在使用otl的时候,otl_stream构造函数第一个参数buffer size的使用说明.

在http://otl.sourceforge.net/otl3_stream_class.htm 中对buffer size 的说明是:The buffer size is defined in logical rows to inserted into a table, selected from a table / view in one round-trip to the database (a.k.a. batch size, array size).
为此做了如下例子进行了测试.

代码如下:

// TestOCT.cpp : Defines the entry point for the console application.
#include "stdafx.h"
#include <iostream>
using namespace std;

#include <stdio.h>
//#define OTL_ORA10G
#define OTL_ORA9I // Compile OTL 4.0/OCI9i
#define OTL_ORA_UTF8 // Enable UTF8 OTL for OCI9i
#include <otlv4.h> // include the OTL 4.0 header file
#pragma comment(lib, "oci.lib")
otl_connect db; // connect object
#define CONNECTSTRING "test/12345@192.168.1.202"

char strSql[100] = { "select f1,f2 from test_tab"};
void insert()
{
otl_stream o(3,"INSERT INTO TEST_TAB(f1,f2)values(4,'b')",db);
}
void select()
{
otl_stream o(1,strSql,db);
int count = 0;
int myf1;
char myf2[30] = {""};
while(!o.eof())
{
o>>myf1;
o>>myf2;
count++;
cout<<"f1: "<<myf1<<", f2: "<<myf2<<", 当前行数: "<<count<<endl;
}
return ;
}

int main()
{
otl_connect::otl_initialize(); // initialize OCI environment
try
{
db.rlogon(CONNECTSTRING); // connect to Oracle

otl_cursor::direct_exec(db,"drop table test_tab",otl_exception::disabled); // drop table
otl_cursor::direct_exec(db,"create table test_tab(f1 number, f2 nvarchar2(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 Oracle
return 0;
}

插入数据: otl_stream o(3,"INSERT INTO TEST_TAB(f1,f2)values(4,'b')",db);中otl_stream的构造函数的第一个 参数表示要插入的数据条数.

查询数据:otl_stream o(1,strSql,db);中otl_stream的构造函数的第一个参数表示查询到的数据从服务器传递到客户端的往返次数


执行上面的程序，得到的结果就是:

f1: 4, f2: b, 当前行数1

f1: 4, f2: b, 当前行数1

f1: 4, f2: b, 当前行数1