ex579_odbc.cpp

otl编程的举例

#include <iostream>
using namespace std;

#include <stdio.h>

#define OTL_ODBC
//#define OTL_ODBC_UNIX // Compile OTL 4.0/ODBC
#define OTL_STREAM_READ_ITERATOR_ON
#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<int>,:f2<char[31]>)", 
                 // SQL statement
              db // connect object
             );
 char tmp[32];

 for(int i=1;i<=100;++i){
#if defined(_MSC_VER)
#if (_MSC_VER >= 1400) // VC++ 8.0 or higher
  sprintf_s(tmp,sizeof(tmp),"Name%d",i);
#else
  sprintf(tmp,"Name%d",i);
#endif
#else
  sprintf(tmp,"Name%d",i);
#endif
  o<<i<<tmp;
 }
}

void select()
{ 
 otl_stream i(50, // buffer size
              "{call my_proc(:f1<int,in>)}",
                 // implicit SELECT statement
              db, // connect object
              otl_implicit_select // implicit SELECT statement
             ); 
   // create select stream
 
 int f1;
 char f2[31];
otl_stream_read_iterator<otl_stream,otl_exception,otl_lob_stream> rs;

 i<<8; // assigning :f1 = 8
   // SELECT automatically executes when all input variables are
   // assigned. First portion of output rows is fetched to the buffer

 rs.attach(i); // attach the iterator "rs" to the stream "i".

 while(rs.next_row()){ // while not end-of-data
  rs.get(1,f1);
  rs.get(2,f2);
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }

 rs.detach(); // detach the itertor from the stream

 i<<4; // assigning :f1 = 4
   // SELECT automatically executes when all input variables are
   // assigned. First portion of output rows is fetched to the buffer

 while(!i.eof()){ // while not end-of-data
  i>>f1>>f2;
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }

}

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

  db.rlogon("scott/tigger@freetds_sybsql"); // connect to ODBC
  db.auto_commit_off();

  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,
    "DROP PROCEDURE my_proc",
    0 // ignore any errors
    );  // drop stored procedure

  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 records 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.var_info<<endl; // print out the variable that caused the error
 }

 db.logoff(); // disconnect from ODBC

 return 0;

}