core19Example_main.c

Basic tutorial in C where a pure in-memory database is created, a row is inserted and then a row is retrieved and displayed. This example needs a compiled schema, core19Example.sdl.

/*
                                                    
**    IN-MEMORY
                                                    
**    ---------
                                                    
**    This document describes the process to create a simple in-memory database,
                                                    
**    insert a record, and read data from the database. This application
                                                    
*requires no
                                                    
**    persistent storage to run and can act as a simple example for disk less
                                                    
**    applications.
                                                    
*/
                                                    
 
#include "rdm.h" /* The RDM API.                   */
#include "rdmapi.h"
                                                    
#include "rdmtfsapi.h"
                                                    
#include "core19Example_structs.h" /* The core19Example database definitions.*/
#include "core19Example_cat.h"/* The core19Example database dictionary. */
                                                    
#include "rdmstartupapi.h"
                                                    
 
#include <stdio.h>
                                                    
#include <string.h>
                                                    
#include <stdlib.h>
                                                    
 
int32_t main_core19ExampleTutorial (int32_t argc, const char *const *argv)
{
RDM_RETCODE rc;
RDM_TFS tfs;
RDM_DB db = NULL;
RDM_TABLE_ID tables[] = {TABLE_INFO};
 
RDM_UNREF (argc);
RDM_UNREF (argv);
 
/* Allocate a TFS Handle */
                                                    
    rc = rdm_rdmAllocTFS (&tfs);
if (rc == sOKAY)
    {
        rc = rdm_tfsInitialize (tfs);
if (rc == sOKAY)
        {
/* Allocate a database handle */
                                                    
            rc = rdm_tfsAllocDatabase (tfs, &db);
if (rc == sOKAY)
            {
/* Associate the catalog with the database handle */
                                                    
                rc = rdm_dbSetCatalog (db, core19Example_cat);
 
if (rc == sOKAY)
                {
/* Set the in-memory volatile database option */
                                                    
                    rc = rdm_dbSetOptions (db, "storage=inmemory_volatile");
                }
 
if (rc == sOKAY)
                {
/* Open the database. */
                                                    
                    rc = rdm_dbOpen (db, "core19Example", RDM_OPEN_SHARED);
if (rc == sOKAY)
                    {
/* Start an update transaction and lock the table */
                                                    
                        rc = rdm_dbStartUpdate (
                            db, tables, RDM_LEN (tables), NULL, 0, NULL);
if (rc == sOKAY)
                        {
                            INFO infoInsert;
 
/* Create a row in the in-memory database */
                                                    
                            strcpy (
                                infoInsert.mychar, "I'm running in memory!");
                            infoInsert._mychar_has_value = RDM_COL_HAS_VALUE;
                            rc = rdm_dbInsertRow (
                                db, TABLE_INFO, &infoInsert,
sizeof (infoInsert), NULL);
 
if (rc == sOKAY)
                            {
/* Commit a transaction */
                                                    
                                rc = rdm_dbEnd (db);
                            }
else
                                                    
                            {
/* Abort the transaction */
                                                    
rdm_dbEndRollback (db);
                            }
                        }
 
                        rc = rdm_dbStartRead (
                            db, tables, RDM_LEN (tables), NULL);
if (rc == sOKAY)
                        {
RDM_CURSOR cursor = NULL;
                            rc = rdm_dbGetRows (db, TABLE_INFO, &cursor);
if (rc == sOKAY)
                            {
/* Move to the first row in the cursor */
                                                    
                                rc = rdm_cursorMoveToFirst (cursor);
if (rc == sOKAY)
                                {
                                    INFO infoRead;
 
/* read the row values */
                                                    
                                    rc = rdm_cursorReadRow (
                                        cursor, &infoRead, sizeof (infoRead),
                                        NULL);
if (rc == sOKAY)
                                    {
                                        printf ("%s\n\n", infoRead.mychar);
                                    }
else
                                                    
                                    {
                                        fprintf (
                                            stderr,
"Sorry, I can't read the first "
                                                    
"info row.");
                                    }
                                }
 
/* Free the cursor allocated in the call to
                                                    
                                 * rdm_dbGetRows */
                                                    
rdm_cursorFree (cursor);
                            }
 
rdm_dbEnd (db);
                        }
                    }
else
                                                    
                    {
                        fprintf (
                            stderr,
"Sorry, I can't open the core19Example database.");
                    }
                }
rdm_dbFree (db);
            }
        }
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 (core19ExampleTutorial)