OTL 4.0, Example 225 (Simple Insert/Select/Update, MyODBC 3.50)

Example 225 (Simple Insert/Select/Update, MyODBC 3.50)

This example demonstrates simple INSERT, SELECT, UPDATE and constant SQL statements. This example works with MySQL via MyODBC 3.5. Pay attention to the restrictions [imposed by MyODBC] on the use of the OTL classes.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define OTL_ODBC // Compile OTL 4.0/ODBC
// The following #define is required with MyODBC 3.51.11 and higher
#define OTL_ODBC_SELECT_STM_EXECUTE_BEFORE_DESCRIBE
// #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(1, // buffer size should be == 1 always on INSERT
"insert into test_tab values "
" (:f1<int>,:f2<char[31]>), "
" (:f12<int>,:f22<char[31]>), "
" (:f13<int>,:f23<char[31]>), "
" (:f14<int>,:f24<char[31]>), "
" (:f15<int>,:f25<char[31]>) ",
// INSERT statement. Multiple sets of values can be used
// to work around the lack of the bulk interface
db // connect object
);

// If the number of rows to be inserted is not known in advance,
// another stream with the same INSERT can be opened
 otl_stream o2(1, // buffer size should be == 1 always on INSERT
"insert into test_tab values "
" (:f1<int>,:f2<char[31]>)",
db // connect object
);

 char tmp[32];
int i;
 for(i=1;i<=100;++i){
  sprintf(tmp,"Name%d",i);
  o<<i<<tmp;
 }
 for(i=101;i<=103;++i){
  sprintf(tmp,"Name%d",i);
  o2<<i<<tmp;
 }
}
void update(const int af1)
// insert rows into table

 otl_stream o(1, // buffer size should be == 1 always on UPDATE
              "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

}
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; // :f11 = af1, :f12 = af1

#if (defined(_MSC_VER) && _MSC_VER>=1600) || defined(OTL_CPP_11_ON)
// C++11 (or higher) compiler
for(auto& it : i){
it>>f1;
cout<<"f1="<<f1<<", f2=";
it>>f2;
if(it.is_null())
cout<<"NULL";
else
cout<<f2;
cout<<endl;
}
#else
// C++98/03 compiler
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;
}
#endif

}

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

  db.rlogon("UID=scott;PWD=tiger;DSN=mysql35"); // connect to ODBC
//  db.rlogon("scott/tiger@mysql35"); // connect to ODBC, alternative format
                                    // of connect string 

  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)) type=innoDB"
    );  // 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 ODBC

 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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Copyright 1996-2017, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com .

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