Question

我正在用C编写MongoDB的GUI客户端。我使用C driver for MongoDB。我想获得一个数据库及其集合的列表，但我找不到documentation中的任何函数来执行此操作。

如何使用C驱动程序获取数据库和集合列表？

Answer 1

这里的其他答案似乎有一半完整，甚至与C / C ++接口无关。经过深思熟虑后，这对我有用：

string serverHost("127.0.0.1:27017");
mongo::DBClientConnection conn;
string errmsg;
if( conn.connect( serverHost, errmsg ) )
{
  BSONObj cmd = mongo::fromjson( "{listDatabases: 1}" );
  BSONObj info;
  if( conn.runCommand( "admin", cmd, info ) )
  {
    BSONElement arrayel = info.getField("databases");
    std::vector<BSONElement> mdArray = arrayel.Array();
    std::vector<BSONElement>::iterator iter;
    for( iter=mdArray.begin(); iter!=mdArray.end(); ++iter )
    {
      BSONElement element = *iter;
      BSONObj obj = element.Obj();

      // HERE IS THE DATABASE NAME
      string dbname = obj.getStringField("name");

      // HERE IS THE LIST OF COLLECTIONS, BUT MAY NEED TO IGNORE ONE
      // TITLED "system.indexes"
      list<string> collNamespaces =
          conn.getCollectionNames(dbname);

      list<string>::iterator iter2 = collNamespaces.begin();
      while( iter2 != collNamespaces.end() )
      {
        // EACH ENTRY HAS THE FULL NAMESPACE ("database:collection").
        // Use this method to strip off the database name
        string collectionName = mongo::nsGetCollection(*iter2);

        ++iter2;
      } // END WHILE iterate through collections
    } // END WHILE iterate through databases
  } // END IF runCommand() returned success
} // END IF database connected

Answer 2

我认为您必须使用mongo_run_command(mongo *conn, const char * db, bson *command, bson *out) command是BSON命令。您应该能够使用定义的命令here。请注意，某些命令要求在数据库admin上发出它们。所以在mongodb shell中，可以像这样查询数据库列表：

> use admin
switched to db admin
> db.runCommand({listDatabases: 1})
{
    "databases" : [
        {
            "name" : "geo",
            "sizeOnDisk" : 14975762432,
            "empty" : false
        },
        {
            "name" : "local",
            "sizeOnDisk" : 1,
            "empty" : true
        }
    ],
    "totalSize" : 14975762432,
    "ok" : 1
}

通过此操作的结果，您可以查询每个数据库以查找可用的集合。我没有尝试使用C接口，但我相信你应该能够通过调用mongo_run_command并传递适当的参数来实现同样的目的。

Answer 3

要获取数据库中的所有馆藏名称，您可以使用<?php // get database connection include_once 'config/database.php'; $database = new Database(); $db = $database->getConnection(); class Facturas{ // database connection and table name private $conn; private $table_name = "factura"; // object properties public $id; public $cliente; public function __construct($db){ $this->conn = $db; } function create(){ $query = "INSERT INTO " . $this->table_name . " SET cliente = :cliente"; $stmt = $this->conn->prepare($query); $stmt->bindParam(':cliente', $this->cliente); if($stmt->execute()){ return true; }else{ return false; } } } $factura = new facturas($db); class DetalleFacturas{ // database connection and table name private $conn; private $table_name = "detallefactura"; // object properties public $id; public $fac_id; public $tratamiento; public function __construct($db){ $this->conn = $db; } function create(){ $query = "INSERT INTO " . $this->table_name . " SET fac_id = :fac_id, tratamiento = :tratamiento"; $stmt = $this->conn->prepare($query); $stmt->bindParam(':fac_id', $fac_ids); $stmt->bindParam(':tratamiento', $tratamientos); if (is_array($this->tratamiento)) { foreach ($this->tratamiento as $clave=> $tratamientos) { $fac_ids = $this->fac_id[$clave]; $stmt->execute(); } } } } $detallefactura = new detallefacturas($db); if ($_POST){ $factura->cliente = $_POST['cliente']; $factura->create(); $last[] = $db->lastInsertId('factura'); $detallefactura->fac_id = $last; $detallefactura->tratamiento = $_POST['tratamiento']; $detallefactura->create(); } else { echo "no va"; } ?> <form action='prueba2.php' method='post'> <table class='table table-hover table-responsive table-bordered'> <tr> <td>Cliente</td> <td><input type='text' name='cliente' class='form-control'></td> </tr> <tr> <td>Tratamiento</td> <td><input type='text' name='tratamiento[]' class='form-control'></td> </tr> <tr> <td>Tratamiento2</td> <td><input type='text' name='tratamiento[]' class='form-control'></td> </tr> <tr> <td> <button type='submit' class='btn btn-primary'>Crear</button> </td> </tr> </table> </form> <pre><?php print_r($detallefactura) ?></pre>

mongoc_database_get_collection_names

Answer 4

Matlab驱动程序提供了两个功能： mongo_get_databases （）和： mongo_get_database_collections（）（下面的示例代码段），它们似乎提供了您的功能要求：

EXPORT mxArray* mongo_get_databases(struct mongo_* conn) {
    bson out;
    mxArray* ret;
    int count = 0;
    bson_iterator it, databases, database;
    int i = 0;

    if (mongo_simple_int_command((mongo*)conn, "admin", "listDatabases", 1, &out) != MONGO_OK) {
        bson_destroy(&out);
        return 0;
    }
    bson_iterator_init(&it, &out);

    ...

    bson_destroy(&out);
    return ret;
}

如何获取MongoDB服务器上的数据库和集合列表？

4 个答案: