# OTL 4.0, Example 269 (Simple Unicode Insert/Select with CLOB, and LOB streams)

# Example 269 (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. DB2SQL2 DB2 8.2 database was set to UTF-8.

## Source Code

    #include <iostream>
    using namespace std;

    #include <stdio.h>

    #define OTL_DB2_CLI // Compile OTL 4.0/Db2-CLI
    #define OTL_UNICODE // Enable Unicode OTL for DB2 CLI
    #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;

     o.set_lob_stream_mode(true); // set the "lob stream mode" flag
     o.open(1, // buffer size has to be set to 1 for operations with CLOBs
            "insert into test_tab values(:f1<int>,:f2<varchar_long>)",
               // 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;
     i.set_lob_stream_mode(true); // set the "lob stream mode" flag
     i.open(1, // buffer size needs to be set to 1 in this case
            "select * from test_tab where f1>=:f11<int> and f1<=:f12<int>*2",
               // SELECT statement
            db // connect object
           );
       // create select stream

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

     i<<4<<4; // assigning :f11 = 4, :f12 = 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 the database API environment
     try{

      db.rlogon("scott/tiger@db2sql2"); // 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 clob(1M))"
        );  // 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

    f1=4
       chunk #1, f2=**, len=5999
       chunk #2, f2=*?, len=1125
    f1=5
       chunk #1, f2=**, len=5999
       chunk #2, f2=*?, len=1125
    f1=6
       chunk #1, f2=**, len=5999
       chunk #2, f2=*?, len=1125
    f1=7
       chunk #1, f2=**, len=5999
       chunk #2, f2=*?, len=1125
    f1=8
       chunk #1, f2=**, len=5999
       chunk #2, f2=*?, len=1125

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