/// <summary>
/// Executes the query and returns the first column of the first row in the result set returned by the query. All other columns and rows are ignored.
/// </summary>
/// <returns> The first column of the first row in the result set. </returns>
public override object ExecuteScalar()
{
object ret = null;
BindParameters();
using (CUBRIDDataReader dr = ExecuteInternal())
{
if (dr.Read())
{
ret = dr.GetValue(0);
}
if (ret == null)
{
if (dr.GetColumnCount() != 0)
{
ret = DBNull.Value;
}
}
dr.Close();
}
return(ret);
}
private void LoadTableColumns(DataTable dt, string tableName, string columnRestriction)
{
string sql =
String.Format(
"select * from db_attribute where class_name like '{0}' and attr_name like '{1}' order by def_order asc",
tableName, columnRestriction);
using (CUBRIDCommand cmd = new CUBRIDCommand(sql, conn))
{
int pos = 1;
using (CUBRIDDataReader reader = (CUBRIDDataReader)cmd.ExecuteReader())
{
while (reader.Read())
{
string colName = reader.GetString(0);
DataRow row = dt.NewRow();
row["TABLE_CATALOG"] = conn.Database;
row["TABLE_SCHEMA"] = conn.Database;
row["TABLE_NAME"] = tableName;
row["COLUMN_NAME"] = colName;
row["ORDINAL_POSITION"] = pos++;
for (int i = 0; i < reader.GetColumnCount(); i++)
{
switch (reader.GetColumnName(i))
{
case "defalut_value":
row["COLUMN_DEFAULT"] = reader.GetString(i);
break;
case "is_nullable":
row["IS_NULLABLE"] = reader.GetString(i).Equals("YES");
break;
case "data_type":
row["DATA_TYPE"] = reader.GetString(i);
break;
case "prec":
row["NUMERIC_PRECISION"] = reader.GetInt(i);
break;
case "scale":
row["NUMERIC_SCALE"] = reader.GetInt(i);
break;
case "code_set":
case "charset":
row["CHARACTER_SET"] = reader.GetString(i);
break;
default:
break;
}
}
dt.Rows.Add(row);
}
}
}
}