internal bool ExecuteQuery()
{
try
{
if (!QueryAnalyze())
{
return(false);
}
//got
if (this.selectedRelations.Count == 2) // có 2 rel
{
if (flagNaturalJoin != true) //xe truong hop
{
this.selectedRelations[0] = Descartes();
}
else
{
this.selectedRelations[0] = NaturalJoin();
}
}
else
{
foreach (ProbAttribute attr in this.selectedRelations[0].Scheme.Attributes)
{
if (!attr.AttributeName.Contains("."))
{
attr.AttributeName = String.Format("{0}.{1}", this.selectedRelations[0].RelationName, attr.AttributeName);
}
}
}
if (!this.queryString.Contains("where")) //query ko co where
{
this.relationResult = getRelationBySelectAttribute(this.selectedRelations[0], this.selectedAttributes); // lay danh sach att
return(true);
}
else
{
SelectCondition Condition = new SelectCondition(this.selectedRelations[0], this.conditionString);
if (!Condition.CheckConditionString())
{
this.MessageError = Condition.MessageError;
return(false);
}
foreach (ProbTuple tuple in this.selectedRelations[0].tuples)
{
if (Condition.Satisfied(tuple))
{
this.relationResult.tuples.Add(tuple);
}
}
if (Condition.MessageError != string.Empty)
{
this.MessageError = Condition.MessageError;
return(false);
}
if (Condition.conditionString == string.Empty)
{
this.MessageError = Condition.MessageError;
return(false);
}
this.relationResult.Scheme = this.selectedRelations[0].Scheme;
this.relationResult = getRelationBySelectAttribute(this.relationResult, this.selectedAttributes);
}
}
catch
{
return(false);
}
return(true);
}
internal bool ExcuteQuery()
{
try
{
if (!QueryAnalyze())
{
return(false);
}
if (this.selectedRelations.Count == 1)
{
foreach (ProbAttribute attr in this.selectedRelations[0].Scheme.Attributes)
{
if (!attr.AttributeName.Contains("."))
{
attr.AttributeName = String.Format("{0}.{1}", this.selectedRelations[0].RelationName, attr.AttributeName);
}
}
}
else
{
if (flagNaturalJoin != true)
{
var relationRes = this.selectedRelations[0];
for (int i = 1; i < this.selectedRelations.Count(); i++)
{
relationRes = Descartes(relationRes, this.selectedRelations[i]);
}
this.selectedRelations[0] = relationRes;
}
else
{
var relationRes = this.selectedRelations[0];
for (int i = 1; i < this.selectedRelations.Count(); i++)
{
relationRes = NaturalJoin(relationRes, this.selectedRelations[i], this.OperationNaturalJoin[i - 1]);
}
this.selectedRelations[0] = relationRes;
}
}
if (!this.queryString.Contains(Common.Where))
{
this.relationResult = getRelationBySelectAttributeV2(this.selectedRelations[0], this.selectedAttributes);
return(true);
}
else
{
SelectCondition Condition = new SelectCondition(this.selectedRelations[0], this.conditionString);
Condition.ProcessConditionString();
if (!string.IsNullOrEmpty(Condition.MessageError))
{
MessageError = Condition.MessageError;
return(false);
}
foreach (ProbTuple tuple in this.selectedRelations[0].tuples)
{
if (Condition.Satisfied(tuple))
{
this.relationResult.tuples.Add(tuple);
}
else
{
if (!string.IsNullOrEmpty(Condition.MessageError))
{
MessageError = Condition.MessageError;
return(false);
}
}
}
if (Condition.MessageError != string.Empty)
{
this.MessageError = Condition.MessageError;
return(false);
}
if (Condition.conditionString == string.Empty)
{
this.MessageError = Condition.MessageError;
return(false);
}
this.relationResult.Scheme = this.selectedRelations[0].Scheme;
this.relationResult = getRelationBySelectAttribute(this.relationResult, this.selectedAttributes);
}
}
catch
{
return(false);
}
return(true);
}