OTL 4.0, Example 74 (STL std::strings, ANSI C++ typecasts, MS SQL Server)

Example 74 (STL std::strings, ANSI C++ typecasts, MS SQL Server)

This example demonstrates OTL streams and std::strings. Also, the example shows how to turn on the ANSI C++ typecasts in OTL.

Source Code

#include <iostream>
#include <string>

#define OTL_ODBC_MSSQL_2008 // Compile OTL 4/ODBC, MS SQL 2008
//#define OTL_ODBC // Compile OTL 4/ODBC. Uncomment this when used with MS SQL 7.0/ 2000
#define OTL_STL // Turn on STL features
#define OTL_ANSI_CPP // Turn on ANSI C++ typecasts

#if (defined(__clang__) || defined(__GNUC__)) && \
    (defined(OTL_CPP_14_ON) || defined(OTL_CPP_17_ON))
#include <experimental/string_view>
#define OTL_STD_STRING_VIEW_CLASS std::experimental::string_view
#define OTL_STD_STRING_VIEW_CLASS std::experimental::string_view
#elif defined(_MSC_VER) && (_MSC_VER>=1910) && defined(OTL_CPP_17_ON)
// VC++ 2017 or higher when /std=c++latest is used
#include <string_view>
#define OTL_STD_STRING_VIEW_CLASS std::string_view
#endif

#include <otlv4.h> // include the OTL 4.0 header file

using namespace std;

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
             );
 string f2;

 for(int i=1;i<=100;++i){
  f2="NameXXX";
#if defined(OTL_STD_STRING_VIEW_CLASS)
  OTL_STD_STRING_VIEW_CLASS f2_sv(f2.c_str(),f2.length());
  o<<i<<f2_sv;
#else
  o<<i<<f2;
#endif

 }
}

void select()
{ 
 otl_stream i(50, // buffer size
              "select * from test_tab where f1>=:f1<int> and f1<=:f11<int>*2",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 float f1;
 string f2;

 i<<8<<8; // assigning :f1 = 8, :f11 = 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 :f1 = 4, :f11 = 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("UID=scott;PWD=tiger;DSN=mssql2008"); // connect to ODBC

  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 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;

}

Output

f1=8, f2=NameXXX
f1=9, f2=NameXXX
f1=10, f2=NameXXX
f1=11, f2=NameXXX
f1=12, f2=NameXXX
f1=13, f2=NameXXX
f1=14, f2=NameXXX
f1=15, f2=NameXXX
f1=16, f2=NameXXX
f1=4, f2=NameXXX
f1=5, f2=NameXXX
f1=6, f2=NameXXX
f1=7, f2=NameXXX
f1=8, f2=NameXXX

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