Shows how to create column-oriented data and access individual columns.
/*- * Copyright (c) 2008-2012 WiredTiger, Inc. * * This is free and unencumbered software released into the public domain. * * Anyone is free to copy, modify, publish, use, compile, sell, or * distribute this software, either in source code form or as a compiled * binary, for any purpose, commercial or non-commercial, and by any * means. * * In jurisdictions that recognize copyright laws, the author or authors * of this software dedicate any and all copyright interest in the * software to the public domain. We make this dedication for the benefit * of the public at large and to the detriment of our heirs and * successors. We intend this dedication to be an overt act of * relinquishment in perpetuity of all present and future rights to this * software under copyright law. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. * * ex_schema.c * This is an example application demonstrating how to create and access * tables using a schema. */ #include <stdio.h> #include <string.h> #include <inttypes.h> #include <wiredtiger.h> const char *home = "WT_TEST"; /* The C struct for the data we are storing with WiredTiger. */ typedef struct { char country[5]; uint16_t year; uint64_t population; } POP_RECORD; POP_RECORD pop_data[] = { { "USA", 1980, 226542250 }, { "USA", 2009, 307006550 }, { "UK", 2008, 61414062 }, { "CAN", 2008, 33311400 }, { "AU", 2008, 21431800 } }; int main(void) { int ret; WT_CONNECTION *conn; WT_SESSION *session; WT_CURSOR *cursor; POP_RECORD *p, *endp; const char *country; uint64_t recno; uint16_t year; ret = wiredtiger_open(home, NULL, "create", &conn); if (ret != 0) fprintf(stderr, "Error connecting to %s: %s\n", home, wiredtiger_strerror(ret)); /* Note: error checking omitted for clarity. */ ret = conn->open_session(conn, NULL, NULL, &session); /* * Create the population table. * Keys are record numbers, the format for values is * (5-byte string, short, long). * See ::wiredtiger_struct_pack for details of the format strings. * * If this program is run multiple times so the table already exists, * this call will verify that the table exists. It is not required in * that case, but is a safety check that the schema matches what the * program expects. */ ret = session->create(session, "table:population", "key_format=r," "value_format=5sHQ," "columns=(id,country,year,population)," "colgroups=(main,population)"); /* Create the column groups to store population in its own file. */ ret = session->create(session, "colgroup:population:main", "columns=(country,year)"); ret = session->create(session, "colgroup:population:population", "columns=(population)"); /* Create an index with composite key (country,year). */ ret = session->create(session, "index:population:country_year", "columns=(country,year)"); ret = session->open_cursor(session, "table:population", NULL, "append", &cursor); endp = pop_data + (sizeof (pop_data) / sizeof (pop_data[0])); for (p = pop_data; p < endp; p++) { cursor->set_value(cursor, p->country, p->year, p->population); ret = cursor->insert(cursor); } ret = cursor->close(cursor); /* Now just read through the countries we know about */ ret = session->open_cursor(session, "index:population:country_year(id)", NULL, NULL, &cursor); while ((ret = cursor->next(cursor)) == 0) { cursor->get_key(cursor, &country, &year); cursor->get_value(cursor, &recno); printf("Got country %s : row ID %d\n", country, (int)recno); } ret = conn->close(conn, NULL); return (ret); }