protected static Column createColumn(string name, View view, Column.DataType type = Column.DataType.Text)
{
Column column = new Column();
column.name = name;
column.Type = type;
return(view.AddColumn(column));
}
public RecordComparer(int index, Column.DataType type)
{
this.type = type;
this.index = index;
}
/**
* Query:
* SELECT [*] [col_1, col_2]
* FROM table_1
* [WHERE] ((col_3 = val_3) AND (col_4 = col_5))
* [ORDER BY] col_name [ASC|DESC]
*/
private void SelectRecordsFromTable()
{
ParseTreeNode topNode = root.ChildNodes[0];
//Selecting the table
ParseTreeNode tableListNode = topNode
.ChildNodes[4].ChildNodes[1];
String tableName = tableListNode.ChildNodes[0].ChildNodes[0].Token.ValueString;
//Selecting the columns
ParseTreeNode colList = topNode.ChildNodes[2].ChildNodes[0];
List <int> selectedColumns;
if (colList.ChildNodes.Count == 0) //'*' clause
{
selectedColumns = subQueryHandler.GetColumnIndicesFromName(tableName, new List <string>());
}
else
{
List <String> colNames = new List <string>();
foreach (var colNameNode in colList.ChildNodes)
{
String colName = colNameNode.ChildNodes[0].ChildNodes[0].ChildNodes[0].Token.ValueString;
colNames.Add(colName);
}
selectedColumns = subQueryHandler.GetColumnIndicesFromName(tableName, colNames);
}
//Selecting the records
Dictionary <int, Record> possibleRecords;
if (topNode.ChildNodes[5].ChildNodes.Count > 1)
{
ParseTreeNode binExpr = topNode.ChildNodes[5].ChildNodes[1];
possibleRecords = SolveWhereClause(tableName, binExpr);
}
else
{
possibleRecords = subQueryHandler.SelectRecordsFromTable(tableName, null);
}
//Getting the order by clause
List <Record> orderedList = new List <Record>(possibleRecords.Values);
if (topNode.ChildNodes[8].ChildNodes.Count > 1)
{
ParseTreeNode orderByNode = topNode.ChildNodes[8].ChildNodes[2];
String orderByColName = orderByNode.ChildNodes[0]
.ChildNodes[0].ChildNodes[0].Token.ValueString;
List <String> orderByList = new List <string>(1);
orderByList.Add(orderByColName);
int toSortIndex = subQueryHandler.GetColumnIndicesFromName(tableName, orderByList)[0];
Column.DataType toSortType = subQueryHandler.DescribeTable(tableName).Columns[toSortIndex].Type;
String orderByType = "asc";
if (orderByNode.ChildNodes[0].ChildNodes[1].ChildNodes.Count > 0)
{
orderByType = orderByNode.ChildNodes[0].ChildNodes[1]
.ChildNodes[0].Token.ValueString;
}
orderedList.Sort(new RecordComparer(toSortIndex, toSortType));
if (orderByType == "desc")
{
orderedList.Reverse();
}
}
//Displaying the heading of selected records
List <String> sortedSelectedCols = subQueryHandler.SortColumnsInOrder(tableName, selectedColumns);
foreach (String colName in sortedSelectedCols)
{
_messenger.Message(colName + "|");
}
//Dispaly the records in proper format
foreach (Record record in orderedList)
{
List <String> fields = record.Fields;
String recAsString = "";
foreach (int index in selectedColumns)
{
recAsString += (fields[index] + " | ");
}
_messenger.Message(recAsString);
}
}
