OTL 4.0, Example 342 (OTL stream read iterator, "get by name" functions, PostgreSQL)

This example demonstrates otl_stream_read_iterator for PostgreSQL

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
// #define OTL_ODBC_UNIX // uncomment this line if UnixODBC is used
#define OTL_ODBC_ALTERNATE_RPC
#if !defined(_WIN32) && !defined(_WIN64)
#define OTL_ODBC
#else
#define OTL_ODBC_POSTGRESQL // required with PG ODBC on Windows
#endif

#define OTL_STL
#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_stream o(50, // buffer size can be > 1 in PostgreSQL 8.1 and higher
"insert into test_tab values(:f1<int>,:f2<char[31]>)",
// SQL statement
db // connect object
);
char tmp[32];

for(int i=1;i<=100;++i){
sprintf(tmp,"Name%d",i);
o<<i<<tmp;
}
}

void select()
{
otl_stream i(50, // buffer size
"select * from test_tab "
"where f1>=:f11<int> and f1<=:f12<int>*2",
// SELECT statement
db // connect object
);
// create select stream

int f1;
char f2[31];
otl_stream_read_iterator<otl_stream,otl_exception,otl_lob_stream> rs;

i<<8<<8; // assigning :f11 = 8, :f12 = 8
// SELECT automatically executes when all input variables are
// assigned. First portion of output rows is fetched to the buffer

rs.attach(i); // attach the iterator "rs" to the stream "i".

#if (defined(_MSC_VER) && _MSC_VER>=1600) || defined(OTL_CPP_11_ON)
// C++11 (or higher) compiler
for(auto& it : rs){
it.get("F1",f1);
it.get("F2",f2);
cout<<"f1="<<f1<<", f2="<<f2<<endl;
}
#else
// C++98/03 compiler
while(rs.next_row()){ // while not end-of-data
rs.get("F1",f1);
rs.get("F2",f2);
cout<<"f1="<<f1<<", f2="<<f2<<endl;
}
#endif

rs.detach(); // detach the itertor from the stream

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>>f2;
cout<<"f1="<<f1<<", f2="<<f2<<endl;
}

}

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

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

otl_cursor::direct_exec
(
db,
"drop table test_tab",
otl_exception::disabled // disable OTL exceptions
); // drop table
db.commit();
otl_cursor::direct_exec
(
db,
"create table test_tab(f1 int, f2 varchar(30))"
); // create table
db.commit();
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 ODBC

return 0;

}

Output

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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Copyright 1996-2017, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com/a>.

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