# OTL 4.0, Example 182 (Simple Unicode Insert/Select with CLOB, and LOB streams)

# Example 182 (Simple Unicode Insert/Select with CLOB, and LOB streams)

This example demonstrates simple Unicode INSERT, SELECT, and constant SQL statements with CLOB columns, and LOB streams

## Source Code

    #include <iostream>
    using namespace std;

    #include <stdio.h>

    #define OTL_ORA8I // Compile OTL 4.0/OCI8i
    #define OTL_UNICODE // Enable Unicode OTL for OCI8i
    #include <otlv4.h> // include the OTL 4.0 header file

    otl_connect db; // connect object

    void insert()
    // insert rows into table
    {
     otl_long_unicode_string f2(6000); // define long unicode string variable

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

     o.set_commit(0); // setting stream "auto-commit" to "off". It is required
                      // when LOB stream mode is used.

     otl_lob_stream lob; // LOB stream for reading/writing unlimited number
                         // of bytes regardless of the buffer size.

     int i,j;

     for(i=1;i<=20;++i){
      o<<i;
      o<<lob; // Initialize otl_lob_stream by writing it
              // into otl_stream.

      for(j=0;j<5000;++j)
       f2[j]=(unsigned short) '*'; // ASCII to Unicode.
      f2[5000]= (unsigned short) '?'; // ASCII to Unicode
      f2.set_len(5001);

      lob.set_len(5001+2123); // setting the total  size of
                              // the CLOB to be written.

      lob<<f2; // writing first chunk of the CLOB into lob

      f2[2122]= (unsigned short) '?';
      f2.set_len(2123); // setting the size of the second chunk

      lob<<f2; // writing the second chunk of the CLOB into lob
      lob.close(); // closing the otl_lob_stream

     }

     db.commit(); // committing transaction.

    }

    void select()
    {
     otl_long_unicode_string f2(6000); // define Unicode long string variable

     otl_stream i(10, // buffer size
                  "select * from test_tab where f1>=:f<int> and f1<=:f*2",
                     // SELECT statement
                  db // connect object
                 );
       // create select stream

     float f1;
     otl_lob_stream lob; // Stream for reading CLOB

     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;
      cout<<"f1="<<f1<<endl;
      i>>lob; // initializing CLOB stream by reading the CLOB reference
              // into the otl_lob_stream from the otl_stream.
      int n=0;
      while(!lob.eof()){ // read while not "end-of-file" -- end of CLOB
       ++n;
       lob>>f2; // reading a chunk of CLOB
       cout<<"   chunk #"<<n;
       cout<<", f2="
           <<(char)f2[0] // Unicode to ASCII
           <<(char)f2[f2.len()-1]<<", len="<<f2.len()<<endl;
      }
      lob.close(); // closing the otl_lob_stream. This step may be skipped.
     }
    }

    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
      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=4
       chunk #1, f2=**, len=6000
       chunk #2, f2=*?, len=1124
    f1=5
       chunk #1, f2=**, len=6000
       chunk #2, f2=*?, len=1124
    f1=6
       chunk #1, f2=**, len=6000
       chunk #2, f2=*?, len=1124
    f1=7
       chunk #1, f2=**, len=6000
       chunk #2, f2=*?, len=1124
    f1=8
       chunk #1, f2=**, len=6000
       chunk #2, f2=*?, len=1124

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Copyright © 1996, 2007, Sergei Kuchin, email: skuchin@ispwest.com, skuchin@gmail.com
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