public override object LoadScalar(OPath.OPathQuery query)
{
if (query.QueryType == OPathQueryTypeEnum.Path)
{
query.QueryType = OPathQueryTypeEnum.Expression;
query.Expression = new OPath.Expressions.Call("eval", new Evaluant.OPath.Expressions.Collections.ConstraintCollection(new OPath.Expressions.Constraint[] { query.Path }));
}
SqlMapperTransformer transformer = new SqlMapperTransformer(_Mapping, _Model);
transformer.Dialect = Dialect;
ISQLExpression exp = transformer.TransformScalar(query);
_Connection.Open();
_Transaction = _Connection.BeginTransaction();
object result = null;
try
{
string[] queries = Dialect.RenderQueries(exp);
IDbCommand command = Driver.CreateCommand(queries[queries.Length - 1], _Connection, _Transaction);
if (TraceSqlSwitch.Enabled)
{
TraceHelpler.Trace(command, _Dialect);
}
object res = command.ExecuteScalar();
if (res != DBNull.Value)
result = res;
_Transaction.Commit();
}
catch
{
_Transaction.Rollback();
throw;
}
finally
{
_Connection.Close();
}
// Ensure the result in an Int32 in case of a count()
if (query.Expression.Operands[0] is OPath.Expressions.Function
&& ((OPath.Expressions.Function)query.Expression.Operands[0]).Type == Evaluant.OPath.Expressions.FunctionEnum.Count)
result = Convert.ToInt32(result);
return result;
}
