OTL 4.0, Example 33
(MS SQL Server: otl_stream::describe_select() and result sets)

Example 33 (MS SQL Server: otl_stream::describe_select() and result sets)

This example demonstrates the otl_stream::describe_select() with a stored procedure call returning a result set.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>

#define OTL_ODBC_MSSQL_2005 // Compile OTL 4/ODBC, MS SQL 2005
//#define OTL_ODBC // Compile OTL 4/ODBC. Uncomment this when used with MS SQL 7.0/ 2000
#include <otlv4.h> // include the OTL 4.0 header file

otl_connect db; // connect object

void insert()
// insert rows into table
{ 
 otl_stream o(50, // buffer size
              "insert into test_tab values(:f1<float>,:f2<char[31]>)", 
                 // SQL statement
              db // connect object
             );
 char tmp[32];

 for(int i=1;i<=100;++i){
  sprintf(tmp,"Name%d",i);
  o<<(float)i<<tmp;
 }
}

void select()
{ 
 otl_stream i(50, // buffer size
              "{call my_proc(:f1<int>)}", // SELECT statement via stored procedure
              db, // connect object
              otl_implicit_select // implicit SELECT statement
             ); 
   // create select stream
 
 otl_column_desc* desc;
 int desc_len;

 i<<4; // Before the child SELECT statement can be described,
       // the stored procedure needs to be executed.
       // Forcing the execution of the stored procedure by entering its input 
       // patameter.

 desc=i.describe_select(desc_len);

 for(int n=0;n<desc_len;++n){
  cout<<"========== COLUMN #"<<n+1<<" ==========="<<endl;
  cout<<"name="<<desc[n].name<<endl;
  cout<<"dbtype="<<desc[n].dbtype<<endl;
  cout<<"otl_var_dbtype="<<desc[n].otl_var_dbtype<<endl;
  cout<<"dbsize="<<desc[n].dbsize<<endl;
  cout<<"scale="<<desc[n].scale<<endl;
  cout<<"prec="<<desc[n].prec<<endl;
  cout<<"nullok="<<desc[n].nullok<<endl;
 }
 

}

int main()
{
 otl_connect::otl_initialize(); // initialize ODBC environment
 try{

  db.rlogon("uid=scott;pwd=tiger;dsn=mssql2008"); // connect to ODBC

  otl_cursor::direct_exec
   (
    db,
    "drop table test_tab",
    otl_exception::disabled // disable OTL exceptions
   ); // drop table

  otl_cursor::direct_exec
   (
    db,
    "create table test_tab(f1 int, f2 varchar(30))"
    );  // create table

  otl_cursor::direct_exec
   (
    db,
    "CREATE PROCEDURE my_proc "
    "  @F1 int "
    "AS "
    "SELECT * FROM test_tab "
    "WHERE f1>=@F1 AND f1<=@F1*2 "
    );  // create stored procedure

  insert(); // insert record into table
  select(); // select records from table

 }

 catch(otl_exception& p){ // intercept OTL exceptions
  cerr<<p.msg<<endl; // print out error message
  cerr<<p.stm_text<<endl; // print out SQL that caused the error
  cerr<<p.sqlstate<<endl; // print out SQLSTATE message
  cerr<<p.var_info<<endl; // print out the variable that caused the error
 }

 db.logoff(); // disconnect from ODBC

 return 0;

}

Output

========== COLUMN #1 ===========
name=f1
dbtype=4
otl_var_dbtype=2
dbsize=10
scale=0
prec=10
nullok=1
========== COLUMN #2 ===========
name=f2
dbtype=12
otl_var_dbtype=1
dbsize=30
scale=0
prec=30
nullok=1

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