public SqlSelectStatement()
{
IsDistinct = false;
OutputColumnsRenamed = false;
OutputColumns = null;
AllJoinExtents = null;
FromExtents = new List <Symbol>();
OuterExtents = new Dictionary <Symbol, bool>();
Top = new TopClause();
Select = new SelectColumnList();
From = new SqlBuilder();
Where = new SqlBuilder();
GroupBy = new SqlBuilder();
OrderBy = new SqlBuilder();
IsTopMost = false;
}
/// <summary>
/// We assume that this is only called as a child of a Project.
///
/// This replaces <see cref="Visit(DbNewInstanceExpression)"/>, since
/// we do not allow DbNewInstanceExpression as a child of any node other than
/// DbProjectExpression.
///
/// We write out the translation of each of the columns in the record.
/// </summary>
/// <param name="e"></param>
/// <returns>A <see cref="SqlBuilder"/></returns>
ISqlFragment VisitNewInstanceExpression(DbNewInstanceExpression e)
{
var result = new SelectColumnList();
var rowType = e.ResultType.EdmType as RowType;
if (rowType != null)
{
var members = rowType.Properties;
for (int i = 0; i < e.Arguments.Count; ++i)
{
var argument = e.Arguments[i];
if (MetadataHelpers.IsRowType(argument.ResultType))
{
// We do not support nested records or other complex objects.
throw new NotSupportedException();
}
EdmProperty member = members[i];
var expression = argument.Accept(this);
var columnSymbol = expression as ColumnSymbol;
if (columnSymbol != null)
{
result.Append(new SelectColumn(new Symbol(member.Name, member.TypeUsage), columnSymbol.Source, columnSymbol.Column));
}
else
{
result.Append(new SelectColumn(new Symbol(member.Name, member.TypeUsage), expression));
}
}
}
else
{
//
// Types other then RowType (such as UDTs for instance) are not supported.
//
throw new NotSupportedException();
}
return(result);
}
/// <summary>
/// <see cref="Visit(DbFilterExpression)"/> for the general ideas.
/// </summary>
/// <param name="e"></param>
/// <returns>A <see cref="SqlSelectStatement"/></returns>
/// <seealso cref="Visit(DbFilterExpression)"/>
public override ISqlFragment Visit(DbProjectExpression e)
{
Symbol fromSymbol;
var inputSelect = VisitInputExpression(e.Input.Expression, e.Input.VariableName, e.Input.VariableType, out fromSymbol);
var select = inputSelect;
// Project is compatible with Filter
// but not with Project, GroupBy
if (!IsCompatible(inputSelect, e.ExpressionKind))
{
select = CreateNewSelectStatement(inputSelect, e.Input.VariableName, e.Input.VariableType, out fromSymbol);
select.Top.SetTopClause(inputSelect.Top);
//select.OrderBy.Set(inputSelect.OrderBy);
inputSelect.Top.Clear();
//inputSelect.OrderBy.Clear();
}
selectStatementStack.Push(select);
symbolTable.EnterScope();
AddFromSymbol(select, e.Input.VariableName, fromSymbol);
// Project is the only node that can have DbNewInstanceExpression as a child
// so we have to check it here.
// We call VisitNewInstanceExpression instead of Visit(DbNewInstanceExpression), since
// the latter throws.
if (e.Projection is DbNewInstanceExpression)
{
select.Select.Append(VisitNewInstanceExpression((DbNewInstanceExpression)e.Projection) as IEnumerable <SelectColumn>);
if ((select != inputSelect) && (select.Select.Count == inputSelect.Select.Count))
{
var newSelect = new SelectColumnList();
var inputColumns = inputSelect.Select.ToDictionary(x => x.Column.Name, x => x);
foreach (var column in select.Select)
{
if (!column.IsSimple)
{
break;
}
SelectColumn inputColumn;
if (inputColumns.TryGetValue(column.InnerName.Name, out inputColumn))
{
newSelect.Append(new SelectColumn(new Symbol(column.InnerName.Name), inputColumn.Expression));
}
else
{
break;
}
}
if (inputColumns.Count == select.Select.Count)
{
inputSelect.Select = newSelect;
inputSelect.Top.SetTopClause(select.Top);
//inputSelect.OrderBy.Set(select.OrderBy);
select = inputSelect;
}
}
}
else
{
select.Select.Append(e.Projection.Accept(this) as IEnumerable <SelectColumn>);
}
symbolTable.ExitScope();
selectStatementStack.Pop();
return(select);
}
