Waiting dabatabase loading

Hi everyone. I'm a newbye, so, sorry if I'm asking something obvious.
I have to do load and update a database with C#.

The plan is to do the following:

1) Load the database
2) Wait until it finishes loading
3) Update the database

Alas seems I've a few problems with coroutines.

I tried this:

IEnumerator WaitDatabase (bool busy)
{
while (busy)
{
yield return null;
}
}

public IEnumerator LoadDatabase()
{
//Load the database
busy = false;
}

public void UpdateDatabase()
{
//update database
}

void Update
{
LoadDatabase();
WaitDatabase();
UpdateDatabase();
}

I'm still learning co routines and I think I really could use a hand.