MongoDB C driver: how to use regex query collection? - c++

Question

for example, In MySQL the query like this:
select name from test_tab where id = 1 and name like 'test%';
I want to translate this query in mongodb by mongodb C driver, so I write the code like this, but all don't work(the searchDoc() function is okay.
string strName = "";
bson_t *cond = bson_new();
BSON_APPEND_INT32(cond, "id", 1);
if (strlen(name.c_str()) > 0)
{
strName = "/^" + name + "/";
bson_t *child;
child = bson_new();
bson_append_document_begin(cond, "name", -1, child);
BSON_APPEND_UTF8(child, "$regex", strName.c_str());
bson_append_document_end(cond, child);
}
mongoc_cursor_t *cursor(NULL);
int iRet = searchDoc("db", "test_tab", cond, cursor);
if (iRet < 0)
{
bson_destroy(cond);
mongoc_cursor_destroy(cursor);
return -1;
}
and
string strName = "";
bson_t *cond = bson_new();
BSON_APPEND_INT32(cond, "id", 1);
if (strlen(name.c_str()) > 0)
{
strName = "/^" + name + ".*/";
BSON_APPEND_REGEX(cond, "name", strName.c_str(), "i");
}
mongoc_cursor_t *cursor(NULL);
int iRet = searchDoc("db", "test_tab", cond, cursor);
if (iRet < 0)
{
bson_destroy(cond);
mongoc_cursor_destroy(cursor);
return -1;
}
How can I build the regex pattern to query record work okay?
Thank you

Answer 1

I seach this page: https://jira.mongodb.org/browse/CDRIVER-206,
there is a important tips: "You do not need to include the forward-slash when building a regex."
so I delete the forward-slash, my code
strName = "/^" + name + ".*/";
BSON_APPEND_REGEX(cond, "name", strName.c_str(), "i");
change to
strName = "/^" + name + ".*/";
BSON_APPEND_REGEX(cond, "name", strName.c_str(), "i");
It can work. My problem has been solved.