Querying Mongodb Key and Value using C driver - mongodb

Question

mongo_cursor *cursor=mongo_find(conn,TEST_NS,query,NULL,0,0,0);
count_matched=0;
bson *doc;
while(mongo_cursor_next(cursor)==MONGO_OK)
{
count_matched++;
doc=(bson *)mongo_cursor_bson(cursor);
bson_iterator_init(&it,doc);
while(bson_iterator_next(&it) != BSON_EOO)
{
fprintf(stderr,"%s : %s\n\n",bson_iterator_key(&it),bson_iterator_string(&it));
}
}
This code is working perfectly and i can see the matched documents (Key + Value) but now i want to save the matched document's key and value to a string. Can any tell me how i can save the return value of key and value in to a string?
One document includes (all strings)
Total Key=10
Total value=10
and i want to save 10 document's key and value at one time. I am using C driver of mongodb.

Answer 1

The following code shows how you would be doing copy of the key and values from the bson iterator into your key-value arrays temp_key and temp_value. The specific block of code is in between the comments marked START and END.
Additionally, you can find documentation for accessing BSON document contents at http://api.mongodb.org/c/current/bson.html .
mongo_cursor *cursor = mongo_find(&conn, TEST_NS, &query, NULL, 0, 0, 0);
int count_matched = 0;
bson *doc;
// Assuming you are just looking for 100 key / value pair of max length of 99 characters
const unsigned KV_ARRAY_LENGTH = 100;
const unsigned MAX_KV_LENGTH = 105;
char temp_key[KV_ARRAY_LENGTH][MAX_KV_LENGTH + 1], temp_value[KV_ARRAY_LENGTH][MAX_KV_LENGTH + 1];
int i = 0;
while (mongo_cursor_next(cursor) == MONGO_OK) {
count_matched++;
doc=(bson *)mongo_cursor_bson(cursor);
bson_iterator it;
bson_iterator_init(&it,doc);
while (bson_iterator_next(&it) != BSON_EOO) {
fprintf(stderr,"%s : %s\n", bson_iterator_key(&it), bson_iterator_string(&it));
/******* START - Code to capture key-value into appropriate array */
if (i < KV_ARRAY_LENGTH) {
/* - Collect key-value pairs only if there is space in the array
* - Key / Value woud be captured only till the max amount of space available for them i.e. MAX_KV_LENGTH in this case
* */
strncpy(temp_key[i], bson_iterator_key(&it), MAX_KV_LENGTH);
strncpy(temp_value[i], bson_iterator_string(&it), MAX_KV_LENGTH);
temp_key[i][MAX_KV_LENGTH] = temp_value[i][MAX_KV_LENGTH] = '\0';
++i;
} else {
/* whatever need to be done if there is no room in the array */
}
/******* END - Code to capture key-value into appropriate array */
}
}
/* Test iterating through the key-value pair constructed in query iteration */
fprintf(stdout, "--- Fields collected ---\n");
int keyIndex = 0;
for ( ; keyIndex < i; ++keyIndex) {
fprintf(stdout, "{key: %s, value: %s}\n", temp_key[keyIndex], temp_value[keyIndex]);
}

Answer 2

mongo_cursor *cursor=mongo_find(conn,TEST_NS,query,NULL,0,0,0);
count_matched=0;
bson *doc;
//Answer
const char* temp_key[100][100],temp_value[100][100];
int i=0;
while(mongo_cursor_next(cursor)==MONGO_OK)
{
count_matched++;
doc=(bson *)mongo_cursor_bson(cursor);
bson_iterator_init(&it,doc);
while(bson_iterator_next(&it) != BSON_EOO)
{
fprintf(stderr,"%s : %s\n\n",bson_iterator_key(&it),bson_iterator_string(&it));
temp[i][0]=bson_iterator_key[&it]; //Answer
temp_value[i][0]=bson_iterator_key[&it]; //Answer
i++; //Answer
}
}
Just for the record, this is the rough sketch and i know about corruption of the temp variables and their overflow but i will remove it according to my code.