#include <iostream>
using namespace std;
#include <stdio.h>
#define OTL_DB2_CLI // Compile OTL 4.0/DB2-CLI
#define OTL_STREAM_READ_ITERATOR_ON
#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<varchar_long>, "
":f3<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.
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);
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]='?';
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
for(j=0;j<5000;++j)
f2[j]='*';
f2[5000]='?';
f2.set_len(5001);
lob2.set_len(5001+2123); // setting the total size of
// the CLOB to be written.
lob2<<f2; // writing first chunk of the CLOB into lob
f2[2122]='?';
f2.set_len(2123); // setting the size of the second chunk
lob2<<f2; // writing the second chunk of the CLOb 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<varchar_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 CLOB to be written
for(int i=1;i<=4;++i)
lob<<f2; // writing chunks of the CLOB 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;
i.set_lob_stream_mode(true); // set the "lob stream mode" flag
i.open(1, // buffer size. To read CLOB, it needs to 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; // Pointer to Stream for reading CLOB
otl_lob_stream* lob2; // Pointer to Stream for reading CLOb
otl_stream_read_iterator<otl_stream,otl_exception,otl_lob_stream> rs;
rs.attach(i); // attach the iterator "rs" to the stream "i".
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(rs.next_row()){ // while not end-of-data
rs.get(1,f1);
cout<<"f1="<<f1<<endl;
rs.get(2,lob); // get pointer to LOB stream
rs.get(3,lob2); // get pointer to LOB 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="<<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 CLOB
++n;
(*lob2)>>f2; // reading a chunk of CLOB
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@db2sql"); // 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(2M), f3 clob(2M))"
); // 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;
}
f1=4
chunk #1, f2=**, len=2999
chunk #2, f2=**, len=2999
chunk #3, f2=*?, len=1126
chunk #1, f3=**, len=2999
chunk #2, f3=**, len=2999
chunk #3, f3=*?, len=1126
f1=5
chunk #1, f2=##, len=2999
chunk #2, f2=##, len=2999
chunk #3, f2=##, len=2999
chunk #4, f2=##, len=2999
chunk #5, f2=##, len=2999
chunk #6, f2=##, len=2999
chunk #7, f2=##, len=2999
chunk #8, f2=##, len=2999
chunk #9, f2=#?, len=12
chunk #1, f3=**, len=2999
chunk #2, f3=**, len=2999
chunk #3, f3=*?, len=1126
f1=6
chunk #1, f2=**, len=2999
chunk #2, f2=**, len=2999
chunk #3, f2=*?, len=1126
chunk #1, f3=**, len=2999
chunk #2, f3=**, len=2999
chunk #3, f3=*?, len=1126
f1=7
chunk #1, f2=**, len=2999
chunk #2, f2=**, len=2999
chunk #3, f2=*?, len=1126
chunk #1, f3=**, len=2999
chunk #2, f3=**, len=2999
chunk #3, f3=*?, len=1126
f1=8
chunk #1, f2=**, len=2999
chunk #2, f2=**, len=2999
chunk #3, f2=*?, len=1126
chunk #1, f3=**, len=2999
chunk #2, f3=**, len=2999
chunk #3, f3=*?, len=1126
Copyright © 1996-2024, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com .
Permission to use, copy, modify and redistribute this document for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.