How to read a file in an Oracle BLOB field

Use ORADBI to read multiple files stored in a BLOB field and restore to a specified path.

Here's the complete code:

//


//READ_BLOBFILE.C-Read the blobfile example


//cheungmine@gmail.com//


//Memory leak detection


//Place the statement where needed to be detected:


//_CrtDumpMemoryLeaks ();


//The Order of the following 3 sentences cannot be changed


#define _CRTDBG_MAP_ALLOC


#include <stdlib.h>


#include <crtdbg.h>





//contains a unique ORADBI header file


#include ". /oradbi.h "





#ifdef _DEBUG


#pragma comment (lib, ". /oradbi_dll/debug/oradbid.lib ")


#else


#pragma comment (lib, ". /oradbi_dll/release/oradbi.lib ")


#endif








#define Oradb_service "CHEUNG"


#define Oradb_loguser "MINEUSR"


#define Oradb_password "Minepwd"





/*==================================================


--Create table


CREATE TABLE TEST


(


BM VARCHAR2 (10),


NAME VARCHAR2 (100),


Birth DATE,


DATA BLOB


)


tablespace USERS


Pctfree 10


Initrans 1


Maxtrans 255


Storage


　 (


Initial 64K


minextents 1


Maxextents Unlimited


　 );


====================================================*/





//


//shows how to read data from a BLOB field and revert to a file


//


void Select_blob_data ()


{


Lresult RC;


ora_error_t err;


ora_connection con = 0;


ora_sqlstmt stmt = 0;


Ora_rowset rs = 0;


Ora_column Col;


Ora_datetime odt;


Char *psz;


Char buf[30];


char **pp_fnames = 0;


ushort num_files = 0;


UShort UI;








//Create connection


rc = Ora_connection_create (&con, Oradb_service, Oradb_loguser, Oradb_password, oci_threaded| Oci_object, FALSE, &err);


assert (rc==orc_success);





//Create SQL, take only one line of records: where Rownum<2


rc = ora_sqlstmt_create (&stmt, con, "select Bm,name,birth,data from TEST where rownum<2",-1, 0, &er R);


assert (rc==orc_success);





//Executive selection


rc = Ora_sqlstmt_select (stmt, Mod_default, &rs, &err);


assert (rc==orc_success);





printf ("N BM NAME birth Datan---------------------------------------------------- --n ");





while (Ora_rowset_next (RS))


　　　 {


//BM


col = Ora_rowset_get_column_by_index (RS, 1, &err);


assert (Ora_column_not_null (col));


ora_column_as_string (col, &psz, &err);


printf ("%s", psz);





//NAME


col = Ora_rowset_get_column_by_index (RS, 2, &err);


assert (Ora_column_not_null (col));


ora_column_as_string (col, &psz, &err);


printf ("%s", psz);





//Birth


col = Ora_rowset_get_column_by_index (RS, 3, &err);


assert (Ora_column_not_null (col));


Ora_column_as_datetime (col, &odt, &err);


ora_datetime_to_string (ODT, "Yyyy-mm-dd HH:UU:SS", buf, &err);


printf ("%s", buf);





//DATA


col = Ora_rowset_get_column_by_index (RS, 4, &err);


assert (Ora_column_not_null (col));





//Read LOB field data, write to file:


rc = ora_column_read_lobfile (col, "C:\Temp", &pp_fnames, &num_files, &err);


assert (rc==orc_success);





for (ui=0 ui<num_files; ui++) {


printf ("n%s", Pp_fnames[ui]);


　　　　　　　 }


Ora_string_list_free (Pp_fnames, num_files);





printf ("n");


　　　 }





//Release


Ora_rowset_free (RS);


Ora_sqlstmt_free (stmt);


ora_connection_free (con);


}





//


//Main program


//


int main (int argc, char* argv[])


{


Select_blob_data ();





_CrtDumpMemoryLeaks ();





return 0;


}

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