OTL 4.0, Example 713 (END-OF-ROW check)

This example demonstrates how to use the "end-of-row" function / stream manipulators with SELECT and INSERT statements.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>

#define OTL_ODBC_MSSQL_2008 // Compile OTL 4.0/MS SQL 2008
#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){
  sprintf(tmp,"Name%d",i);
  o<<i<<tmp<<endr; // OTL stream manipulator "endr" checks 
                   // the "end of row" condition. As time goes on,
                   // the table layout may change, and the end-of-row check
                   // may throw an exception if the end-of-row condition
                   // fails.
 }
 o.flush(); // flush the stream dirty buffer
 // example of a faied end-of-row condition
 try{
  o<<i;
  // input for bind variable :f2 is missing
  o<<endr; // this will throw an exception
 }catch(otl_exception& p){
  o.clean(1); // reset the stream state
  cerr<<"ERROR CODE="<<p.msg<<endl; // print out error message
  cerr<<"ERROR SQL STM="<<p.stm_text<<endl; // print out SQL that caused the error
  cerr<<"ERROR VAR INFO="<<p.var_info<<endl; // print out the variable that caused the error
 }
}

void select()
{ 
 otl_stream i(50, // buffer size
              "select * from test_tab where f1>=:f_1<int><int> and f1<=:f_2<int>*2",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 int f1;
 char f2[31];

 i<<8; // assigning :f_1 = 8, :f_2 = 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>>endr; // endr checks the end-of-row condition. As times goes on,
                   // The output column list on the SELECT statement may change,
                   // and the endr check may an exception.
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }

 i<<4; // assigning :f_1 = 4, :f_2 = 4 
   // SELECT automatically executes when all input variables are
   // assigned. First portion of output rows is fetched to the buffer
 try{
// example of a failed end-of-row check
   while(!i.eof()){ // while not end-of-data
    i>>f1;
    // reading of the f2 output column is missing
    i>>endr; // this will throw an exception
    cout<<"f1="<<f1<<", f2="<<f2<<endl;
   }
 }catch(otl_exception& p){
  cerr<<"ERROR CODE (SELECT) ="<<p.msg<<endl; // print out error message
  cerr<<"ERROR SQL STM (SELECT) ="<<p.stm_text<<endl; // print out SQL that caused the error
  cerr<<"ERROR VAR INFO (SELECT) ="<<p.var_info<<endl; // print out the variable that caused the error
 }

}

int main()
{
 otl_connect::otl_initialize(); // initialize the database API
 try{

  db.rlogon("scott/tiger@mssql2008"); // connect to the database

  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 the database

 return 0;

}

Output

ERROR CODE=END-OF-ROW check failed
ERROR SQL STM=insert into test_tab values(:f1     ,:f2          )
ERROR VAR INFO=
f1=8, f2=Name8
f1=9, f2=Name9
f1=10, f2=Name10
f1=11, f2=Name11
f1=12, f2=Name12
f1=13, f2=Name13
f1=14, f2=Name14
f1=15, f2=Name15
f1=16, f2=Name16
ERROR CODE (SELECT) =END-OF-ROW check failed
ERROR SQL STM (SELECT) =select * from test_tab where f1>=:f      and f1<=:f*2
ERROR VAR INFO (SELECT) =

Examples Contents Go Home

Permission to use, copy, modify and redistribute this document for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.