public SelectStatement(ITagMapping tag): base(tag)
{
SelectList = new ExpressionCollection();
_IsDistinct = false;
_SelectedAllColumns = false;
_Limit = 0;
_Offset = 0;
_FromClause = new FromClause();
_WhereClause = new WhereClause(BinaryLogicOperator.And);
_OrderByClause = new OrderByClause(this);
}
public override void Visit(FromClause from_clause)
{
if (from_clause.Count > 0)
base.Visit(from_clause);
else
_Query.Append(FROM).Append(DUAL); // DUAL is a dummy table ever existing
}
private string GetParentTableName(FromClause from)
{
string parentTableName = string.Empty;
Table t = from[from.Count - 1];
if (t.GetType() == typeof(TableSource))
parentTableName = t.TableAlias;
else
{
if (t.GetType() == typeof(JoinedTable))
{
while (t.GetType() == typeof(JoinedTable))
{
t = ((JoinedTable)t).RigthTable;
if (t.GetType() == typeof(TableSource))
break;
}
parentTableName = t.TableAlias;
}
}
return parentTableName;
}
public virtual void Visit(FromClause from_clause)
{
if(from_clause.Count > 0)
_Query.Append(FROM);
foreach(Table table in from_clause)
{
if (IsSelectStatement(table))
_Query.Append(OPENBRACE);
table.Accept(this);
if (IsSelectStatement(table))
{
_Query.Append(CLOSEBRACE).Append(FormatTableAlias(table.TableAlias)).Append(SPACE);
}
if ( from_clause.IndexOf(table) != from_clause.Count - 1 )
_Query.Append(COMMA);
}
}