Expression ParseAndExpression()
{
Expression lNode = ParseOrExpression();
while (!AtEndOfSource && (fCurrentToken.Equals("AND") || fCurrentToken.Equals("&&")))
{
ReadNextToken(); // skip '&&'
lNode = new AndExpression(lNode, ParseOrExpression());
}
return lNode;
}
private void execute(Statement statement, Context context)
{
if (statement is SelectStatement)
{
// Join'den tabloları al
// her bir kayıt için hashtable oluştur, context'e ekle, where expressionı üzerinde excute ettir. true ise listeye ekle.
// falan filan uzun iş bu. niye yapıyorum ki ben bunu?
SelectStatement ss = statement as SelectStatement;
Expression filter = null;
if (ss.From[0].On == null && ss.Where == null) filter = null;
else if (ss.From[0].On != null && ss.Where != null) filter = new AndExpression(ss.From[0].On, ss.Where);
else if (ss.From[0].On != null) filter = ss.From[0].On;
else filter = ss.Where;
this.FieldNames = ss.Select;
this.ResultSet = context.GetData(ss.From[0], filter, ss.Select);
this.FieldTypes = new List<Type>();
if (this.ResultSet.Count > 0)
{
foreach (Select key in ss.Select)
if (this.ResultSet[0][key.Alias] != null)
this.FieldTypes.Add(this.ResultSet[0][key.Alias].GetType());
else
this.FieldTypes.Add(typeof(string));
}
if (ss.OrderBy.Count > 0)
{
IOrderedEnumerable<Hashtable> orderedList = this.ResultSet.OrderBy(ht=>1);
for (int i = 0; i < ss.OrderBy.Count; i++)
{
object orderBy = null;
if (ss.OrderBy[i].By is IntegerConstant)
orderBy = ((IntegerConstant)ss.OrderBy[i].By).Value;
else
orderBy = ((DbObjectName)ss.OrderBy[i].By).Name;
if (orderBy.GetType() == typeof(int))
{
int fieldNo = (int)orderBy - 1;
if (!(fieldNo < 0 || fieldNo >= FieldNames.Count))
{
if (ss.OrderBy[i].Desc)
orderedList = orderedList.ThenByDescending(ht => ht[FieldNames[(int)fieldNo].Alias]);
else
orderedList = orderedList.ThenBy(ht => ht[FieldNames[(int)fieldNo].Alias]);
}
}
else
{
string alias = orderBy.ToString();
if (FieldNames.IndexOf(alias) > -1)
{
if (ss.OrderBy[i].Desc)
orderedList = orderedList.ThenByDescending(ht => ht[alias]);
else
orderedList = orderedList.ThenBy(ht => ht[alias]);
}
}
}
this.ResultSet = orderedList.ToList();
}
if (ss.Limit != null)
{
int offset = ss.Offset == null ? 0 : Convert.ToInt32(ss.Offset.Calculate(context));
int limit = Convert.ToInt32(ss.Limit.Calculate(context));
this.ResultSet = this.ResultSet.Skip(offset).Take(limit).ToList();
}
}
}