Flutter local database sqflite

One 、 Preface

sqflite Is a lightweight database , The usage is similar to SQLite.

Support at the same time Android and iOS

Two 、 quote

sqflite

edition ：^2.0.0+4

function ： Operation of database .

Address ：https://pub.dev/packages/sqflite

3、 ... and 、 Use

Use singleton mode to operate .

Adding, deleting and modifying all contain transactions .

1. Model

final _version = 1;// Database version number 
final _databaseName = "User.db";// Database name 
final _tableName = "user_user";// The name of the table 
final _tableId = "id";// Primary key 
final _tableTitle = "name";// name 
final _tableNum = "num";// size 

2. Database handle

late Database _database;
Future<Database> get database async {
  String path = await getDatabasesPath() + "/$_databaseName";
  _database = await openDatabase(path, version: _version,
                                 onConfigure: (Database db){
                                   print(" Before database creation 、 Before degradation 、 Call before upgrading ");
                                 },
                                 onDowngrade: (Database db, int version, int x){
                                   print(" Call when demoting ");
                                 },
                                 onUpgrade: (Database db, int version, int x){
                                   print(" Call when upgrading ");
                                 },
                                 onCreate: (Database db, int version) async {
                                   print(" Call... On creation ");
                                 },
                                 onOpen: (Database db) async {
                                   print(" Called when reopening ");
                                   await _createTable(db, '''create table if not exists $_tableName ($_tableId integer primary key,$_tableTitle text,$_tableNum INTEGER)''');
                                 },
                                );
  return _database;
}

3. Create table

Future<void> _createTable(Database db, String sql) async{
  var batch = db.batch();
  batch.execute(sql);
  await batch.commit();
}

4. Turn on or off

// open 
Future<Database> open() async{
  return await database;
}

/// close 
Future<void> close() async {
  var db = await database;
  return db.close();
}

5. Add data

static Future insertData(String title, int num) async{
  Database db = await SqfLiteQueueData.internal().open();
  //1、 Ordinary addition 
  //await db.rawDelete("insert or replace into $_tableName ($_tableId,$_tableTitle,$_tableNum) values (null,?,?)",[title, num]);
  //2、 Transaction add 
  db.transaction((txn) async{
    await txn.rawInsert("insert or replace into $_tableName ($_tableId,$_tableTitle,$_tableNum) values (null,?,?)",[title, num]);
  });
  await db.batch().commit();

  await SqfLiteQueueData.internal().close();
}

6. according to id Delete this record

static Future deleteData(int id) async{
  Database db = await SqfLiteQueueData.internal().open();
  //1、 General deletion 
  //await db.rawDelete("delete from _tableName where _tableId = ?",[id]);
  //2、 Transaction deletion 
  db.transaction((txn) async{
    txn.rawDelete("delete from $_tableName where $_tableId = ?",[id]);
  });
  await db.batch().commit();

  await SqfLiteQueueData.internal().close();
}

7. according to id Update this record

static Future updateData(int id,String title, int num) async{
  Database db = await SqfLiteQueueData.internal().open();
  //1、 General update 
  // await db.rawUpdate("update $_tableName set $_tableTitle =  ?,$_tableNum =  ? where $_tableId = ?",[title,num,id]);
  //2、 Transaction update 
  db.transaction((txn) async{
    txn.rawUpdate("update $_tableName set $_tableTitle =  ?,$_tableNum =  ? where $_tableId = ?",[title,num,id]);
  });
  await db.batch().commit();

  await SqfLiteQueueData.internal().close();
}

8. Query all the data

static Future<List<Map<String, dynamic>>> searchDates() async {
  Database db = await SqfLiteQueueData.internal().open();
  List<Map<String, dynamic>> maps = await db.rawQuery("select * from $_tableName");
  print(maps);

  await SqfLiteQueueData.internal().close();
  return maps;
}

9. Delete database tables

static Future<void> deleteDataTable() async {
  Database db = await SqfLiteQueueData.internal().open();
  //1、 General deletion 
  //await db.rawDelete("drop table $_tableName");
  //2、 Transaction deletion 
  db.transaction((txn) async{
    txn.rawDelete("drop table $_tableName");
  });
  await db.batch().commit();

  await SqfLiteQueueData.internal().close();
}

10. Delete database file

static Future<void> deleteDataBaseFile() async {
  await SqfLiteQueueData.internal().close();
  String path = await getDatabasesPath() + "/$_databaseName";
  File file = new File(path);
  if(await file.exists()){
    file.delete();
  }
}

