private BindResult RebindOrderings(IList<OrderByDeclaration> orderings, TableAlias alias, HashSet<TableAlias> existingAliases, IList<ColumnDeclaration> existingColumns)
{
List<ColumnDeclaration> newColumns = null;
List<OrderByDeclaration> newOrderings = new List<OrderByDeclaration>();
foreach(OrderByDeclaration ordering in orderings)
{
SqlExpression expr = ordering.Expression;
ColumnExpression column = expr as ColumnExpression;
if(column == null || existingAliases != null && existingAliases.Contains(column.TableAlias))
{
int ordinal = 0;
foreach(ColumnDeclaration decl in existingColumns)
{
ColumnExpression declColumn = decl.Expression as ColumnExpression;
if(decl.Expression == ordering.Expression || column != null && declColumn != null && column.TableAlias == declColumn.TableAlias && column.ColumnName == declColumn.ColumnName)
{
expr = new ColumnExpression(alias, decl.DeclaredName);
break;
}
ordinal++;
}
if(expr == ordering.Expression)
{
if(newColumns == null)
{
newColumns = new List<ColumnDeclaration>(existingColumns);
existingColumns = newColumns;
}
string colName = column != null ? column.ColumnName : "c" + ordinal;
colName = GetAvailableColumnName(newColumns, colName);
newColumns.Add(new ColumnDeclaration(colName, ordering.Expression));
expr = new ColumnExpression(alias, colName);
}
newOrderings.Add(new OrderByDeclaration(ordering.OrderType, expr));
}
}
return new BindResult() { Columns = existingColumns, Orderings = newOrderings };
}
protected override Expression VisitInjected(InjectedExpression node)
{
SqlExpression sqlExpr = node.TranslateResult.SqlExpression;
if (sqlExpr.NodeType == SqlExpressionType.Column)
{
ColumnExpression column = (ColumnExpression)sqlExpr;
ColumnExpression mapped;
if (this.map.TryGetValue(column, out mapped))
{
return new InjectedExpression(new TranslateResult(mapped), node.Type);
}
foreach (ColumnDeclaration existingColumn in this.columns)
{
ColumnExpression c = existingColumn.Expression as ColumnExpression;
if (c != null && c.TableAlias == column.TableAlias && c.ColumnName == column.ColumnName)
{
return new InjectedExpression(new TranslateResult(new ColumnExpression(this.newAlias, existingColumn.DeclaredName)), node.Type);
}
}
if (this.existingAliases.Contains(column.TableAlias))
{
string declaredName = this.GetUniqueColumnName(column.ColumnName);
this.columns.Add(new ColumnDeclaration(declaredName, column));
mapped = new ColumnExpression(this.newAlias, declaredName);
this.map.Add(column, mapped);
return new InjectedExpression(new TranslateResult(mapped), node.Type);
}
return node;
}
else
{
string declaredName = this.GetNextColumnName();
this.columns.Add(new ColumnDeclaration(declaredName, sqlExpr));
return new InjectedExpression(new TranslateResult(new ColumnExpression(this.newAlias, declaredName)), node.Type);
}
}
protected override SqlExpression VisitColumn(ColumnExpression expr)
{
this.Write(GetAliasName(expr.TableAlias) + "." + expr.ColumnName + " ");
return expr;
}
public ColumnAssignment(ColumnExpression column, SqlExpression expression)
{
this.Column = column;
this.Expression = expression;
}