# OTL 4.0, Example 390 (Insert/Update/Select with MS SQL Server IMAGE in stream mode, without otl_lob_stream::set_len())

This example demonstrates INSERT, UPDATE, and SELECT statements with the MS SQL Server IMAGE datatype in the stream mode without otl_lob_stream::set_len() in OTL 4.0.138 and higher.

## Source Code

    #include <iostream>
    using namespace std;

    #include <stdio.h>

    #define OTL_ODBC // Compile OTL 4.0/ODBC
    #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(6000); // define long string variable
     otl_stream o; // defined an otl_stream variable
     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 LOBs
            "insert into test_tab values(:f1<int>,:f2<raw_long>, "
            ":f3<raw_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.

     int i,j;
     otl_lob_stream lob; // LOB stream for reading/writing unlimited number
                         // of bytes regardless of the buffer size.
     otl_lob_stream lob2; // LOB stream for reading/writing unlimited number
                         // of bytes regardless of the buffer size.

     for(i=1;i<=20;++i){
      o<<i;
      o<<lob; // Initialize otl_lob_stream by writing it
              // into otl_stream.
      o<<lob2; // Initialize otl_lob_stream by writing it
              // into otl_stream.

      for(j=0;j<5000;++j)
       f2[j]='*';
      f2[5000]='?';
      f2.set_len(5001);

    // OTL 4.0.138 and higher does not require the LOB's total length to be
    // set beforehand. Instead, otl_long_string::last_piece can be used.
    //  lob.set_len(5001+2123); // setting the total  size of
    //                          // the IMAGE to be written.

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

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

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

      for(j=0;j<5000;++j)
       f2[j]='*';
      f2[5000]='?';
      f2.set_len(5001);

    // OTL 4.0.138 and higher does not require the LOB's total length to be
    // set beforehand. Instead, otl_long_string::last_piece can be used.
    //  lob2.set_len(5001+2123); // setting the total  size of
    //                          // the IMAGE to be written.

      lob2<<f2; // writing first chunk of the IMAGE into lob

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

      lob2<<f2; // writing the second chunk of the IMAGE into lob
      lob2.close(); // closing the otl_lob_stream

     }

     db.commit(); // committing transaction.
    }

    void update()
    // insert rows in table
    {

     otl_long_string f2(6200); // define long string variable

     otl_stream o; // defined an otl_stream variable
     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 LOBs
                  "update test_tab "
                  "   set f2=:f2<raw_long> "
                  "where f1=:f1<int> ",
                     // SQL statement
                  db // connect object
                 );

      otl_lob_stream lob;

      o.set_commit(0); // setting stream "auto-commit" to "off".

     for(int j=0;j<6000;++j){
      f2[j]='#';
     }

     f2[6000]='?';
     f2.set_len(6001);

     o<<lob; // Initialize otl_lob_stream by writing it
             // into otl_stream.
     o<<5;

    // lob.set_len(6001*4); // setting the total size of of the IMAGE to be written
     for(int i=1;i<=4;++i)
      lob<<f2; // writing chunks of the IMAGE into the otl_lob_stream

     lob.close(); // closing the otl_lob_stream

     db.commit(); // committing transaction

    }

    void select()
    {
     otl_long_string f2(3000); // define long string variable

     otl_stream i; // defined an otl_stream variable
     i.set_lob_stream_mode(true); // set the "lob stream mode" flag
     i.open(1, // buffer size. To read IMAGEs, it should be set to 1
                  "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 IMAGE
     otl_lob_stream lob2; // Stream for reading IMAGE

     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 LOB stream by reading the IMAGE reference
              // into the otl_lob_stream from the otl_stream.
      i>>lob2; // initializing LOB stream by reading the IMAGE reference
              // into the otl_lob_stream from the otl_stream.
      int n=0;
      while(!lob.eof()){ // read while not "end-of-file" -- end of IMAGE
       ++n;
       lob>>f2; // reading a chunk of IMAGE
       cout<<"   chunk #"<<n;
       cout<<", f2="<<f2[0]<<f2[f2.len()-1]<<", len="<<f2.len()<<endl;
      }
      lob.close(); // closing the otl_lob_stream.
      n=0;
      while(!lob2.eof()){ // read while not "end-of-file" -- end of IMAGE
       ++n;
       lob2>>f2; // reading a chunk of IMAGE
       cout<<"   chunk #"<<n;
       cout<<", f3="<<f2[0]<<f2[f2.len()-1]<<", len="<<f2.len()<<endl;
      }
      lob2.close(); // closing the otl_lob_stream.

     }

    }

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

      db.rlogon("scott/tiger@mssql"); // 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 image, f3 image)"
        );  // 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.sqlstate<<endl; // print out SQLSTATE
      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=3000
       chunk #2, f2=**, len=3000
       chunk #3, f2=*?, len=1124
       chunk #1, f3=**, len=3000
       chunk #2, f3=**, len=3000
       chunk #3, f3=*?, len=1124
    f1=5
       chunk #1, f2=##, len=3000
       chunk #2, f2=##, len=3000
       chunk #3, f2=?#, len=3000
       chunk #4, f2=##, len=3000
       chunk #5, f2=##, len=3000
       chunk #6, f2=##, len=3000
       chunk #7, f2=##, len=3000
       chunk #8, f2=##, len=3000
       chunk #9, f2=#?, len=4
       chunk #1, f3=**, len=3000
       chunk #2, f3=**, len=3000
       chunk #3, f3=*?, len=1124
    f1=6
       chunk #1, f2=**, len=3000
       chunk #2, f2=**, len=3000
       chunk #3, f2=*?, len=1124
       chunk #1, f3=**, len=3000
       chunk #2, f3=**, len=3000
       chunk #3, f3=*?, len=1124
    f1=7
       chunk #1, f2=**, len=3000
       chunk #2, f2=**, len=3000
       chunk #3, f2=*?, len=1124
       chunk #1, f3=**, len=3000
       chunk #2, f3=**, len=3000
       chunk #3, f3=*?, len=1124
    f1=8
       chunk #1, f2=**, len=3000
       chunk #2, f2=**, len=3000
       chunk #3, f2=*?, len=1124
       chunk #1, f3=**, len=3000
       chunk #2, f3=**, len=3000
       chunk #3, f3=*?, len=1124

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