/// <summary>
/// 根据键值获取所在的数据库
/// </summary>
/// <param name="keyvalue"></param>
/// <returns></returns>
public DbContext GetDbContextByKey(long keyvalue)
{
DbShardingItem dbShardingItem = null;
foreach (var item in ShardingInfos)
{
if (keyvalue >= item.IdMin && keyvalue <= item.IdMax)
{
dbShardingItem = item;
break;
}
}
if (dbShardingItem == null)
{
throw new Exception($" keyvalue '{keyvalue}' out of sharding range");
}
//根据id求模，选出数据库
var index = (int)(keyvalue % (dbShardingItem.Servers.Count()));
var dbserver = dbShardingItem.Servers[index];
DbContext dbContext = GetDbContext(dbserver);
return(dbContext);
}
public async Task <T> FindAsync <T> (long id)
where T : class
{
DbShardingItem dbShardingItem = null;
foreach (var item in ShardingInfos)
{
if (id >= item.IdMin && id <= item.IdMax)
{
dbShardingItem = item;
break;
}
}
if (dbShardingItem == null)
{
throw new Exception($" idvalue '{id}' out of sharding range");
}
//hash模式
if (dbShardingItem.ReadMode == ShardingReadMode.Hash)
{
//根据id求模，选出数据库
var index = (int)(id % (dbShardingItem.Servers.Count()));
var dbserver = dbShardingItem.Servers[index];
DbContext dbContext = GetDbContext(dbserver);
return(await dbContext.FindAsync <T>(id));
}
//完全模式
else
{
List <Task <T> > tasks = new List <Task <T> >();
foreach (var dbserver in dbShardingItem.Servers)
{
DbContext dbContext = GetDbContext(dbserver);
tasks.Add(dbContext.FindAsync <T>(id));
}
var result = await Task.WhenAll(tasks);
return(result.FirstOrDefault());
}
}
public List <DbShardingItem> GetDbShardingItems( )
{
List <DbShardingItem> dbShardingItems = new List <DbShardingItem>();
foreach (var item in this)
{
DbShardingItem dbShardingItem = new DbShardingItem(item.Servers.Select(t => new DbInfo
{
Name = t.Key,
ConnectionString = t.Value
}).ToList());
dbShardingItem.IdMax = item.IdMax;
dbShardingItem.IdMin = item.IdMin;
dbShardingItem.ReadMode = item.ReadMode;
dbShardingItems.Add(dbShardingItem);
}
return(dbShardingItems);
}