1MONGOC_COLLECTION_COUNT_DOCUMENTMSo(n3g)oDB C DrMiOvNeGrOC_COLLECTION_COUNT_DOCUMENTS(3)
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NAME

6       mongoc_collection_count_documents - mongoc_collection_count_documents()
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SYNOPSIS

9          int64_t
10          mongoc_collection_count_documents (mongoc_collection_t *collection,
11                                             const bson_t *filter,
12                                             const bson_t *opts,
13                                             const mongoc_read_prefs_t *read_prefs,
14                                             bson_t *reply,
15                                             bson_error_t *error);
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PARAMETERS

18       · collection: A mongoc_collection_t.
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20       · filter: A bson_t containing the filter.
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22       · opts: A bson_t, NULL to ignore.
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24       · read_prefs: A mongoc_read_prefs_t or NULL.
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26       · reply:  A  location  for an uninitialized bson_t to store the command
27         reply, NULL to ignore. If not NULL, reply will be initialized.
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29       · error: An optional location for a bson_error_t or NULL.
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31       opts may be NULL or a BSON document with additional command options:
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33       · readConcern:  Construct  a   mongoc_read_concern_t   and   use   mon‐
34         goc_read_concern_append  to  add  the  read  concern to opts. See the
35         example code for mongoc_client_read_command_with_opts.  Read  concern
36         requires MongoDB 3.2 or later, otherwise an error is returned.
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38       · sessionId:  First,  construct  a  mongoc_client_session_t  with  mon‐
39         goc_client_start_session. You  can  begin  a  transaction  with  mon‐
40         goc_client_session_start_transaction, optionally with a mongoc_trans‐
41         action_opt_t that overrides the options  inherited  from  collection,
42         and  use mongoc_client_session_append to add the session to opts. See
43         the example code for mongoc_client_session_t.
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45       · collation:  Configure  textual  comparisons.  See  Setting  Collation
46         Order,  and the MongoDB Manual entry on Collation. Collation requires
47         MongoDB 3.2 or later, otherwise an error is returned.
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49       · serverId: To target a specific server, include  an  int32  "serverId"
50         field.  Obtain  the  id  by calling mongoc_client_select_server, then
51         mongoc_server_description_id on its return value.
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53       · skip: An int specifying how many documents matching the query  should
54         be skipped before counting.
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56       · limit: An int specifying the maximum number of documents to count.
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DESCRIPTION

59       This  functions  executes a count query on collection. In contrast with
60       mongoc_collection_estimated_document_count(),  the  count  returned  is
61       guaranteed to be accurate.
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ERRORS

64       Errors are propagated via the error parameter.
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RETURNS

67       -1 on failure, otherwise the number of documents counted.
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EXAMPLE

70          #include <bson/bson.h>
71          #include <mongoc/mongoc.h>
72          #include <stdio.h>
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74          static void
75          print_count (mongoc_collection_t *collection, bson_t *filter)
76          {
77             bson_error_t error;
78             int64_t count;
79             bson_t* opts = BCON_NEW ("skip", BCON_INT64(5));
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81             count = mongoc_collection_count_documents (
82                collection, filter, opts, NULL, NULL, &error);
83             bson_destroy (opts);
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85             if (count < 0) {
86                fprintf (stderr, "Count failed: %s\n", error.message);
87             } else {
88                printf ("%" PRId64 " documents counted.\n", count);
89             }
90          }
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MIGRATING FROM DEPRECATED COUNT FUNCTIONS

93       When migrating to mongoc_collection_count_documents from the deprecated
94       mongoc_collection_count or mongoc_collection_count_with_opts, the  fol‐
95       lowing query operators in the filter must be replaced:
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97                     ┌────────────┬────────────────────────────┐
98                     │Operator    │ Replacement                │
99                     ├────────────┼────────────────────────────┤
100                     │$where      │ $expr                      │
101                     ├────────────┼────────────────────────────┤
102                     │$near       │ $geoWithin with $center    │
103                     ├────────────┼────────────────────────────┤
104                     │$nearSphere │ $geoWithin            with │
105                     │            │ $centerSphere              │
106                     └────────────┴────────────────────────────┘
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108       $expr requires MongoDB 3.6+
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SEE ALSO

111       mongoc_collection_estimated_document_count()
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AUTHOR

114       MongoDB, Inc
115

117       2017-present, MongoDB, Inc
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1221.14.0                           Feb 22, 20M1O9NGOC_COLLECTION_COUNT_DOCUMENTS(3)
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