core37Example_main.c

CLOB example in C language. This example needs a compiled schema, core37Example.sdl.

/*

 * HELLO WORLD

 * -----------

 *

 * This document describes the process to create a simple database,

 * insert a record containing a text field, read the text field from

 * database and print it out.

 */

 
#include "rdm.h"/* The RDM API. */

#include "core37Example_structs.h" /* The core01Example database definitions. */
#include "core37Example_cat.h"/* The core01Example database catalog */

#include "rdmstartupapi.h"

 
#include <stdio.h>

#include <string.h>

#include <stdlib.h>

 
#define DBNAME "core37"

#define SAMPLETEXT "The quick brown fox jumps over the lazy dog. "

 
/* Remove the database to cleanup the example */

static void cleanup(RDM_TFS tfs)
{
rdm_tfsDropDatabase(tfs, DBNAME);
}
 
 
static RDM_RETCODE updateClob(RDM_CURSOR cursor, RDM_COLUMN_ID col)
{
RDM_RETCODE rc = sOKAY;
char buffer[] = { SAMPLETEXT };
 uint64_t offset;
size_t bufSize;
 
/* Setting bufSize to the length of the actual data 

 * rather than the length of the buffer. For this 

 * example we are excluding the NULL byte at the end 

 * of the input string so the strings will be appended 

 * together.

 */

 bufSize = strlen(buffer);
 
/* Appending characters into CLOB until approximately 2000 characters reached */

for (offset = 0; offset < 2000 && rc == sOKAY; offset += bufSize)
 {
 rc = rdm_cursorUpdateBlob(cursor, col, offset, buffer, bufSize);
 }
return rc;
}
 
static RDM_RETCODE readClob(RDM_CURSOR cursor, RDM_COLUMN_ID col)
{
RDM_RETCODE rc = sOKAY;
char buffer[1000];
 uint64_t offset;
size_t bytesOut;
size_t charactersOut;
 uint64_t numCharacters;
 
/* Read entire contents of CLOB using 1000 byte buffer */

 rc = rdm_cursorGetClobSize(cursor, col, &numCharacters);
if (rc == sOKAY && numCharacters > 0)
 {
/* Only read blob if there are characters stored. A

 * zero numCharacters indicates the CLOB is empty.

 */

for (offset = 0; rc == sOKAY; offset += charactersOut )
 {
/* in the following, the bytesIn value is reduced by 1 character 

 * to allow a NULL byte to be appended to the buffer later

 */

 rc = rdm_cursorReadClob(cursor, col, offset, buffer, sizeof(buffer)-1, &bytesOut, &charactersOut);
if (bytesOut == 0)
break; /* bytesOut == 0 indicates end of CLOB has been reached */
 
/* Since we put the string into the CLOB w/o a NULL terminator,

 * we need to add it to the end of buffer we are printing.

 */

 buffer[bytesOut] = '\0';
 printf("%s", buffer);
 }
 }
return rc;
}
 
 
 
static RDM_RETCODE readARow (RDM_DB db, uint32_t id)
{
RDM_TABLE_ID tables[] = {TABLE_INFO};
RDM_RETCODE rc;
 
/* Start an update transaction and lock the table */

 rc = rdm_dbStartRead (db, tables, RDM_LEN (tables), NULL);
if (rc == sOKAY)
 {
 INFO_ID_KEY idLookup;
RDM_CURSOR cursor = NULL;
 
/* Find the requested row */

 idLookup.id = id;
 rc = rdm_dbGetRowsByKeyAtKey(db, KEY_INFO_ID, &idLookup, sizeof(idLookup), &cursor);
if (rc == sOKAY)
 {
 INFO infoRead; /* Row buffer */
 
/* Read the full content of the current record */

 rc = rdm_cursorReadRow (cursor, &infoRead, sizeof (infoRead), NULL);
if (rc == sOKAY)
 {
 printf ("ID\t: %08u\n", infoRead.id);
 printf ("Model\t: %s\n", infoRead.model);
 printf ("Comment\t: \n");
if (infoRead._description_has_value == RDM_TRUE)
 {
 rc = readClob(cursor, COL_INFO_DESCRIPTION);
 }
else

 {
 puts("**NULL DESCRIPTION**");
 }
 printf("\n");
 }
 }
if (cursor)
 {
/* Free the cursor */

rdm_cursorFree (cursor);
 }
/* Free the read lock on the table */

rdm_dbEnd (db);
 }
return rc;
}
 
 
static RDM_RETCODE writeARow (RDM_DB db, uint32_t id)
{
RDM_TABLE_ID tables[] = {TABLE_INFO};
RDM_CURSOR cursor = NULL;
RDM_RETCODE rc;
 
/* Start an update transaction and lock the table */

 rc = rdm_dbStartUpdate (db, tables, RDM_LEN (tables), NULL, 0, NULL);
if (rc == sOKAY)
 {
 INFO infoInserted; /* Row buffer */
 
/* Populate the mychar column in the Row buffer */

 infoInserted.id = id;
 sprintf(infoInserted.model, "Model #%x", id);
 infoInserted._description_has_value = RDM_FALSE;
 
/* Insert a row into the table */

 rc = rdm_dbInsertRow (
 db, TABLE_INFO, &infoInserted, sizeof (infoInserted), &cursor);
if (rc == sOKAY)
 {
 uint32_t task = (id % 2);
 
/* The example will add a Description CLOB to every other ID */

if (task == 0)
 {
 rc = updateClob(cursor, COL_INFO_DESCRIPTION);
 }
 }
if (rc == sOKAY)
 {
/* Commit a transaction */

 rc = rdm_dbEnd (db);
 }
else

 {
/* Abort the transaction */

rdm_dbEndRollback (db);
 }
 }
return rc;
}
 
int32_t main_core37 (int32_t argc, const char *const *argv)
{
RDM_RETCODE rc; /* Status/Error Return Code */
RDM_TFS tfs; /* TFS Handle */
 
RDM_UNREF (argc);
RDM_UNREF (argv);
 
/* Allocate a TFS Handle */

 rc = rdm_rdmAllocTFS (&tfs);
if (rc == sOKAY)
 {
 rc = rdm_tfsInitialize (tfs);
if (rc == sOKAY)
 {
RDM_DB db;
 
/* Allocate a database hande */

 rc = rdm_tfsAllocDatabase (tfs, &db);
if (rc == sOKAY)
 {
/* Associate the catalog with the database handle */

 rc = rdm_dbSetCatalog(db, core37Example_cat);
if (rc == sOKAY)
 {
/* Open the database */

 rc = rdm_dbOpen(db, DBNAME, RDM_OPEN_SHARED);
if (rc != sOKAY)
 {
 printf("I can't open the " DBNAME " database.\n");
 }
else

 {
/* insert 10 rows into the database */

for (uint32_t ii = 0; ii < 10 && rc == sOKAY; ii++)
 {
 rc = writeARow(db, 1000+ii);
 }
/* Read ids #4 and #5 */

 readARow(db, 1004);
 readARow(db, 1005);
 
rdm_dbClose(db);
 }
 }
rdm_dbFree (db);
 }
 cleanup (tfs);
 }
rdm_tfsFree (tfs);
 }
 
if (rc != sOKAY)
 {
 printf (
"There was an error in this Tutorial (%s - %s)\n",
rdm_retcodeGetName (rc), rdm_retcodeGetDescription (rc));
return EXIT_FAILURE;
 }
 
return EXIT_SUCCESS;
}
 
RDM_STARTUP_EXAMPLE (core37)