OTL 4.0, Example 277 (Simple Insert/Select/Update)

This example demonstrates simple INSERT, SELECT, UPDATE and constant SQL statements.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define OTL_ODBC // Compile OTL 4.0/ODBC
#define ODBCVER 0x0250 // ODBC Version # needs to be downgraded
                       // to 2.5 because the SQLite ODBC driver seems
                       // to run slower when ODBC 3.x functions
                       // used (performance is not as good as with
                       // ODBC 2.5 function calls)
// #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 insert()
// insert rows into table
{ 
 otl_stream
    o(50, // stream buffer size
      "insert into test_tab values(:f1<int>,:f2<char[31]>)", 
          // SQL statement
      db  // connect object
     );
 char tmp[32];
 for(int i=1;i<=100;++i){
  sprintf(tmp,"Name%d",i);
  o<<i<<tmp;
 }
}

void update(const int af1)
// insert rows into table
{
 otl_stream 
   o(1, // buffer size
     "UPDATE test_tab "
     "   SET f2=:f2<char[31]> "
     " WHERE f1=:f1<int>", 
        // UPDATE statement
     db // connect object
    );

 o<<"Name changed"<<af1;
 o<<otl_null()<<af1+1; // set f2 to NULL
 // there is no need to flush the stream buffer here 
 // because the buffer size is 1: the stream flushes 
 // the buffer every time the buffer gets full
}

void select(const int af1)
{ 
 otl_stream i(50, // buffer size may be > 1
              "select * from test_tab "
              "where f1>=:f11<int> "
              "  and f1<=:f12<int>*2", 
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 int f1;
 char f2[31];

 i<<af1<<af1; // Writing input values into the stream
 while(!i.eof()){ // while not end-of-data
  i>>f1;
  cout<<"f1="<<f1<<", f2=";
  i>>f2;
  if(i.is_null())
   cout<<"NULL";
  else
   cout<<f2;
  cout<<endl;
 }

}

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

  db.rlogon("scott/tiger@sqlite"); 

  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

  insert(); // insert records into the table
  update(10); // update records in the table
  select(8); // select records from the 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 the database

 return 0;

}

Output

f1=8, f2=Name8
f1=9, f2=Name9
f1=10, f2=Name changed
f1=11, f2=NULL
f1=12, f2=Name12
f1=13, f2=Name13
f1=14, f2=Name14
f1=15, f2=Name15
f1=16, f2=Name16

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