/// <summary>
/// Visits the relation in a where clause.
/// </summary>
/// <param name="node"> The node. </param>
/// <returns> </returns>
public virtual Expression VisitRelation(RelationExpression node)
{
return base.VisitExtension(node);
}
public override Expression VisitRelation(RelationExpression relation)
{
base.VisitRelation(relation);
var builder = new StringBuilder();
builder.Append(_translations[relation.Selector]);
switch ((CqlExpressionType)relation.NodeType)
{
case CqlExpressionType.Equal:
builder.Append("=");
builder.Append(_translations[relation.Term]);
break;
case CqlExpressionType.LargerEqualThan:
builder.Append(">=");
builder.Append(_translations[relation.Term]);
break;
case CqlExpressionType.LargerThan:
builder.Append(">");
builder.Append(_translations[relation.Term]);
break;
case CqlExpressionType.SmallerEqualThan:
builder.Append("<=");
builder.Append(_translations[relation.Term]);
break;
case CqlExpressionType.SmallerThan:
builder.Append("<");
builder.Append(_translations[relation.Term]);
break;
case CqlExpressionType.In:
builder.Append(" IN ");
if(((CqlExpressionType)relation.Term.NodeType == CqlExpressionType.Variable))
{
builder.Append(_translations[relation.Term]);
}
else
{
builder.Append("(");
var elements = relation.Term.Terms.Select(term => _translations[term]);
builder.Append(string.Join(",", elements));
builder.Append(")");
}
break;
default:
throw new CqlLinqException("Unexpected relation encountered in where: " +
relation.NodeType.ToString());
}
_translations[relation] = builder.ToString();
return relation;
}
protected override Expression VisitChildren(ExpressionVisitor visitor)
{
bool changed = false;
var selectClause = (SelectClauseExpression) visitor.Visit(_selectClause);
changed |= selectClause != _selectClause;
int count = _whereClause.Count;
var wheres = new RelationExpression[count];
for (int i = 0; i < count; i++)
{
wheres[i] = (RelationExpression) visitor.Visit(_whereClause[i]);
changed |= wheres[i] != _whereClause[i];
}
count = _orderBy.Count;
var order = new OrderingExpression[count];
for (int i = 0; i < count; i++)
{
order[i] = (OrderingExpression) visitor.Visit(_orderBy[i]);
changed |= order[i] != _orderBy[i];
}
return changed
? new SelectStatementExpression(_type, selectClause, _tableName, wheres, order, _limit,
_allowFiltering)
: this;
}
