/// <summary>
/// execute query
/// </summary>
/// <typeparam name="T">data type</typeparam>
/// <param name="cmd">command</param>
/// <returns>datas</returns>
public async Task <IEnumerable <T> > QueryAsync <T>(ICommand cmd)
{
var servers = await GetServerAsync(cmd).ConfigureAwait(false);
VerifyServerEngine(servers.Select(c => c.ServerType).ToArray());
IEnumerable <T> dataList = null;
if (servers.Count == 1)
{
var nowServer = servers[0];
var engine = DataManager.DbEngines[nowServer.ServerType];
dataList = engine.Query <T>(nowServer, cmd);
}
else
{
bool notOrder = cmd.Query == null || cmd.Query.Orders.IsNullOrEmpty();
int dataSize = cmd.Query?.QuerySize ?? 0;
var entityCompare = new EntityCompare <T>();
foreach (var server in servers)
{
var engine = DataManager.DbEngines[server.ServerType];
var newDataList = await engine.QueryAsync <T>(server, cmd).ConfigureAwait(false);
dataList = dataList == null ? newDataList : dataList.Union(newDataList, entityCompare);//merge data
if (dataSize > 0 && dataList.Count() >= dataSize && notOrder)
{
return(dataList.Take(dataSize));
}
}
if (!notOrder)
{
dataList = cmd.Query.Order(dataList);
}
if (dataSize > 0 && dataList.Count() > dataSize)
{
dataList = dataList.Take(dataSize);
}
}
return(dataList);
}
/// <summary>
/// Query datas
/// </summary>
/// <typeparam name="T">Data type</typeparam>
/// <param name="command">Command</param>
/// <returns>Return datas</returns>
public async Task <IEnumerable <T> > QueryAsync <T>(ICommand command)
{
var servers = GetServers(command);
VerifyServerProvider(servers.Select(c => c.ServerType));
IEnumerable <T> datas = null;
if (servers.Count == 1)
{
var nowServer = servers[0];
var provider = DataManager.GetDatabaseProvider(nowServer.ServerType);
datas = provider.Query <T>(nowServer, command);
}
else
{
bool notOrder = command.Query == null || command.Query.Orders.IsNullOrEmpty();
int dataSize = command.Query?.QuerySize ?? 0;
var entityCompare = new EntityCompare <T>();
Task <IEnumerable <T> >[] queryTasks = new Task <IEnumerable <T> > [servers.Count];
int serverIndex = 0;
foreach (var server in servers)
{
var provider = DataManager.GetDatabaseProvider(server.ServerType);
queryTasks[serverIndex] = provider.QueryAsync <T>(server, command);
serverIndex++;
}
datas = (await Task.WhenAll(queryTasks).ConfigureAwait(false)).SelectMany(c => c).Distinct(entityCompare);
if (!notOrder)
{
datas = command.Query.Sort(datas);
}
if (dataSize > 0 && datas.Count() > dataSize)
{
datas = datas.Take(dataSize);
}
}
return(datas);
}
