OTL 4.0, Example 713 (END-OF-ROW check)

This example demonstrates how to use the "end-of-row" function / stream manipulators with SELECT and INSERT statements.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
#define OTL_ODBC_MSSQL_2008 // Compile OTL 4.0/MS SQL 2008
#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
"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<<endr; // OTL stream manipulator "endr" checks
// the "end of row" condition. As time goes on,
// the table layout may change, and the end-of-row check
// may throw an exception if the end-of-row condition
// fails.
}
o.flush(); // flush the stream dirty buffer
// example of a faied end-of-row condition
try{
o<<i;
// input for bind variable :f2 is missing
o<<endr; // this will throw an exception
}catch(otl_exception& p){
o.clean(1); // reset the stream state
cerr<<"ERROR CODE="<<p.msg<<endl; // print out error message
cerr<<"ERROR SQL STM="<<p.stm_text<<endl; // print out SQL that caused the error
cerr<<"ERROR VAR INFO="<<p.var_info<<endl; // print out the variable that caused the error
}
}

void select()
{
otl_stream i(50, // buffer size
"select * from test_tab where f1>=:f_1<int><int> and f1<=:f_2<int>*2",
// SELECT statement
db // connect object
);
// create select stream

int f1;
char f2[31];

i<<8; // assigning :f_1 = 8, :f_2 = 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>>endr; // endr checks the end-of-row condition. As times goes on,
// The output column list on the SELECT statement may change,
// and the endr check may an exception.
cout<<"f1="<<f1<<", f2="<<f2<<endl;
}

i<<4; // assigning :f_1 = 4, :f_2 = 4
// SELECT automatically executes when all input variables are
// assigned. First portion of output rows is fetched to the buffer
try{
// example of a failed end-of-row check
while(!i.eof()){ // while not end-of-data
i>>f1;
// reading of the f2 output column is missing
i>>endr; // this will throw an exception
cout<<"f1="<<f1<<", f2="<<f2<<endl;
}
}catch(otl_exception& p){
cerr<<"ERROR CODE (SELECT) ="<<p.msg<<endl; // print out error message
cerr<<"ERROR SQL STM (SELECT) ="<<p.stm_text<<endl; // print out SQL that caused the error
cerr<<"ERROR VAR INFO (SELECT) ="<<p.var_info<<endl; // print out the variable that caused the error
}

}

int main()
{
otl_connect::otl_initialize(); // initialize the database API
try{

db.rlogon("scott/tiger@mssql2008"); // 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 varchar(30))"
); // 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;

}

Output

ERROR CODE=END-OF-ROW check failed
ERROR SQL STM=insert into test_tab values(:f1 ,:f2 )
ERROR VAR INFO=
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
ERROR CODE (SELECT) =END-OF-ROW check failed
ERROR SQL STM (SELECT) =select * from test_tab where f1>=:f and f1<=:f*2
ERROR VAR INFO (SELECT) =



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