final Database database = await openDatabaseConnection(); await deleteAllRows(database); await database.close(); } Future<Database> openDatabaseConnection() async { final directory = await getApplicationDocumentsDirectory(); final path = join(directory.path, 'your_database.db'); return await...
void insertData(Database db, String name, String value) async { await db.insert('myTable', {'name': name, 'value': value}); } 查询数据 Future<List<Map<String, dynamic>>> fetchData(Database db) async { return await db.query('myTable'); } 云端数据存储 云端数据存储允许应用将数据在...
1回答 Microsoft.EntityFrameworkCore.Database.Connection在暂存服务器中使用到数据库的连接发生错误 、、 我在连接API到Server的服务器上有问题。我的环境是.NET 6,我使用这个应用程序来执行API。当我运行API时,我会得到一个HTTP 500内部服务器错误。事件查看器中的消息错误为Microsoft.EntityFrameworkCore.D...
AppDatabase() : super(_openConnection()); @override int get schemaVersion => 1; //插入一条数据 Future<int> saveEmployee(EmployeeData companion) async { return await into(employee).insert(companion); } } LazyDatabase _openConnection() { return LazyDatabase(() async { final dbFolder = a...
Database db = await this.database; var result = await db.insert(noteTable, note.toMap()); return result; } 但是postgre库没有提供这些,需要自己做一点封装。 下面是我封装的方法,方便插入和更新数据。 static String getInsertSql(String table, Map<String, dynamic> values, ...
Future Database() async { var settings = mysql.ConnectionSettings( host: '108...', port: 3306, user: 'root', password: '***', useSSL: false, useCompression: false, // maxPacketSize: 10000000, //characterSet: utf8, timeout: const Duration(seconds: 5000), db: 'testdb'); var ...
Database db = await this.database; var result = await db.insert(noteTable, note.toMap()); return result; } 1. 2. 3. 4. 5. 但是postgre库没有提供这些,需要自己做一点封装。 下面是我封装的方法,方便插入和更新数据。 static String getInsertSql(String table, Map<String, dynamic> values, ...
Future doQuery() async{ // Open a connection (testdb should already exist) final conn = await MySqlConnection.connect(ConnectionSettings( host: 'localhost', port: 3306, user: 'root', db: 'sakila', password: '123456')); // Query the database using a parameterized query //SELECT first_...
For accessing and working with the database, create a singletonDatabaseHelperclass. A singleton class will ensure that we only have one instance of the database connection and global access to the database that can be called from anywhere in the project. ...
[logging]APIcall with invalid database connection pointer[logging]misuse at line134561of[9ff244ce07][WCDB][DEBUG]Code:21,Type:SQLiteGlobal,Msg:library routine calledoutof sequenceDBError:21"library routine called out of sequence"DBQuery:SELECTtbl_nameFROMsqlite_masterWHEREtype='table'ANDtbl_name=?