ex573_odbc.cpp

来自「一个跨平台的数据库操作库文件,可以轻松在linux和windows下进行数据库读」· C++ 代码 · 共 75 行

#include <iostream>
#include <stdio.h>
using namespace std;

#define OTL_ODBC
//#define OTL_ODBC_UNIX // Compile OTL 4.0/ODBC
#include <otlv4.h> // include the OTL 4.0 header file


otl_connect db; // connect object


void select()
{ 
 otl_stream s;

 s.set_all_column_types(otl_all_num2str|otl_all_date2str); 
    // map all numeric and date/time output columns to strings for simplicity.

 db.auto_commit_on(); // setting database connect auto-commit to ON

 s.open(100, // buffer size
         "$SQLColumns $1:'sybsql' $2:'scott' $3:'test_tab'",
         //  get a list of all columns of table 
         // "test_tab" that belongs to schema "dbo", 
         // catalog "sybsql"
         db // connect object
        ); 

 otl_column_desc* desc;
 int desc_len;
 desc=s.describe_select(desc_len); 
    // describe the structure of the output columns of the result set.

 int rpc=0;
 while(!s.eof()){
   ++rpc;
   char str[512];
   cout<<"ROW#"<<rpc<<" ";
   for(int col_num=0;col_num<desc_len;++col_num){
     s>>str;
     if(s.is_null())
       cout<<desc[col_num].name<<"=NULL ";
     else
       cout<<desc[col_num].name<<"="<<str<<" ";
   }
   cout<<endl;
 }

}

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

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

  select(); // query the system data dictionary via ODBC functions.

 }

 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;

}