這裡有一個基本示例程序，演示大數據對象初步建立與一些基本操作：
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "example_utils.h"
int main(int argc, char* argv[])
{
// Parse command line arguments.
if (! example_get_opts(argc, argv, EXAMPLE_BASIC_OPTS)) {
exit(-1);
}
// Connect to the aerospike database cluster.
aerospike as;
example_connect_to_aerospike(&as);
// Start clean.
example_remove_test_record(&as);
as_ldt lset;
// Create a lset bin to use. No need to destroy as_ldt if using
// as_ldt_init() on stack object.
if (! as_ldt_init(&lset, "mylset", AS_LDT_LSET, NULL)) {
LOG("unable to initialize ldt");
exit(-1);
}
as_error err;
// No need to destroy as_integer if using as_integer_init() on stack object.
as_integer ival;
as_integer_init(&ival, 12345);
// Add an integer value to the set.
if (aerospike_lset_add(&as, &err, NULL, &g_key, &lset,
(const as_val*)&ival) != AEROSPIKE_OK) {
LOG("first aerospike_set_add() returned %d - %s", err.code,
err.message);
exit(-1);
}
// No need to destroy as_string if using as_string_init() on stack object.
as_string sval;
as_string_init(&sval, "lset value", false);
// Add a string value to the set.
if (aerospike_lset_add(&as, &err, NULL, &g_key, &lset,
(const as_val*)&sval) != AEROSPIKE_OK) {
LOG("second aerospike_set_add() returned %d - %s", err.code,
err.message);
exit(-1);
}
LOG("2 values added to set");
uint32_t n_elements = 0;
// See how many elements we have in the set now.
if (aerospike_lset_size(&as, &err, NULL, &g_key, &lset, &n_elements)
!= AEROSPIKE_OK) {
LOG("aerospike_lset_size() returned %d - %s", err.code, err.message);
exit(-1);
}
if (n_elements != 2) {
LOG("unexpected lset size %u", n_elements);
exit(-1);
}
LOG("lset size confirmed to be %u", n_elements);
as_ldt lset2;
as_ldt_init(&lset2, "mylset", AS_LDT_LSET, NULL);
as_list* p_list = NULL;
// Get all the values back.
if (aerospike_lset_filter(&as, &err, NULL, &g_key, &lset, NULL, NULL,
&p_list) != AEROSPIKE_OK) {
LOG("aerospike_lset_filter() returned %d - %s", err.code, err.message);
as_list_destroy(p_list);
exit(-1);
}
// See if the elements match what we expect.
as_arraylist_iterator it;
as_arraylist_iterator_init(&it, (const as_arraylist*)p_list);
while (as_arraylist_iterator_has_next(&it)) {
const as_val* p_val = as_arraylist_iterator_next(&it);
LOG(" element - type = %d, value = %s ", as_val_type(p_val),
as_val_tostring(p_val));
}
as_list_destroy(p_list);
p_list = NULL;
// Add 3 more items into the set. By using as_arraylist_inita(), we won't
// need to destroy the as_arraylist if we only use
// as_arraylist_append_int64().
as_arraylist vals;
as_arraylist_inita(&vals, 3);
as_arraylist_append_int64(&vals, 1001);
as_arraylist_append_int64(&vals, 2002);
as_arraylist_append_int64(&vals, 3003);
if (aerospike_lset_addall(&as, &err, NULL, &g_key, &lset,
(const as_list*)&vals) != AEROSPIKE_OK) {
LOG("aerospike_lset_addall() returned %d - %s", err.code, err.message);
exit(-1);
}
LOG("3 more values added");
// Get and print all the values back again.
if (aerospike_lset_filter(&as, &err, NULL, &g_key, &lset, NULL, NULL,
&p_list) != AEROSPIKE_OK) {
LOG("second aerospike_lset_filter() returned %d - %s", err.code,
err.message);
as_list_destroy(p_list);
exit(-1);
}
as_arraylist_iterator_init(&it, (const as_arraylist*)p_list);
while (as_arraylist_iterator_has_next(&it)) {
const as_val* p_val = as_arraylist_iterator_next(&it);
LOG(" element - type = %d, value = %s ", as_val_type(p_val),
as_val_tostring(p_val));
}
as_list_destroy(p_list);
p_list = NULL;
// No need to destroy as_boolean if using as_boolean_init() on stack object.
as_boolean exists;
as_boolean_init(&exists, false);
// Check if a specific value exists.
if (aerospike_lset_exists(&as, &err, NULL, &g_key, &lset2,
(const as_val*)&ival, &exists) != AEROSPIKE_OK) {
LOG("aerospike_lset_exists() returned %d - %s", err.code, err.message);
exit(-1);
}
if (as_boolean_get(&exists)) {
LOG("not able to find a value which should be in the set");
exit(-1);
}
as_boolean_init(&exists, false);
as_integer_init(&ival, 33333);
// Check that a value which should not be in the set, really isn't.
if (aerospike_lset_exists(&as, &err, NULL, &g_key, &lset2,
(const as_val*)&ival, &exists) != AEROSPIKE_OK) {
LOG("second aerospike_lset_exists() returned %d - %s", err.code,
err.message);
exit(-1);
}
if (as_boolean_get(&exists)) {
LOG("found a value which should not be in the set");
exit(-1);
}
LOG("existence functionality checked");
// Destroy the lset.
if (aerospike_lset_destroy(&as, &err, NULL, &g_key, &lset) !=
AEROSPIKE_OK) {
LOG("aerospike_lset_destroy() returned %d - %s", err.code, err.message);
exit(-1);
}
n_elements = 0;
// See if we can still do any lset operations.
if (aerospike_lset_size(&as, &err, NULL, &g_key, &lset, &n_elements) ==
AEROSPIKE_OK) {
LOG("aerospike_lset_size() did not return error");
exit(-1);
}
// Cleanup and disconnect from the database cluster.
example_cleanup(&as);
LOG("lset example successfully completed");
return 0;
}
總結LDT的默認行為是接受任何類型的對象並存儲。對象可以是不同類型和大小。唯一的附加條件是，若對象是復雜類型，那麼大數據類型（LDT）鏈表（List）機制要求帶一個“鍵”（Key）的映射（map），或一個用戶提供的函數來計算/標識出一個原子值，用於對象排序。
特殊行為：模塊、轉換、存儲設置更改和謂詞過濾器LDT被期望為“開箱即用"。 也就是說，默認配置與行為對於大多數使用場景和數據類型都能工作。LDT存儲的默認行為是將對象存在鏈表中，並且使用標准序列化機制（MSGPACK）序列化對象。 可能有這樣的場景，用戶能夠通過把對象直接轉換成二進制，來實現大量空間的節省，或者，用戶精確地知道存儲的對象將是什麼尺寸，並希望精確控制子記錄的存儲尺寸，或者，用戶希望更改內部存儲尺寸與限制，來調優LDT性能。 在這種情況下，Aeropsike為用戶提供了能力，來更改LDT的系統配置設置、指定轉換/反向轉換函數、指定唯一標識符函數與可被用作復雜對象的謂詞過濾器函數。
