异步调用数据库的正确方案：两种仓储实现方式的优选咨询

Great question—you’re spot-on that both approaches are technically valid, but let’s break down why one is the better choice for this scenario.

First, Let’s Recap Your Code #

Calling Method (Unchanged) #

public async Task GetEntry(int id) { 
    var entity = await _repository.GetByIdAsync(id); 
}

Option 1: Repository Without async/await #

public Task<MyEntity> GetByIdAsync(int id) { 
    return Query().SingleOrDefaultAsync(e => e.Id == id); 
}

public IQueryable<MyEntity> Query() { 
    return _dbContext.Set<MyEntity>().AsQueryable(); 
}

Option 2: Repository With async/await #

public async Task<MyEntity> GetByIdAsync(int id) { 
    return await Query().SingleOrDefaultAsync(e => e.Id == id); 
}

public IQueryable<MyEntity> Query() { 
    return _dbContext.Set<MyEntity>().AsQueryable(); 
}

The Preferred Choice: Option 1 #

Here’s why this is the cleaner, more efficient pick:

• No unnecessary state machine overhead: When you use async/await, the compiler generates extra code to track the asynchronous operation’s state (like resuming execution once it’s complete). In Option 1, you’re directly returning the Task that SingleOrDefaultAsync already produces—skipping this overhead entirely while maintaining the same async behavior for callers.
• Identical consumer experience: The calling method uses await regardless, so there’s no difference in how the async flow works from the outside.

When Should You Use Option 2? #

Only add async/await if you need to perform additional work after the database call (before returning the result) or handle exceptions specifically in this method. For example:

public async Task<MyEntity> GetByIdAsync(int id) { 
    try {
        var entity = await Query().SingleOrDefaultAsync(e => e.Id == id);
        // Extra async logic, like logging or mapping
        await _auditLogger.LogFetchAsync(id);
        return entity;
    } catch (DbUpdateException ex) {
        // Wrap or handle the exception before propagating it
        throw new RepositoryException($"Failed to fetch entity {id}", ex);
    }
}

In your original scenario, since there’s no extra logic needed, Option 1 is the optimal approach.

内容的提问来源于stack exchange，提问作者Bumber