only affects the name of the column in SQL. You need to add a @JsonKey annotation onto the column to change the JSON key.

But if your intention is to go from drift data classes from and to your form data classes, it's much easier to just make drift use your form classes directly! You can do this with custom data classes:

@UseRowClass(TestConvert)
class TestTable extends Table{
  TextColumn get id => text()();
  TextColumn get message text()();
  @override
  Set<Column> get primaryKey => {id};
}

[greenking19]

Thank you now the problem is solved. This is my problem, I don't have the documentation.
thanks for your help