OTL 4.0, Example 2

("Incompatible datatypes in stream operation" exception)

Example 2 ("Incompatible datatypes in stream operation" exception)

This example demonstrates a typical error in otl_stream stream operations, when datatypes of a bind variable and an actual variable in the program do not match.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>

#define OTL_ORA7 // Compile OTL 4.0/OCI7
#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<float>,:f2<char[31]>)", 
                 // SQL statement
              db // connect object
             );
 char tmp[32];

 for(int i=1;i<=100;++i){
  sprintf(tmp,"Name%d",i);
  o<<(float)i<<tmp;
 }
}

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

 i<<8; // assigning :f = 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>>f2>>f1; // a typo: f2 instead of f1
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }

 i<<4; // assigning :f = 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 OCI environment
 try{

  db.rlogon("scott/tiger"); // connect to Oracle

  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 number, f2 varchar2(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 Oracle

 return 0;

}

Output

Incompatible data types in stream operation
select * from test_tab where f1>=:f      and f1<=:f*2
Column: 1<DOUBLE>, datatype in operator <</>>: CHAR

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