我可以在Android上的多个线程中使用相同的RoomDatabase对象吗？ [英] Can I use the same RoomDatabase object from multiple threads on Android?

问题描述

我在Android上使用Room persistence库。目前，每次访问数据库时都会有一些额外的同步代码。我想知道这段代码是否必要。

I'm using the Room persistence library on Android. Currently, I have some extra synchronization code each time I access the database. I want to know if this code is necessary.

我目前以单身人士的身份访问数据库。
这就是我当前将对象插入数据库的方式：

I currently access the database as a singleton. This is how I am currently inserting objects into the DB:

    // Insert values into DB
    final AppDatabase db = AppDatabase.get(this);
    AsyncTask.execute(new Runnable() {
        @Override
        public void run() {
            synchronized (db) {
                for (WorkOrder wo : workOrderList) {
                    db.workOrderDao().insertAll(wo);
                }
            }
        }
    });

我是否需要在同步块中插入代码？

Do I need to have the insertion code in a synchronized block?

推荐答案

RoomDatabase 包装标准 SQLiteDatabase ，其中是相当线程安全的，所有工作都在交易中完成。

RoomDatabase wraps the standard SQLiteDatabase, which is fairly thread-safe, with all work being done in transactions.

我不会担心 synchronized 等等关于交易，就像现在一样，这项工作是在N个交易中完成的（每个一个WorkOrder ）。我会有一个 insertAll（List< WorkOrder>），因此您可以在一个事务中执行此操作。或者，如果由于某种原因不切实际，请使用 @Transaction @Dao 类中。 c>注释，表示整个方法应在单个事务中执行。

I would worry less about synchronized and more about transactions, as right now, this work is being done in N transactions (one per WorkOrder). I would have an insertAll(List<WorkOrder>), so you can perform this in one transaction. Or, if for whatever reason that's impractical, move your loop into the @Dao class in its own method, with a @Transaction annotation, to indicate that the entire method should be performed in a single transaction.

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