public void CreateTableFromSchema()
{
EasyTable tables = FindTable(1);
EasyTable columnsTable = FindTable(2);
EasyBaseColumn column = tables.FindColumn("table_name");
int index = column.GetRowCount() - 1;
string tablename = (string)tables.FindColumn("table_name").GetValue(index);
EasyIntColumn inx = (EasyIntColumn)
columnsTable.FindColumn("table_name").Custom("=", tablename, EasyBaseColumn.IA);
List <CreateField> columns = new List <CreateField>();
for (int i = 0; i < inx.GetRowCount(); i++)
{
int j = (int)inx.GetValue(i);
CreateField field = new CreateField();
field.Name = (string)columnsTable.FindColumn("column_name").GetValue(j);
field.IsIdentity = (bool)columnsTable.FindColumn("is_identity").GetValue(j);
string data = (string)columnsTable.FindColumn("data_type").GetValue(j);
field.FieldType = Type.GetType("System." + data);
columns.Add(field);
}
CreateTableStructure(tablename, columns, 0, null);
}
private object ExecuteExpression(EasyTable table, List <string> list)
{
Stack <object> stack = new Stack <object>();
#region Postfix Notation
//TODO: apply paranthesis hack
for (int i = list.Count - 2; i > -1; i--)
{
if (list[i] == "|" || list[i] == "&" || list[i] == "=" ||
list[i] == "<" || list[i] == ">" ||
list[i] == "<=" || list[i] == ">=" ||
list[i] == "*" || list[i] == "/" ||
list[i] == "+" || list[i] == "-")
{
int k = 0;
for (int j = i + 1; j < list.Count; j++)
{
if (k == 0 && list[j] != "(")
{
string s = list[j];
list[j] = list[i];
list[i] = s;
break;
}
else //find matching parantheses
{
if (list[j] == "(")
{
k++;
}
else if (list[j] == ")")
{
k--;
}
if (k == 0)
{
string s = list[i];
for (int x = i; x < j; x++)
{
list[x] = list[x + 1];
}
list[j] = s;
break;
}
}
}
}
}
#endregion
foreach (var item in list)
{
if (item == "(" || item == ")")
{
continue;
}
if (item == "&" || item == "|" ||
item == ">" || item == ">=" || item == "<" || item == "<=" ||
item == "+" || item == "-" || item == "*" || item == "/" ||
item == "=" || item == "!=")
{
string msg = item;
object p2 = stack.Pop();
object p1 = stack.Pop();
//TODO: if p1 isConst swap p1,p2; msg = reverse(msg)
EasyBaseColumn column = null;
if (p1 is EasyBaseColumn)
{
column = (EasyBaseColumn)p1;
}
else
{
column = table.FindColumn((string)p1, true);
//TODO: if p1 and p2, are both id then use a special column to execute
//TODO: if(p2 is id) p2 = findCol(p2)
//object result = column.Message(msg, p2);
}
object result = null;
//if (msg != "=" || column.Index == null)
result = column.Custom(msg, p2, EasyBaseColumn.COLLECT);
//else
//{
// result = column.Index.Contains(new EasyConst() { Value = p2 });
// EasyBoolColumn b = new EasyBoolColumn();
// for (int i = 0; i < column.GetRowCount(); i++)
// {
// b.Insert(false);
// }
// //if (result != null) b.Values[1] = true;
// if (result != null) b.Values[((EasyValue)result).Index] = true;
// result = b;
//}
stack.Push(result);
continue;
}
stack.Push(item);
}
//TODO: stack can not contain more than one value
return(stack.Pop());
}
public DataTable Select(string tablename, List <string> fields, List <string> groupFields, WhereDelegate where)
{
if (groupFields != null && groupFields.Count == 0)
{
groupFields = null;
}
EasyTable table = FindTable(tablename);
EasyBoolColumn rows = null;
if (where != null)
{
rows = where ();
//rows = (EasyBoolColumn)rows.Custom("&", table.RowColumn, EasyBaseColumn.COLLECT);
}
DataTable dt = new DataTable();
//List<EasyBaseColumn> selectedFields = new List<EasyBaseColumn>();
Dictionary <string, EasyBaseColumn> selectedFields = new Dictionary <string, EasyBaseColumn>();
foreach (string field in fields)
{
if (field != "*")
{
EasyBaseColumn column = null;
if (SqlParser.IsId(field))
{
column = table.FindColumn(field);
//selectedFields.Add(column);
selectedFields[field] = column;
dt.Columns.Add(field, column.GetColumnType());
}
else
{
List <string> t = SqlParser.Tokenize(field);
column = (EasyBaseColumn)ExecuteExpression(table, t);
//selectedFields.Add(column);
selectedFields[field] = column;
dt.Columns.Add(field, column.GetColumnType());
}
}
else
{
foreach (var column in table.Columns)
{
//selectedFields.Add(column);
selectedFields[column.Name] = column;
dt.Columns.Add(column.Name, column.GetColumnType());
}
}
}
//if (rows != null)
// {
int k = 0;
int rowCount = 0;
foreach (EasyBaseColumn column in selectedFields.Values)
{
rowCount = column.GetRowCount();
break;
}
Hashtable previousValues = new Hashtable();
for (int i = 0; i < rowCount; i++)
{
if (rows != null && !rows.Values[i])
{
continue;
}
if (table.RowColumn.Values[i] == 0)
{
continue;
}
int j = 0;
bool group = false;
if (groupFields != null)
{
group = true;
foreach (string groupField in groupFields)
{
if (k > 0)
{
object val = selectedFields[groupField].GetValue(i);
if (!selectedFields[groupField].EQ(val, previousValues[groupField]))
{
group = false;
previousValues[groupField] = val;
}
}
else
{
group = false;
previousValues[groupField] = selectedFields[groupField].GetValue(i);
}
}
}
if (group)
{
continue;
}
dt.Rows.Add();
foreach (EasyBaseColumn column in selectedFields.Values)
{
dt.Rows[k][j] = column.GetValue(i);
j++;
}
k++;
}
//}
//else
//{
// int k = 0;
// int rowCount = 0;
// foreach (EasyBaseColumn column in selectedFields.Values)
// {
// rowCount = column.GetRowCount();
// break;
// }
// for (int i = 0; i < rowCount; i++)
// {
// if (table.RowColumn.Values[i] == 0) continue;
// dt.Rows.Add();
// int j = 0;
// foreach (EasyBaseColumn column in selectedFields.Values)
// {
// dt.Rows[k][j] = column.GetValue(i);
// j++;
// }
// k++;
// }
//}
return(dt);
}