OTL 4.0, Example 41(Insert/Update/Select with CLOB in Oracle 8)

Example 41 (Insert/Update/Select with CLOB in Oracle 8)

This example demonstrates INSERT, UPDATE, and SELECT statements with the CLOB datatype in Oracle 8.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
#define OTL_ORA8 // Compile OTL 4.0/OCI8
#include <otlv4.h> // include the OTL 4.0 header file

otl_connect db; // connect object

void insert()
// insert rows into table
{ 
 otl_long_string f2(70000); // define long string variable
 db.set_max_long_size(70000); // set maximum long string size for connect object

 otl_stream o(1, // buffer size has to be set to 1 for operations with LOBs
              "insert into test_tab values(:f1<int>,empty_clob()) "
              "returning f2 into :f2<clob> ",
                 // SQL statement
              db // connect object
             );
 char tmp[32];

 for(int i=1;i<=20;++i){
  for(int j=0;j<50000;++j)
   f2[j]='*';
  f2[50000]='?';
  f2.set_len(50001);
  o<<i<<f2;
 }

}
void update()
// insert rows in table
{ 
 otl_long_string f2(70000); // define long string variable
 db.set_max_long_size(70000); // set maximum long string size for connect object

 otl_stream o(1, // buffer size has to be set to 1 for operations with LOBs
              "update test_tab "
              "   set f2=empty_clob() "
              "where f1=:f1<int> "
              "returning f2 into :f2<clob> ",
                 // SQL statement
              db // connect object
             );
 char tmp[32];

 for(int j=0;j<33000;++j){
  f2[j]='#';
 }

 f2[33000]='?';
 f2.set_len(33001);

 o<<5<<f2; // update row for which f1=5

}

void select()
{ 
 otl_long_string f2(70000); // define long string variable
 db.set_max_long_size(70000); // set maximum long string size for connect object

 otl_stream i(10, // buffer size. To read CLOBs, it can be set to a size greater than 1
              "select * from test_tab where f1>=:f<int> and f1<=:f*2",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 float f1;

 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>>f1>>f2;
  cout<<"f1="<<f1<<", f2="<<f2[0]<<f2[f2.len()-1]<<", len="<<f2.len()<<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[0]<<f2[f2.len()-1]<<", len="<<f2.len()<<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 clob)"
    );  // create table

  insert(); // insert records into table
  update(); // update records in 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

f1=8, f2=*?, len=50001
f1=9, f2=*?, len=50001
f1=10, f2=*?, len=50001
f1=11, f2=*?, len=50001
f1=12, f2=*?, len=50001
f1=13, f2=*?, len=50001
f1=14, f2=*?, len=50001
f1=15, f2=*?, len=50001
f1=16, f2=*?, len=50001
f1=4, f2=*?, len=50001
f1=5, f2=#?, len=33001
f1=6, f2=*?, len=50001
f1=7, f2=*?, len=50001
f1=8, f2=*?, len=50001








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