public List <IDictionary <string, object> > Take(int count)
{
ExecutionPlan executionplan = QueryPraser.GetExecutionPlan(this);
List <long> list = GetList(executionplan, count);
List <IDictionary <string, object> > listvalue = new List <IDictionary <string, object> >();
foreach (var item in list)
{
var record = this.table._getvalue(item);
listvalue.Add(record);
}
if (!executionplan.RequireOrderBy)
{
return(listvalue);
}
else
{
if (!string.IsNullOrEmpty(this.OrderByFieldName) && this.table.Setting.Columns.Any(o => o.Name == this.OrderByFieldName))
{
var col = this.table.Setting.Columns.First(o => o.Name == this.OrderByFieldName);
if (col != null)
{
if (this.Ascending)
{
return(listvalue.OrderBy(o => GetValue(o, this.OrderByFieldName, col.ClrType)).Skip(this.SkipCount).Take(count).ToList());
}
else
{
return(listvalue.OrderByDescending(o => GetValue(o, this.OrderByFieldName, col.ClrType)).Skip(this.SkipCount).Take(count).ToList());
}
}
}
return(listvalue.Skip(this.SkipCount).Take(count).ToList());
}
}
public List <FilterItem> ParserFilter(string conditiontext)
{
var conditions = QueryPraser.ParseConditoin(conditiontext);
if (conditions == null || conditions.Count() == 0)
{
return(null);
}
;
List <FilterItem> result = new List <FilterItem>();
foreach (var item in conditions)
{
var col = this.table.ObjectConverter.Fields.Find(o => o.FieldName == item.Field);
if (col != null)
{
FilterItem filter = new FilterItem()
{
FieldOrProperty = col.FieldName
};
filter.Compare = item.Comparer;
if (!col.ClrType.IsValueType && col.ClrType != typeof(string))
{
throw new Exception("only value type column are allowed to use on search condition");
}
var rightvalue = Convert.ChangeType(item.Value, col.ClrType);
// For datetime col, need to have something different.
if (rightvalue != null)
{
filter.Value = col.ToBytes(rightvalue);
result.Add(filter);
}
}
}
return(result);
}
public int Count()
{
lock (this.table._Locker)
{
int skipped = 0;
int taken = 0;
ExecutionPlan executionplan = QueryPraser.GetExecutionPlan(this);
List <List <long> > rangelist = new List <List <long> >();
foreach (var item in executionplan.indexRanges)
{
List <long> blockpositionList = new List <long>();
var index = this.table.Indexs.Find(o => o.FieldName == item.Key);
ItemCollection collection = index.GetCollection(item.Value.lower, item.Value.upper, item.Value.lowerOpen, item.Value.upperOpen, this.Ascending);
foreach (Int64 position in collection)
{
blockpositionList.Add(position);
}
rangelist.Add(blockpositionList);
}
bool itemMatch = true;
foreach (Int64 item in executionplan.startCollection)
{
/// check matches.
itemMatch = true;
foreach (List <long> rangeitem in rangelist)
{
if (!rangeitem.Contains(item))
{
itemMatch = false;
break;
}
}
if (!itemMatch)
{
continue;
}
/// check column matchs.
foreach (ColumnScan plan in executionplan.scanColumns)
{
byte[] columnbytes = this.table.BlockFile.GetCol(item, plan.relativeStartPosition, plan.length);
if (!plan.Evaluator.isMatch(columnbytes))
{
itemMatch = false;
break;
}
}
if (!itemMatch)
{
continue;
}
/// pass all tests.
if (skipped < this.SkipCount)
{
skipped += 1;
continue;
}
taken += 1;
}
executionplan = null;
return(taken);
}
}
