最近在學(xué)習(xí)flutter中的數(shù)據(jù)庫操作,這篇博客用來記錄學(xué)習(xí)中的一些成果,方便以后查閱.
參考文章:http://www.reibang.com/p/0850c80a373c

安裝庫

  sqflite: ^1.1.0

在pubspec.yaml中配置上面內(nèi)容,在終端輸入

flutter pub get

獲取庫內(nèi)容,在要使用的地方導(dǎo)入庫

import 'package:sqflite/sqflite.dart';

此時,就可以使用該庫了.

創(chuàng)建數(shù)據(jù)庫及建表

String sql_createAccountTable = "create table account_table(id integer primary key, username text not null, password text not null)";
Future<String> _createNewDb(String dbName) async {
    var dbPath = await getDatabasesPath();
    print("DBPath:" + dbPath);

    String path = join(dbPath, dbName);
    if (await new Directory(dirname(path)).exists()) {
      await deleteDatabase(path);
    }else {
      try {
        await new Directory(dirname(path)).create(recursive: true);
      } catch(e) {
        print(e);
      }
    }
    return path;
}
_create() async {
    dbPath = await _createNewDb(dbName);
    Database db = await openDatabase(dbPath);
    await db.execute(sql_createAccountTable);
    await db.close();
    print("創(chuàng)建數(shù)據(jù)庫成功");
}

創(chuàng)建成功后,再寫一個獲取數(shù)據(jù)庫的方法,方便每次對數(shù)據(jù)庫的操作

_open() async {
    if (null == dbPath) {
      var path = await getDatabasesPath();
      dbPath = join(path, dbName);
      print('dbPath:'+dbPath);
    }

    return await openDatabase(dbPath);
}

增/刪/改/查

增

 _add(String username, String password) async {
    Database db = await _open();
    String sql = "insert into account_table(username,password) values('$username', '$password')";
    await db.transaction((txn) async {
      int id = await txn.rawInsert(sql);
    });
    await db.close();
    print('插入數(shù)據(jù)成功');
    _refresh();
}

刪

_delete(Map info) async {
    var id = info["id"];
    Database db = await _open();
    String sql = "DELETE FROM account_table where id = $id";
    await db.rawDelete(sql);
    await db.close();
    print('刪除數(shù)據(jù)成功');
    _refresh();
}

改

_update(int id, String account, String pwd) async {
    Database db = await _open();
    String sql = "Update account_table set password = ?, username = ? where id = ?";
    int count = await db.rawUpdate(sql, [pwd, account, id]);
    await db.close();
    print('更新數(shù)據(jù)成功');
    _refresh();
}

查

//查詢數(shù)據(jù)數(shù)目
_queryNumber() async {
    Database db = await _open();
    int count = Sqflite.firstIntValue(await db.rawQuery("select COUNT(*) from account_table"));
    await db.close();
    print("查詢數(shù)據(jù)成功 $count");
    setState(() {
      _cnt = count;
    });
}

//查詢所有數(shù)據(jù)
Future<List> _query() async {
    Database db = await _open();
    List<Map> list = await db.rawQuery("select * from account_table");
    await db.close();
    print(list);
    return list;
}

批量操作

_batch() async {
    Database db = await _open();
    var batch = db.batch();
    batch.insert("account_table", {"username":"123450002", "password":"111"});
    batch.update("account_table", {"username":"123450003"}, where: "username=?", whereArgs: ["123450002"]);
    batch.delete("account_table", where: "username=?", whereArgs: ["123450001"]);
    var results = await batch.commit();
    await db.close();
    print('批量修改成功');
    _refresh();
}

總結(jié)

至此,flutter中數(shù)據(jù)庫的基本操作都已經(jīng)嘗試完畢.記住每步操作都要加上await關(guān)鍵字.
完整Demo地址