OTL 4.0, Example 378 (Insert/Update/Select with Oracle 8i/9i/10g CLOB in stream mode and stored procs)

This example demonstrates PL/SQL (stored procs) INSERT, UPDATE, and SELECT statements with the Oracle 8i/9i/10g CLOB datatype in stream mode.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
#define OTL_ORA8I // Compile OTL 4.0/OCI8i
//#define OTL_ORA9I // Compile OTL 4.0/OCI9i
//#define OTL_ORA10G // Compile OTL 4.0/OCI10g
//#define OTL_ORA10G_R2 // Compile OTL 4.0/OCI10g Release 2
#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(5000); // define long string variable
otl_stream o(1, // buffer size has to be set to 1 for operations with LOBs
"begin "
" insert_proc(:f1<int,in>,:f2<clob,in>); "
"end;", // PL/SQL block that calls a stored procedure.
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.

for(int i=1; i<=3; ++i){
for(int j=0;j<4000;++j)
f2[j]='*';
f2[4000]='?';
f2.set_len(4001);
o<<i;
o<<lob; // Initialize otl_lob_stream by writing it into the otl_stream
lob.set_len(4001); // setting the total size of of the CLOB to be written
lob<<f2; // writing f2 into lob
lob.close(); // closing the otl_lob_stream
}
db.commit(); // committing transaction.
}
void update()
// insert rows in table
{
 otl_long_string f2(5200); // define long string variable

otl_stream o(1, // buffer size has to be set to 1 for operations with LOBs
"begin "
" update_proc(:f1<int,in>,:f2<clob,in>); "
"end;", // PL/SQL block that calls a stored procedure
db // connect object
);

otl_lob_stream lob;

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


for(int j=0;j<5000;++j){
f2[j]='#';
}
f2[5000]='?';
f2.set_len(5001);
o<<2;
o<<lob; // Initialize otl_lob_stream by writing it
// into otl_stream.
lob.set_len(5001*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(int f1)
{
otl_long_string f2(6000); // define long string variable

otl_stream i(1, // buffer size needs to be set to 1
"begin "
" select_proc(:f1<int,in>,:f2<clob,out>); "
"end;", // PL/SQL block that calls a stored procedure
db // connect object
);

otl_lob_stream lob; // Stream for reading CLOB

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="<<f2[0]<<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<<"scott/tiger"; // connect to the database

// Send SQL statements to the connect obejct for immediate execution.
// Ignore any exception for the first statement.
try{ db<<"drop table test_tab"; } catch(otl_exception&){}
db<<"create table test_tab(f1 int, f2 clob)";
db<<"CREATE OR REPLACE PROCEDURE insert_proc "
" (A in NUMBER, "
" B in out nocopy CLOB) "
"IS "
"BEGIN "
" insert into TEST_TAB (F1, F2) "
" values (a, EMPTY_CLOB()) "
" returning F2 into B; "
"END;";
db<<"CREATE OR REPLACE PROCEDURE update_proc "
" (A in NUMBER, "
" B in out nocopy CLOB) "
"IS "
"BEGIN "
" select F2 "
" into B "
" from TEST_TAB "
" where F1 = A "
" for update nowait; "
"END;";
db<<"CREATE OR REPLACE PROCEDURE select_proc "
" (A in NUMBER, "
" B in out nocopy CLOB) "
"IS "
"BEGIN "
" select F2 "
" into B "
" from TEST_TAB "
" where f1 = A; "
"END;";
insert(); // insert records into table
update(); // update records in table
select(1); // select records from table
select(2); // select records from table
select(3); // 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=1
chunk #1, f2=*?, len=4001
f1=2
chunk #1, f2=##, len=6000
chunk #2, f2=##, len=6000
chunk #3, f2=##, len=6000
chunk #4, f2=#?, len=2004
f1=3
chunk #1, f2=*?, len=4001

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Copyright © 1996-2017, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com .

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