/*- * Public Domain 2008-2014 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 #include #include #include #include static const char *home; /*! [schema declaration] */ /* The C struct for the data we are storing in a WiredTiger table. */ typedef struct { char country[5]; uint16_t year; uint64_t population; } POP_RECORD; static POP_RECORD pop_data[] = { { "AU", 1900, 4000000 }, { "AU", 2000, 19053186 }, { "CAN", 1900, 5500000 }, { "CAN", 2000, 31099561 }, { "UK", 1900, 369000000 }, { "UK", 2000, 59522468 }, { "USA", 1900, 76212168 }, { "USA", 2000, 301279593 }, { "", 0, 0 } }; /*! [schema declaration] */ int main(void) { POP_RECORD *p; WT_CONNECTION *conn; WT_CURSOR *cursor; WT_SESSION *session; const char *country; uint64_t recno, population; uint16_t year; int ret; /* * Create a clean test directory for this run of the test program if the * environment variable isn't already set (as is done by make check). */ if (getenv("WIREDTIGER_HOME") == NULL) { home = "WT_HOME"; ret = system("rm -rf WT_HOME && mkdir WT_HOME"); } else home = NULL; if ((ret = wiredtiger_open(home, NULL, "create", &conn)) != 0) { fprintf(stderr, "Error connecting to %s: %s\n", home, wiredtiger_strerror(ret)); return (ret); } /* Note: error checking omitted for clarity. */ ret = conn->open_session(conn, NULL, NULL, &session); /*! [Create a table with column groups] */ /* * Create the population table. * Keys are record numbers, the format for values is (5-byte string, * uint16_t, uint64_t). * See ::wiredtiger_struct_pack for details of the format strings. */ ret = session->create(session, "table:poptable", "key_format=r," "value_format=5sHQ," "columns=(id,country,year,population)," "colgroups=(main,population)"); /* * Create two column groups: a primary column group with the country * code, year and population (named "main"), and a population column * group with the population by itself (named "population"). */ ret = session->create(session, "colgroup:poptable:main", "columns=(country,year,population)"); ret = session->create(session, "colgroup:poptable:population", "columns=(population)"); /*! [Create a table with column groups] */ /*! [Create an index] */ /* Create an index with a simple key. */ ret = session->create(session, "index:poptable:country", "columns=(country)"); /*! [Create an index] */ /*! [Create an index with a composite key] */ /* Create an index with a composite key (country,year). */ ret = session->create(session, "index:poptable:country_plus_year", "columns=(country,year)"); /*! [Create an index with a composite key] */ /* Insert the records into the table. */ ret = session->open_cursor( session, "table:poptable", NULL, "append", &cursor); for (p = pop_data; p->year != 0; p++) { cursor->set_value(cursor, p->country, p->year, p->population); ret = cursor->insert(cursor); } ret = cursor->close(cursor); /* List the records in the table. */ ret = session->open_cursor(session, "table:poptable", NULL, NULL, &cursor); while ((ret = cursor->next(cursor)) == 0) { ret = cursor->get_key(cursor, &recno); ret = cursor->get_value(cursor, &country, &year, &population); printf("ID %" PRIu64, recno); printf(": country %s, year %u, population %" PRIu64 "\n", country, year, population); } ret = cursor->close(cursor); /*! [List the records in the table using raw mode.] */ /* List the records in the table using raw mode. */ ret = session->open_cursor(session, "table:poptable", NULL, "raw", &cursor); while ((ret = cursor->next(cursor)) == 0) { WT_ITEM key, value; ret = cursor->get_key(cursor, &key); ret = wiredtiger_struct_unpack(session, key.data, key.size, "r", &recno); printf("ID %" PRIu64, recno); ret = cursor->get_value(cursor, &value); ret = wiredtiger_struct_unpack(session, value.data, value.size, "5sHQ", &country, &year, &population); printf(": country %s, year %u, population %" PRIu64 "\n", country, year, population); } /*! [List the records in the table using raw mode.] */ ret = cursor->close(cursor); /*! [Read population from the primary column group] */ /* * Open a cursor on the main column group, and return the information * for a particular country. */ ret = session->open_cursor( session, "colgroup:poptable:main", NULL, NULL, &cursor); cursor->set_key(cursor, 2); if ((ret = cursor->search(cursor)) == 0) { ret = cursor->get_value(cursor, &country, &year, &population); printf("ID 2: country %s, year %u, population %" PRIu64 "\n", country, year, population); } /*! [Read population from the primary column group] */ ret = cursor->close(cursor); /*! [Read population from the standalone column group] */ /* * Open a cursor on the population column group, and return the * population of a particular country. */ ret = session->open_cursor(session, "colgroup:poptable:population", NULL, NULL, &cursor); cursor->set_key(cursor, 2); if ((ret = cursor->search(cursor)) == 0) { ret = cursor->get_value(cursor, &population); printf("ID 2: population %" PRIu64 "\n", population); } /*! [Read population from the standalone column group] */ ret = cursor->close(cursor); /*! [Search in a simple index] */ /* Search in a simple index. */ ret = session->open_cursor(session, "index:poptable:country", NULL, NULL, &cursor); cursor->set_key(cursor, "AU\0\0\0"); ret = cursor->search(cursor); ret = cursor->get_value(cursor, &country, &year, &population); printf("AU: country %s, year %u, population %" PRIu64 "\n", country, (unsigned int)year, population); /*! [Search in a simple index] */ ret = cursor->close(cursor); /*! [Search in a composite index] */ /* Search in a composite index. */ ret = session->open_cursor(session, "index:poptable:country_plus_year", NULL, NULL, &cursor); cursor->set_key(cursor, "USA\0\0", (uint16_t)1900); ret = cursor->search(cursor); ret = cursor->get_value(cursor, &country, &year, &population); printf("US 1900: country %s, year %u, population %" PRIu64 "\n", country, (unsigned int)year, population); /*! [Search in a composite index] */ ret = cursor->close(cursor); /*! [Return a subset of values from the table] */ /* * Use a projection to return just the table's country and year * columns. */ ret = session->open_cursor(session, "table:poptable(country,year)", NULL, NULL, &cursor); while ((ret = cursor->next(cursor)) == 0) { ret = cursor->get_value(cursor, &country, &year); printf("country %s, year %u\n", country, year); } /*! [Return a subset of values from the table] */ ret = cursor->close(cursor); /*! [Return a subset of values from the table using raw mode] */ /* * Use a projection to return just the table's country and year * columns, using raw mode. */ ret = session->open_cursor(session, "table:poptable(country,year)", NULL, "raw", &cursor); while ((ret = cursor->next(cursor)) == 0) { WT_ITEM value; ret = cursor->get_value(cursor, &value); ret = wiredtiger_struct_unpack( session, value.data, value.size, "5sH", &country, &year); printf("country %s, year %u\n", country, year); } /*! [Return a subset of values from the table using raw mode] */ ret = cursor->close(cursor); /*! [Return the table's record number key using an index] */ /* * Use a projection to return just the table's record number key * from an index. */ ret = session->open_cursor(session, "index:poptable:country_plus_year(id)", NULL, NULL, &cursor); while ((ret = cursor->next(cursor)) == 0) { ret = cursor->get_key(cursor, &country, &year); ret = cursor->get_value(cursor, &recno); printf("row ID %" PRIu64 ": country %s, year %u\n", recno, country, year); } /*! [Return the table's record number key using an index] */ ret = cursor->close(cursor); /*! [Return a subset of the value columns from an index] */ /* * Use a projection to return just the population column from an * index. */ ret = session->open_cursor(session, "index:poptable:country_plus_year(population)", NULL, NULL, &cursor); while ((ret = cursor->next(cursor)) == 0) { ret = cursor->get_key(cursor, &country, &year); ret = cursor->get_value(cursor, &population); printf("population %" PRIu64 ": country %s, year %u\n", population, country, year); } /*! [Return a subset of the value columns from an index] */ ret = cursor->close(cursor); /*! [Access only the index] */ /* * Use a projection to avoid accessing any other column groups when * using an index: supply an empty list of value columns. */ ret = session->open_cursor(session, "index:poptable:country_plus_year()", NULL, NULL, &cursor); while ((ret = cursor->next(cursor)) == 0) { ret = cursor->get_key(cursor, &country, &year); printf("country %s, year %u\n", country, year); } /*! [Access only the index] */ ret = cursor->close(cursor); ret = conn->close(conn, NULL); return (ret); }