The SQLite Database Engine

Listing 2: C API example.

#include <stdlib.h>
#include <stdio.h>
#include <sqlite.h>
typedef struct sqlite_vm sqlite_vm;
int main()
{
   const char* db_name = "db";
   sqlite *db; /* The database handle */
   char *sql = "select projectname_full as name, rating, license "
               "from project order by rating desc limit 10";
   const char *tail; /* Points to next SQL statement to process, if any. */
   char *err_msg; /* Last error message, if any. */

   sqlite_vm *pvm; /* Virtual machine for executing query. */
   db = sqlite_open(db_name, 0, &err_msg);
   if(db==0)
   {
      fprintf(stderr, "Can't open database: %s\n", err_msg);
      exit(1);
   }
   /* Compile SQL, allocate a virtual machine for processing. */
   int ret = sqlite_compile(db,sql,&tail,&pvm,&err_msg);
   if(ret != SQLITE_OK)
   {
      fprintf(stderr, "Compile failed: %s\n", err_msg);
      sqlite_freemem(err_msg);
      exit(1);
   }
   int i, ncols;
   const char** fields;
   const char** col_defs;
   ret = sqlite_step(pvm, &ncols, &fields, &col_defs);
   /* Print Column Names */
   printf("%35s %5s %40s\n\n", col_defs[0], col_defs[1], col_defs[2]);
   /* Print Column Datatypes */
   printf("%35s %5s %40s\n\n", col_defs[3], col_defs[4], col_defs[5]);
   /* Print Result Set */
   while(ret == SQLITE_ROW)
   {
      printf("%35s %5s %40s\n", fields[0], fields[1], fields[2]);
      ret = sqlite_step(pvm, &ncols, &fields, &col_defs);
   }
   ret = sqlite_finalize(pvm, &err_msg);
   if(ret != SQLITE_OK)
   {
      fprintf(stderr, "Finalize failed: %s\n", err_msg);
      sqlite_freemem(err_msg);
      exit(1);
   }
   sqlite_close(db);
}