ex284_odbc.cpp

使用otl开发的数据库应用包

#include <iostream>
using namespace std;

#include <stdio.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 is
                       // not up to the ODBC 3.5 level just yet
#define OTL_ADD_NULL_TERMINATOR_TO_STRING_SIZE
#include <otlv4.h> // include the OTL 4.0 header file

otl_connect db; // connect object

void insert()
// insert rows into table
{ 
 // open a stream with no implicit committing
 otl_nocommit_stream 
    o(10, // buffer size
      "insert into test_tab values(:f1<int>,:f2<char[2]>)", 
         // SQL statement
      db // connect object
     );
 otl_cursor::direct_exec(db,"BEGIN TRANSACTION");
    // begin transaction. This explicit construct needs to be used 
    // because the ODBC driver could eventually run into the 
    // "Function Sequence Error" error.
 for(int i=1;i<=100;++i){
  o<<i<<"AB";
 }
 o.flush(); // flush the stream buffer to make sure that 
            // all rows get to the table
 otl_cursor::direct_exec(db,"COMMIT TRANSACTION");
    // commit transaction
}

void select()
{ 
 otl_stream i(50, // buffer size
              "select * from test_tab where f1>=:f<int> and f1<=:ff<int>*2",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 float f1;
 char f2[31];

 i<<8<<8; // assigning :f = 8; :ff = 8
   // 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;
 }

 i<<4<<4; // assigning :f = 4, :ff = 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/tiger@sqlite",1);
    // connect to the database and set the auto-commit to on. 
    // The auto-commit is needed to make "BEGIN TRANSACTION" / 
    // "COMMIT TRANSACTION" work properly.

  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(2))"
    );  // create table

  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.sqlstate<<endl; // print out SQLSTATE message
  cerr<<p.var_info<<endl; // print out the variable that caused the error
 }

 db.logoff(); // disconnect from Oracle

 return 0;

}