Four 、 Complete code

// ignore_for_file: camel_case_types

import 'dart:io';

import 'package:sqflite/sqflite.dart';

final _version = 1;// Database version number 
final _databaseName = "User.db";// Database name 
final _tableName = "user_user";// The name of the table 
final _tableId = "id";// Primary key 
final _tableTitle = "name";// name 
final _tableNum = "num";// size 

class SqfLiteQueueData{

  SqfLiteQueueData.internal();

  // Database handle 
  late Database _database;
  Future<Database> get database async {
    String path = await getDatabasesPath() + "/$_databaseName";
    _database = await openDatabase(path, version: _version,
      onConfigure: (Database db){
        print(" Before database creation 、 Before degradation 、 Call before upgrading ");
      },
      onDowngrade: (Database db, int version, int x){
        print(" Call when demoting ");
      },
      onUpgrade: (Database db, int version, int x){
        print(" Call when upgrading ");
      },
      onCreate: (Database db, int version) async {
        print(" Call... On creation ");
      },
      onOpen: (Database db) async {
        print(" Called when reopening ");
        await _createTable(db, '''create table if not exists $_tableName ($_tableId integer primary key,$_tableTitle text,$_tableNum INTEGER)''');
      },
    );
    return _database;
  }

  ///  Create table 
  Future<void> _createTable(Database db, String sql) async{
    var batch = db.batch();
    batch.execute(sql);
    await batch.commit();
  }

  ///  Add data 
  static Future insertData(String title, int num) async{
    Database db = await SqfLiteQueueData.internal().open();
    //1、 Ordinary addition 
    //await db.rawDelete("insert or replace into $_tableName ($_tableId,$_tableTitle,$_tableNum) values (null,?,?)",[title, num]);
    //2、 Transaction add 
    db.transaction((txn) async{
      await txn.rawInsert("insert or replace into $_tableName ($_tableId,$_tableTitle,$_tableNum) values (null,?,?)",[title, num]);
    });
    await db.batch().commit();

    await SqfLiteQueueData.internal().close();
  }

  ///  according to id Delete this record 
  static Future deleteData(int id) async{
    Database db = await SqfLiteQueueData.internal().open();
    //1、 General deletion 
    //await db.rawDelete("delete from _tableName where _tableId = ?",[id]);
    //2、 Transaction deletion 
    db.transaction((txn) async{
      txn.rawDelete("delete from $_tableName where $_tableId = ?",[id]);
    });
    await db.batch().commit();

    await SqfLiteQueueData.internal().close();
  }

  ///  according to id Update this record 
  static Future updateData(int id,String title, int num) async{
    Database db = await SqfLiteQueueData.internal().open();
    //1、 General update 
    // await db.rawUpdate("update $_tableName set $_tableTitle =  ?,$_tableNum =  ? where $_tableId = ?",[title,num,id]);
    //2、 Transaction update 
    db.transaction((txn) async{
      txn.rawUpdate("update $_tableName set $_tableTitle =  ?,$_tableNum =  ? where $_tableId = ?",[title,num,id]);
    });
    await db.batch().commit();

    await SqfLiteQueueData.internal().close();
  }

  ///  Query all the data 
  static Future<List<Map<String, dynamic>>> searchDates() async {
    Database db = await SqfLiteQueueData.internal().open();
    List<Map<String, dynamic>> maps = await db.rawQuery("select * from $_tableName");
    print(maps);

    await SqfLiteQueueData.internal().close();
    return maps;
  }

  // open 
  Future<Database> open() async{
    return await database;
  }

  /// close 
  Future<void> close() async {
    var db = await database;
    return db.close();
  }

  /// Delete database tables 
  static Future<void> deleteDataTable() async {
    Database db = await SqfLiteQueueData.internal().open();
    //1、 General deletion 
    //await db.rawDelete("drop table $_tableName");
    //2、 Transaction deletion 
    db.transaction((txn) async{
      txn.rawDelete("drop table $_tableName");
    });
    await db.batch().commit();

    await SqfLiteQueueData.internal().close();
  }

  /// Delete database file 
  static Future<void> deleteDataBaseFile() async {
    await SqfLiteQueueData.internal().close();
    String path = await getDatabasesPath() + "/$_databaseName";
    File file = new File(path);
    if(await file.exists()){
      file.delete();
    }
  }
}