public void AddOrdering(SparqlOrdering ordering)
{
_ordering.Add(ordering);
}
private string GetSparqlQuery(bool withDatasetDescription, bool projectSortVariables = false)
{
var queryStringBuilder = new StringBuilder();
if (IsDistinct)
{
queryStringBuilder.Append("DISTINCT ");
}
foreach (var sv in _selectVars)
{
queryStringBuilder.AppendFormat("?{0} ", sv);
}
foreach (var ag in _aggregates)
{
queryStringBuilder.AppendFormat("({0} AS ?{1}) ", ag.Item2, ag.Item1);
}
if (projectSortVariables)
{
if (IsDistinct && _ordering.Count > 0)
{
// Eagerly loaded queries with DISTINCT and ordering need to be grouped by
// the select variable so that we can then use MIN and MAX aggregates to project the sort variables exactly once
_groupByExpressions.Add("?" + _selectVars[0]);
}
for (int i = 0; i < _ordering.Count; i++)
{
if (IsDistinct)
{
// Project MIN or MAX of the sort variable for consistency
queryStringBuilder.AppendFormat("({0}(?{1}_sort{2}) AS ?{1}_dsort{2}) ",
_ordering[i].OrderingDirection == OrderingDirection.Asc
? "MAX"
: "MIN",
_selectVars[0], i);
}
else
{
queryStringBuilder.AppendFormat("?{0}_sort{1} ", _selectVars[0], i);
}
}
}
if (withDatasetDescription)
{
AppendFromClause(queryStringBuilder);
}
queryStringBuilder
.Append("WHERE {")
.Append(_graphPatternBuilder.ToString());
if (projectSortVariables)
{
// Bind the expressions to variables
for (int i = 0; i < _ordering.Count; i++)
{
queryStringBuilder.AppendFormat(" BIND ({0} AS ?{1}_sort{2}) .",
_ordering[i].SelectorExpression, _selectVars[0], i);
}
}
queryStringBuilder.Append("}");
if (projectSortVariables && IsDistinct && IsOrdered)
{
// The ordering needs to be changed to use MIN and MAX expressions too
for (int i = 0; i < _ordering.Count; i++)
{
_ordering[i] = new SparqlOrdering(String.Format("{0}(?{1}_sort{2})",
_ordering[i].OrderingDirection ==
OrderingDirection.Asc
? "MAX"
: "MIN",
_selectVars[0], i),
_ordering[i].OrderingDirection);
}
}
AppendModifiers(queryStringBuilder);
var sparqlString = queryStringBuilder.ToString();
return(ReplaceFixedVariables(sparqlString));
}
public void AddOrdering(SparqlOrdering ordering)
{
_ordering.Add(ordering);
}
private string GetSparqlQuery(bool withDatasetDescription, bool projectSortVariables =false)
{
var queryStringBuilder = new StringBuilder();
if (IsDistinct) queryStringBuilder.Append("DISTINCT ");
foreach(var sv in _selectVars)
{
queryStringBuilder.AppendFormat("?{0} ", sv);
}
foreach(var ag in _aggregates)
{
queryStringBuilder.AppendFormat("({0} AS ?{1}) ", ag.Item2, ag.Item1);
}
if (projectSortVariables)
{
if (IsDistinct && _ordering.Count > 0)
{
// Eagerly loaded queries with DISTINCT and ordering need to be grouped by
// the select variable so that we can then use MIN and MAX aggregates to project the sort variables exactly once
_groupByExpressions.Add("?" + _selectVars[0]);
}
for (int i = 0; i < _ordering.Count; i++)
{
if (IsDistinct)
{
// Project MIN or MAX of the sort variable for consistency
queryStringBuilder.AppendFormat("({0}(?{1}_sort{2}) AS ?{1}_dsort{2}) ",
_ordering[i].OrderingDirection == OrderingDirection.Asc
? "MAX"
: "MIN",
_selectVars[0], i);
}
else
{
queryStringBuilder.AppendFormat("?{0}_sort{1} ", _selectVars[0], i);
}
}
}
if (withDatasetDescription) AppendFromClause(queryStringBuilder);
queryStringBuilder
.Append("WHERE {")
.Append(_graphPatternBuilder);
if (projectSortVariables)
{
// Bind the expressions to variables
for (int i = 0; i < _ordering.Count; i++)
{
queryStringBuilder.AppendFormat(" BIND ({0} AS ?{1}_sort{2}) .",
_ordering[i].SelectorExpression, _selectVars[0], i);
}
}
queryStringBuilder.Append("}");
if (projectSortVariables && IsDistinct && IsOrdered)
{
// The ordering needs to be changed to use MIN and MAX expressions too
for (int i = 0; i < _ordering.Count; i++)
{
_ordering[i] = new SparqlOrdering(String.Format("{0}(?{1}_sort{2})",
_ordering[i].OrderingDirection ==
OrderingDirection.Asc
? "MAX"
: "MIN",
_selectVars[0], i),
_ordering[i].OrderingDirection);
}
}
AppendModifiers(queryStringBuilder);
var sparqlString = queryStringBuilder.ToString();
return ReplaceFixedVariables(sparqlString);
}