DatabaseException（数据库已锁定（代码5）：，而编译时：PRAGMA journal_mode）

Question

使用[var db = await openDatabase（）function]打开基础时：PlatformException (PlatformException(sqlite_error, Cannot perform this operation because there is no current transaction., {arguments: [], sql: null}))。因此，我想问一下如何在事务中传递此函数，我还要注意，尽管我每次都继续执行onCreate的功能，但继续执行时。

并继续执行，一切顺利，在发行版中我遇到此错误： DatabaseException(database is locked (code 5): , while compiling: PRAGMA journal_mode)

这是ma代码：

import 'dart:io';
import 'package:ecom_app/models/favorites.dart';
import 'package:ecom_app/models/user_local.dart';
import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';

class DBhelper {
static final DBhelper _instance = new DBhelper.internal();
factory DBhelper() => _instance;
static Database _db;
DBhelper.internal();

final String tableUser = 'users';
final String columnId = 'id';
final String columnFId = 'fid';
final String columnFUserId = 'fuserid';
final String columnfullname = 'fullname';
final String columnnumber = 'number';
final String columnimgurl = 'imgurl';
final String columnimglocal = 'imglocal';
final String columnrole = 'role';
final String columntoken = 'token';

final String table1 = 'favorites';
final String column1Id = 'id';
final String column1ItemId = 'itemId';
final String column1Name = 'name';
final String column1Lat = 'lat';
final String column1Long = 'long';
final String column1Desc = 'desc';

dynamic initScript = [];

static FavoritesMarkerItem _fromMap(Map<dynamic, dynamic> data) => new FavoritesMarkerItem.fromMap(data);

Future<Database> get db async {
    initScript.addAll([
        'CREATE TABLE $tableUser($columnId INTEGER PRIMARY KEY, $columnFId TEXT, $columnFUserId TEXT, $columnfullname TEXT, $columnnumber TEXT, $columnimgurl TEXT, $columnimglocal TEXT, $columnrole TEXT, $columntoken TEXT)',
        'CREATE TABLE $table1($column1Id INTEGER PRIMARY KEY, $column1ItemId TEXT, $column1Name TEXT, $column1Lat REAL NOT NULL, $column1Long REAL NOT NULL)',
    ]);

    if (_db != null)
        return _db;

    _db = await initDb();
    return _db;
}

Future<Database> initDb() async {
    String databasesPath = await getDatabasesPath();
    String path = join(databasesPath, 'gbameh.db');

    Database db = await openDatabase(path,
        version: 2,
        onCreate: _onCreate,
        onUpgrade: _onUpgrade,
    );
    return db;
}

_onCreate(Database db, int newVersion) async {
    await db.transaction((trx) async{
        initScript.forEach((script) async=> await trx.execute(script));
    });
}

_onUpgrade(Database db, int oldVersion, int newVersion) async {
    initScript = [
        'ALTER TABLE $table1 ADD COLUMN $column1Desc TEXT',
    ];
    await db.transaction((trx) async{
        initScript.forEach((script) async=> await trx.execute(script));
    });
}

Future<int> saveUser(UserLocal user) async {
    var dbClient = await db;
    var res = await dbClient.insert(tableUser, user.toMap(), conflictAlgorithm: ConflictAlgorithm.replace);
    return res;
}

Future<UserLocal> getUser() async {
    var dbClient = await db;
    List<Map> res = await dbClient.query(tableUser,
        columns: [columnId, columnFId, columnFUserId, columnfullname, columnnumber, columnimgurl, columnimglocal, columnrole, columntoken],
        where: '$columnId = ?',
        whereArgs: [1]
    );
    if (res.length > 0) {
        return new UserLocal.fromMap(res.first);
    }
    return null;
}

Future<int> update(UserLocal user) async {
    var dbClient = await db;
    return await dbClient.update(tableUser, user.toMap(), where: "$columnId = ?", whereArgs: [1]);
}

Future<int> deleteUser() async {
    var dbClient = await db;
    return await dbClient.delete(tableUser);
}

// Favorite

Future<int> save(FavoritesItem item) async {
    var dbClient = await db;
    var res = await dbClient.insert(table1, item.toMap());
    return res;
}

Future<List<FavoritesItem>> getAll() async {
    var dbClient = await db;
    List<Map> res = await dbClient.query(
        table1,
        columns: [column1Id, column1ItemId, column1Name, column1Lat, column1Long, column1Desc],
        orderBy: column1Id
    );
    return res.length > 0 ? res.map(_fromMap).toList() : null;
}

Future<List<FavoritesItem>> getItem(String id) async {
    var dbClient = await db;
    List<Map> res = await dbClient.query(
        table1,
        columns: [column1Id, column1ItemId, column1Name, column1Lat, column1Long, column1Desc],
        where: '$column1ItemId = ?',
        whereArgs: [id],
    );
    return res.length > 0 ? res.map(_fromMap).toList() : null;
}

Future close() async {
    var dbClient = await db;
    return dbClient?.close();
}
}

DBhelper dbHelper = new DBhelper();