/// <summary>
/// 构造函数
/// </summary>
/// <param name="baseDbContext">BaseDbContext</param>
public GenericDbAccessor(GenericDbContext baseDbContext)
{
_db = baseDbContext;
_provider = DbFactory.GetProvider(DbType);
}
public async Task <List <T> > ToListAsync()
{
//去除分页,获取前Take+Skip数量
int?take = _source.GetTakeCount();
int?skip = _source.GetSkipCount();
skip = skip == null ? 0 : skip;
var(sortColumn, sortType) = _source.GetOrderBy();
var noPaginSource = _source.RemoveTake().RemoveSkip();
if (!take.IsNullOrEmpty())
{
noPaginSource = noPaginSource.Take(take.Value + skip.Value);
}
//从各个分表获取数据
var tables = ShardingConfig.ConfigProvider.GetReadTables(_absTableName, _absDbName, _source);
SynchronizedCollection <IDbAccessor> dbs = new SynchronizedCollection <IDbAccessor>();
List <Task <List <T> > > tasks = tables.Select(aTable =>
{
var targetTable = MapTable(aTable.tableName);
IDbAccessor db;
if (_repository.OpenedTransaction)
{
db = _repository.GetMapDbAccessor(aTable.conString, aTable.dbType);
}
else
{
db = DbFactory.GetDbAccessor(aTable.conString, aTable.dbType);
}
dbs.Add(db);
var targetIQ = db.GetIQueryable(targetTable);
var newQ = noPaginSource.ChangeSource(targetIQ);
return(newQ
.Cast <object>()
.Select(x => x.ChangeType <T>())
.ToListAsync());
}).ToList();
List <T> all = new List <T>();
(await Task.WhenAll(tasks.ToArray())).ToList().ForEach(x => all.AddRange(x));
if (!_repository.OpenedTransaction)
{
dbs.ForEach(x => x.Dispose());
}
//合并数据
var resList = all;
if (!sortColumn.IsNullOrEmpty() && !sortType.IsNullOrEmpty())
{
resList = resList.AsQueryable().OrderBy($"{sortColumn} {sortType}").ToList();
}
if (!skip.IsNullOrEmpty())
{
resList = resList.Skip(skip.Value).ToList();
}
if (!take.IsNullOrEmpty())
{
resList = resList.Take(take.Value).ToList();
}
return(resList);
}
/// <summary>
/// 构造函数
/// </summary>
/// <param name="baseDbContext">BaseDbContext</param>
public AbstractDbAccessor(BaseDbContext baseDbContext)
{
_db = baseDbContext;
_provider = DbFactory.GetProvider(DbType);
}
/// <summary>
/// 转为Sharding
/// </summary>
/// <typeparam name="T">实体泛型</typeparam>
/// <param name="source">数据源</param>
/// <param name="absDbName">抽象数据库</param>
/// <returns>IShardingQueryable</returns>
public static IShardingQueryable <T> ToSharding <T>(this IQueryable <T> source, string absDbName = ShardingConfig.DefaultAbsDbName) where T : class, new()
{
ShardingConfig.CheckInit();
return(new ShardingQueryable <T>(source, DbFactory.GetShardingDbAccessor(absDbName) as ShardingDbAccessor, absDbName));
}