OTL 4.0, Example 138
(otl_stream::describe_select() with a simple Select)

Example 138 (otl_stream::describe_select() with a simple Select)

This example demonstrates the otl_stream::describe_select() with a simple SELECT statement.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
#define OTL_ODBC // Compile OTL 4.0/ FireBird Database ODBC
// #define OTL_ODBC_UNIX // uncomment this line if UnixODBC is used
#include <otlv4.h> // include the OTL 4.0 header file

otl_connect db; // connect object

void select()

 otl_stream i(10, // buffer size
              "select * from test_tab",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 otl_column_desc* desc;
 int desc_len;

 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=firebirdsql"); // connect to ODBC
//  db.rlogon("scott/tiger@firebirdsql"); // connect to ODBC, alternative format
                                    // of connect string
  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), f3 timestamp, f4 BLOB)"
    );  // create table

  db.commit(); // committing the create table statement to to the database

  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.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=4
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
========== COLUMN #3 ===========
name=F3
dbtype=93
otl_var_dbtype=8
dbsize=19
scale=0
prec=19
nullok=1
========== COLUMN #4 ===========
name=F4
dbtype=-4
otl_var_dbtype=10
dbsize=2147483647
scale=0
prec=2147483647
nullok=1


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Copyrigh6 1996-2015, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com .

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