CRUD
- Dart course
- Advanced
- Lesson 45/83
- 5 min
Learn CRUD operations with sqflite.
CRUD operations
CRUD stands for four basic database operations: Create, Read, Update, Delete. sqflite offers these via db.insert, db.query, db.update and db.delete.
Example: await db.insert('notes', {'title': 'Merhaba'}); adds a new row. final rows = await db.query('notes'); pulls all rows. Each row comes as a Map<String, dynamic>; rows[0]['title'] gives the first row's title.
Inserting and querying rows
To add a row you call db.insert('table', map). The map binds column names to values; for example {'title': 'Merhaba', 'body': 'İlk notum'}.
To query rows you use db.query('table'). The result is a List<Map<String, dynamic>>. rows[0]['title'] gives the first row's title column. In this lesson we will write a crudDemo function: it inserts a note, queries all notes and prints the first note's title.
Practice Insert and query a note
The code below imports sqflite and main opens a Database. Define crudDemo(Database db): insert a note with db.insert('notes', {'title': 'Merhaba', 'body': 'First note'}), query all notes with db.query('notes') and print the first note's title with print('First note: ${rows[0]['title']}'). main already has print('CRUD: insert + query'); add the crudDemo(db) call.
Starter code
import 'package:sqflite/sqflite.dart';
Future<void> crudDemo(Database db) async {
// insert a note (db.insert) and query all notes (db.query)
// print the first note's title
}
void main() async {
print('CRUD: insert + query');
final db = await openDatabase('notes.db');
await crudDemo(db);
await db.close();
}Sample solution
import 'package:sqflite/sqflite.dart';
Future<void> crudDemo(Database db) async {
await db.insert('notes', {'title': 'Merhaba', 'body': 'First note'});
final rows = await db.query('notes');
print('First note: ${rows[0]["title"]}');
}
void main() async {
print('CRUD: insert + query');
final db = await openDatabase('notes.db');
await crudDemo(db);
await db.close();
}Expected output
CRUD: insert + query First note: Merhaba
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Match the CRUD methods
| Term | Meaning |
|---|---|
db.insert |
Create |
db.query |
Read |
db.update |
Update |
db.delete |
Delete |
2 Which method adds a new row?
- db.insert Correct answer
- db.delete
- db.update
- db.query
Explanation: db.insert adds a new row (Create).
3 The db.insert call
await db.____('notes', {'title': 'Merhaba', 'body': 'First note'});await db.insert('notes', {'title': 'Merhaba', 'body': 'First note'});Explanation: db.insert('notes', {...}) adds a new row.