OTL 4.0, Example 117 (otl_stream::set_flush(), OTL/ODBC)

Example 117 (otl_stream::set_flush(), OTL/ODBC)

This example demonstrates the otl_stream::set_flush() function.

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 insert1()
// insert rows into table
{
otl_stream o; // define an otl_stream variable

o.set_flush(false); // set the auto-flush flag to OFF.

o.open(200, // buffer size
"insert into test_tab values(:f1<float>,:f2<char[31]>)",
// SQL statement
db // connect object
);
char tmp[32];

for(int i=1;i<=100;++i){
sprintf(tmp,"Name%d",i);
o<<(float)i<<tmp;
if(i%55==0)
throw "Throwing an exception";
}
o.flush(); // when the auto-flush flag is OFF, an explicit flush
// of the stream buffer is required in case of successful
// completion of execution of the INSERT statement.
// In case of a raised exception, the stream buffer would not be flushed.
}

void insert2()
// insert rows into table
{
otl_stream o; // define an otl_stream variable

o.set_flush(false); // set the auto-flush flag to OFF.

o.open(200, // buffer size
"insert into test_tab values(:f1<float>,:f2<char[31]>)",
// SQL statement
db // connect object
);
char tmp[32];

for(int i=1;i<=100;++i){
sprintf(tmp,"Name%d",i);
o<<(float)i<<tmp;
// if(i%55==0)
// throw "Throwing an exception";
}
o.flush(); // when the auto-flush flag is OFF, an explicit flush
// of the stream buffer is required in case of successful
// completion of execution of the INSERT statement.
// In case of a raised exception, the stream buffer would not be flushed.
}

void select()
{
otl_stream i(50, // buffer size
"select * from test_tab where f1>=:f<int> and f1<=:ff<int>*2",
// SELECT statement
db // connect object
);
// create select stream

float f1;
char f2[31];

i<<8<<8; // assigning :f = 8, :ff = 8
// 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>>f2;
cout<<"f1="<<f1<<", f2="<<f2<<endl;
}

i<<4<<4; // assigning :f = 4, :ff = 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>>f2;
cout<<"f1="<<f1<<", f2="<<f2<<endl;
}

}

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

db.rlogon("scott/tiger@mssql"); // connect to ODBC

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 varchar(30))"
); // create table

try{
insert1(); // insert records into table
}catch(const char* p){
cout<<p<<endl;
}
cout<<"Selecting the first time around:"<<endl;
select(); // select records from table

insert2();
cout<<"Selecting the second time around:"<<endl;
select();

}

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 ODBC

return 0;

}

Output

Throwing an exception
Selecting the first time around:
Selecting the second time around:
f1=8, f2=Name8
f1=9, f2=Name9
f1=10, f2=Name10
f1=11, f2=Name11
f1=12, f2=Name12
f1=13, f2=Name13
f1=14, f2=Name14
f1=15, f2=Name15
f1=16, f2=Name16
f1=4, f2=Name4
f1=5, f2=Name5
f1=6, f2=Name6
f1=7, f2=Name7
f1=8, f2=Name8








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