使用Kotlin在SQLite中查询时出现问题

import android.content.Context
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper

class DatabaseHelper(context: Context) : SQLiteOpenHelper(context, DATABASE_NAME, null, DATABASE_VERSION) {
    companion object {
        const val DATABASE_NAME = "mydatabase.db"
        const val DATABASE_VERSION = 1
    }

    override fun onCreate(db: SQLiteDatabase) {
        // 创建表的SQL语句
        db.execSQL("CREATE TABLE mytable (id INTEGER PRIMARY KEY, name TEXT)")
    }

    override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
        // 升级数据库时的操作
        db.execSQL("DROP TABLE IF EXISTS mytable")
        onCreate(db)
    }
}

val dbHelper = DatabaseHelper(context)
val db = dbHelper.readableDatabase

val query = "SELECT * FROM mytable WHERE id = ?"
val cursor = db.rawQuery(query, arrayOf(id.toString()))

if (cursor.moveToFirst()) {
    do {
        val name = cursor.getString(cursor.getColumnIndex("name"))
        // 处理查询结果
    } while (cursor.moveToNext())
}

cursor.close()
db.close()

db.execSQL("CREATE INDEX idx_name ON mytable(name)")

db.beginTransaction()
try {
    // 执行数据库操作
    db.setTransactionSuccessful()
} finally {
    db.endTransaction()
}