Viewing file:  CLOBREAD.CPP (1.44 KB) -rw-rw-rw-
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#include <oracl.h>
#include <iostream.h>
#include <fstream.h>
// Example for OClob::Read
int main()
{
//Initialize oo4o, connect, execute sql
OStartup();
ODatabase odb("ExampleDB", "scott", "tiger");
ODynaset odyn(odb, "SELECT * FROM PART");
if (!odyn.IsOpen())
{
cout <<"Connect Error: "<<odb.GetErrorText()<<endl;
cout <<"SQL Error: "<<odyn.GetErrorText()<<endl;
return 1;
}
OClob oclob;
odyn.GetFieldValue("PART_DESC", &oclob);
unsigned char *buffer = 0;
try
{
fstream fs;
fs.open("descout.txt", ios::out);
fs.setmode(filebuf::binary);
unsigned long size = oclob.GetSize();
// calculate an optimum buffersize of approximately 32k bytes
unsigned long optchunk = oclob.GetOptimumChunkSize();
unsigned int bufsize = ((int)(32768/optchunk)) *optchunk;
if (bufsize > size)
bufsize = size;
buffer = (unsigned char *)malloc(bufsize);
//By taking advantage of streaming we get the best performance
//and do not need to allocate a large buffer
oclob.EnableStreaming(size);
short status= OLOB_NEED_DATA;
unsigned long amtread=0;
while(status == OLOB_NEED_DATA)
{
amtread = oclob.Read(&status, buffer, bufsize);
fs.write(buffer, amtread);
}
oclob.DisableStreaming();
fs.close();
}
catch(OException E)
{
cout<<E.GetFailedMethodName()<< " Error: "<<E.GetErrorText()<<endl;
}
if (buffer)
free(buffer);
return 0;
}
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