flutter sqlite事务使用错误警告数据库已被锁定 [英] flutter sqlite transaction usage error warning database has been locked for
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问题描述
我正在开发使用sqlite和事务处理的移动应用程序.
I am developing a mobile application that use sqlite and transaction.
下面的代码是通过使用sqlite事务保存模型从用户那里获取订单信息到多个数据库表.
Below code is that getting order information from user using by using sqlite transaction saving model to multiple db tables.
Future<AppResult<int>> save(Order order) async {
Database db;
var dbReturn = BaseService();
try {
db = await databaseOpen();
int dbSaveResult = 0;
await db.transaction((txn) async {
var batch = txn.batch();
final List<Map<String, dynamic>> exist = await db.query(tableName, where: "id =?", whereArgs: [order.id]);
if (exist.length == 0) {
await _insert(order, txn, batch);
} else {
await _update(order, txn, batch);
}
await batch.commit(continueOnError: true).then((value) {
if (value.length > 0) dbSaveResult = value.length;
});
});
return dbReturn.success<int>(dbSaveResult, "Kaydedildi", 1, 1);
} on Exception catch (e) {
return dbReturn.failed<int>(-1, "OrderDbService -> save", 0, 0, e);
} finally {
if (db != null && db.isOpen) {
await db.close();
}
}
}
Future<void> _insert(Order order, Transaction txn, Batch batch) async {
try {
order = setEntityValue(order, false);
order = _setOrder(order, order.lines);
batch.insert(tableName, order.toMap(), conflictAlgorithm: ConflictAlgorithm.replace);
await _saveLines(order.lines, txn, batch);
await _saveDescriptions(order.descriptions, txn, batch);
await _saveDetail(order.detail, txn, batch);
await _saveDiscounts(order.discounts, txn, batch);
await _saveExchangeRates(order.exchangeRates, txn, batch);
} on Exception catch (e) {
throw e;
}
}
在调用sqlite方法后,将引发如下消息
after calling the method sqlite throw a message as below
D/Sqflite ( 8938): [57,main(2)] starting threadThread[Sqflite,5,main] priority 10
D/Sqflite ( 8938): [57,main(2)] opened 57 /data/user/0/com.tttt.mobileApp/databases/tttt.db
D/Sqflite ( 8938): [57,Sqflite(484)] opened 57 /data/user/0/com.tttt.mobileApp/databases/tttt.db
D/Sqflite ( 8938): [57,Sqflite(484)] BEGIN IMMEDIATE
I/flutter ( 8938): Warning database has been locked for 0:00:10.000000. Make sure you always use the transaction object for database operations during a transaction
推荐答案
已解决:确保您不在事务内使用数据库实例
SOLVED: be sure you don't use db instance inside the transaction as below
await db.query(tableName, where: "id =?", whereArgs: [order.id]);
代替下面的用法
await txn.query(tableName, where: "id =?", whereArgs: [order.id]);
flutter不会警告您任何交易使用错误.
flutter does not warn you about any transaction usage error.
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