Return an explanation of the query, often useful for optimization and debugging

# MongoCursor::explain

(PECL mongo >=0.9.2)

MongoCursor::explain — Return an explanation of the query, often useful for optimization and debugging

### Descrierea

public MongoCursor::explain ( void ) : array

### Parametri

Această funcție nu are parametri.

### Valorile întoarse

Returns an explanation of the query.

### Exemple

Example #1 MongoCursor::explain() example

`<?php
$cursor = $collection->find(array("x"=>1), array("y"));
$cursor->sort(array("z" => 1))->limit(4)->skip(5);
var_dump($cursor->explain());
?>`

Exemplul de mai sus va afișa ceva similar cu:

    array(8) {
      ["cursor"]=>
      string(15) "BtreeCursor x_1"
      ["startKey"]=>
      array(1) {
        ["x"]=>
        int(1)
      }
      ["endKey"]=>
      array(1) {
        ["x"]=>
        int(1)
      }
      ["nscanned"]=>
      float(4)
      ["n"]=>
      int(4)
      ["scanAndOrder"]=>
      int(1)
      ["millis"]=>
      int(3)
      ["allPlans"]=>
      array(2) {
        [0]=>
        array(3) {
          ["cursor"]=>
          string(15) "BtreeCursor x_1"
          ["startKey"]=>
          array(1) {
            ["x"]=>
            int(1)
          }
          ["endKey"]=>
          array(1) {
            ["x"]=>
            int(1)
          }
        }
        [1]=>
        array(3) {
          ["cursor"]=>
          string(11) "BasicCursor"
          ["startKey"]=>
          array(0) {
          }
          ["endKey"]=>
          array(0) {
          }
        }
      }
    }

### Erori/Excepții

Throws MongoConnectionException if it cannot reach the database.

### A se vedea și

MongoDB core docs on » explain.