How to update a specific value in a database item? - database

Question

This is a todo list app and uses a database to use the CRUD functions. When the user does a specific action such as tap or swipe i want to mark the task as complete. I am a bit new to databases and am unsure on how to use update item to update the status of a task (completed or not completed).
Could i get a suggestion on what is the correct way to update the _isDone value without deleting a task from the database
Tried to search for other examples of to do list apps but they delete the completed task intead of marking it as completed
database code -
//This is the database
String _itemName;
String _dateCreated;
int _id;
bool _isDone;
TodoItem(this._itemName, this._dateCreated, [this._isDone]);
TodoItem.map(dynamic obj) {
this._itemName = obj["itemName"];
this._dateCreated = obj["dateCreated"];
this._id = obj["id"];
this._isDone = obj["isDone"];
}
String get itemName => _itemName;
String get dateCreated => _dateCreated;
int get id => _id;
bool get isDone => _isDone;
Map<String, dynamic> toMap() {
var map = new Map<String, dynamic>();
map["itemName"] = _itemName;
map["dateCreated"] = _dateCreated;
if (_id != null) {
map["id"] = _id;
}
return map;
}
TodoItem.fromMap(Map<String, dynamic> map) {
this._itemName = map["itemName"];
this._dateCreated = map["dateCreated"];
this._id = map["id"];
this._isDone = map["isDone"];
}
update item function -
Future<int> updateItem(TodoItem item) async {
var dbClient = await db;
return await dbClient.update("$tableName", item.toMap(),
where: "$columnId = ?", whereArgs: [item.id]);
}

Answer 1

please reference this document https://medium.com/flutter-community/using-sqlite-in-flutter-187c1a82e8b
In sqlite example below, update the whole record via a key, "id" here
updateClient(Client newClient) async {
final db = await database;
var res = await db.update("Client", newClient.toMap(),
where: "id = ?", whereArgs: [newClient.id]);
return res;
}
In your example, you update TodoItem and TodoItem include isDone field.
and your syntax is correct
another reference doc https://www.developerlibs.com/2018/07/flutter-sqlite-database-example.html
code snippet of this example
Future<bool> update(User user) async {
var dbClient = await db;
int res = await dbClient.update("User", user.toMap(),
where: "id = ?", whereArgs: <int>[user.id]);
return res > 0 ? true : false;
}
official document about use of sqlite https://flutter.dev/docs/cookbook/persistence/sqlite
code snippet of official document
Future<void> updateDog(Dog dog) async {
// Get a reference to the database.
final db = await database;
// Update the given Dog.
await db.update(
'dogs',
dog.toMap(),
// Ensure that the Dog has a matching id.
where: "id = ?",
// Pass the Dog's id as a whereArg to prevent SQL injection.
whereArgs: [dog.id],
);
}
// Update Fido's age.
await updateDog(Dog(
id: 0,
name: 'Fido',
age: 42,
));
You can build a Database Helper as the example and include your update function
import 'dart:async';
import 'dart:io' as io;
import 'package:flutter_database/database/model/user.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';
class DatabaseHelper {
static final DatabaseHelper _instance = new DatabaseHelper.internal();
factory DatabaseHelper() => _instance;
static Database _db;
Future<Database> get db async {
if (_db != null) return _db;
_db = await initDb();
return _db;
}
DatabaseHelper.internal();
initDb() async {
io.Directory documentsDirectory = await getApplicationDocumentsDirectory();
String path = join(documentsDirectory.path, "main.db");
var theDb = await openDatabase(path, version: 1, onCreate: _onCreate);
return theDb;
}
void _onCreate(Database db, int version) async {
// When creating the db, create the table
await db.execute(
"CREATE TABLE User(id INTEGER PRIMARY KEY, firstname TEXT, lastname TEXT, dob TEXT)");
}
Future<int> saveUser(User user) async {
var dbClient = await db;
int res = await dbClient.insert("User", user.toMap());
return res;
}
Future<List<User>> getUser() async {
var dbClient = await db;
List<Map> list = await dbClient.rawQuery('SELECT * FROM User');
List<User> employees = new List();
for (int i = 0; i < list.length; i++) {
var user =
new User(list[i]["firstname"], list[i]["lastname"], list[i]["dob"]);
user.setUserId(list[i]["id"]);
employees.add(user);
}
print(employees.length);
return employees;
}
Future<int> deleteUsers(User user) async {
var dbClient = await db;
int res =
await dbClient.rawDelete('DELETE FROM User WHERE id = ?', [user.id]);
return res;
}
Future<bool> update(User user) async {
var dbClient = await db;
int res = await dbClient.update("User", user.toMap(),
where: "id = ?", whereArgs: <int>[user.id]);
return res > 0 ? true : false;
}
}