#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;
}
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
Copyright © 1996-2023, 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.