Output parameters not populating MSSQL ODBC - c++

Question

I'm having problems getting this code to populate output parameters with MSSQL ODBC 10.0 client driver and 9.0 as well. I can confirm my binding direction is being set properly.
I am also calling SQLMoreResults, my stored procedure has NOCOUNT set and works fine under another ODBC-based library.
Unfortunately once I get to my execute statement, it succeeds but SQLMoreResults always says there are no more results, and I realize that those parameters aren't populated until it has gone through all of the result sets. The one output parameter I use is a bigint.
Unfortunately I don't know all of the intricacies of ODBC development and there must be something important I'm missing. I do try to reuse my statement handle but I reset it after my first call to SQLProcedureColumns and remove bound variables. Then I rebind.
Any ideas as to where I'm going astray?
bool ODBCConnection::Execute()
{
LLOG("Execute " << (void *)this << " " << (void *)session);
if(session->hstmt == SQL_NULL_HANDLE)
return false;
if(IsCurrent())
session->current = NULL;
session->FlushConnections();
last_insert_table.Clear();
number.Clear();
text.Clear();
time.Clear();
CParser p(statement);
/* parse for stored procedure */
bool isStoredProcedure = false;
if (p.Char('{'))
{
p.Spaces();
String procedure_name;
p.Id("?");
p.Id("=");
if (p.Id("call") || p.Id("CALL")) {
procedure_name = p.ReadId();
isStoredProcedure = true;
//Cout() << "Proc name: " << procedure_name << "\n";
}
SQLSetEnvAttr(session->henv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER) SQL_OV_ODBC3, SQL_IS_INTEGER);
SDWORD cbValue5;
SDWORD cbValue4;
SQLSMALLINT ParameterType = SQL_PARAM_INPUT;
if (!IsOk(SQLProcedureColumns (
session->hstmt,
NULL,
0,
NULL,
0,
(SQLCHAR *)~procedure_name,
procedure_name.GetLength(),
NULL,
0
))) {
SQLFreeStmt(session->hstmt, SQL_CLOSE);
return false;
}
char parameter_name [20];
if (!IsOk(SQLBindCol(
session->hstmt,
4, // Column 4 returns column name
SQL_C_CHAR,
parameter_name,
sizeof(parameter_name),
&cbValue4
))) {
}
if (!IsOk(SQLBindCol(
session->hstmt,
5, // Column 5 returns whether parameter is input or output
SQL_C_SHORT,
&ParameterType,
0,
&cbValue5
))) {
}
int i = 0;
while (SQLFetch(session->hstmt) == SQL_SUCCESS) {
Param& p = param[i];
Cout() << ParameterType << "\n";
/*switch (ParameterType) {
case SQL_PARAM_INPUT:
case SQL_PARAM_OUTPUT:
case SQL_PARAM_INPUT_OUTPUT:
p.direction = ParameterType;
break;
case 5:
p.direction = SQL_PARAM_OUTPUT;
break;
default:
break;
}*/
if(ParameterType == 5)
p.direction = SQL_PARAM_OUTPUT;
else
p.direction = ParameterType;
i++;
}
SQLFreeStmt(session->hstmt, SQL_CLOSE);
SQLFreeStmt(session->hstmt, SQL_RESET_PARAMS);
SQLFreeStmt(session->hstmt, SQL_UNBIND);
}
if((p.Id("insert") || p.Id("INSERT")) && (p.Id("into") || p.Id("INTO")) && p.IsId())
last_insert_table = p.ReadId();
if(!IsOk(SQLPrepare(session->hstmt, (SQLCHAR *)~statement, statement.GetCount())))
return false;
parse = false;
bparam = param;
param.Clear();
for(int i = 0; i < bparam.GetCount(); i++) {
Param& p = bparam[i];
SQLSMALLINT DataType;
SQLULEN ParameterSize;
SQLSMALLINT DecimalDigits;
SQLSMALLINT Nullable;
Cout() << "Direction: " << p.direction << "\n";
Cout() << "Length: " << p.li << "\n";
if(!IsOk(SQLDescribeParam(session->hstmt, i + 1, &DataType, &ParameterSize, &DecimalDigits, &Nullable)))
return false;
if(!IsOk(SQLBindParameter(session->hstmt, i + 1, p.direction, p.ctype, DataType,
ParameterSize, DecimalDigits, (SQLPOINTER)~p.data, p.data.GetLength(),
&p.li)))
return false;
}
SQLSMALLINT ncol;
if(!isStoredProcedure)
{
if(!IsOk(SQLExecute(session->hstmt)) || !IsOk(SQLNumResultCols(session->hstmt, &ncol))) {
Cout() << "SQLExecute crashed\n";
SQLFreeStmt(session->hstmt, SQL_CLOSE);
return false;
}
}
else
{
Cout() << "statement: " << statement << "\n";
if(!IsOk(SQLExecute(session->hstmt))) {
Cout() << "SQLExecute crashed\n";
SQLFreeStmt(session->hstmt, SQL_CLOSE);
return false;
}
Cout() << "Calling SQLMoreResults...\n";
//SQLFreeStmt(session->hstmt, SQL_CLOSE);
int iReturn = SQLMoreResults(session->hstmt);
Cout() << "SQLMoreResults return code: " << iReturn << "\n";
while (iReturn == SQL_SUCCESS || iReturn == SQL_SUCCESS_WITH_INFO)
{
iReturn = SQLMoreResults(session->hstmt);
} ;
//SQLFreeStmt(session->hstmt, SQL_RESET_PARAMS);
//SQLFreeStmt(session->hstmt, SQL_UNBIND);
ncol = 0;
}
session->current = this;
info.Clear();
binary.Clear();
for(int i = 1; i <= ncol; i++) {
SQLCHAR ColumnName[256];
SQLSMALLINT NameLength;
SQLSMALLINT DataType;
SQLULEN ColumnSize;
SQLSMALLINT DecimalDigits;
SQLSMALLINT Nullable;
if(!IsOk(SQLDescribeCol(session->hstmt, i, ColumnName, 255, &NameLength, &DataType,
&ColumnSize, &DecimalDigits, &Nullable)))
return false;
binary.Add(false);
SqlColumnInfo& f = info.Add();
f.nullable = Nullable != SQL_NO_NULLS;
f.binary = false;
f.precision = DecimalDigits;
f.scale = 0;
f.width = ColumnSize;
f.name = (char *)ColumnName;
switch(DataType) {
case SQL_DECIMAL:
case SQL_NUMERIC:
case SQL_SMALLINT:
case SQL_INTEGER:
case SQL_REAL:
case SQL_FLOAT:
case SQL_DOUBLE:
case SQL_BIT:
case SQL_TINYINT:
f.type = DOUBLE_V;
break;
case SQL_BIGINT:
f.type = INT64_V;
break;
case SQL_TYPE_DATE:
case SQL_TYPE_TIMESTAMP:
f.type = TIME_V;
break;
case SQL_BINARY:
case SQL_VARBINARY:
case SQL_LONGVARBINARY:
f.type = STRING_V;
f.binary = true;
binary.Top() = true;
break;
default:
f.type = STRING_V;
break;
}
}
SQLLEN rc;
SQLRowCount(session->hstmt, &rc);
rowsprocessed = rc;
return true;
}

Answer 1

Have you tried turning on SQLProfile? Maybe fire that up and watch the actual SQL hitting the database then take those SQL statements and run directly in SSMS to confirm it's doing what you expect.

Answer 2

Never mind, I was being stupid. My parameter binding was actually bound to a copy of the data and not the actual data itself. Thanks to everyone who tried to help.