ensureSparseIndex() public method

Sparse indexes only contain entries for documents that have the indexed field, even if the index field contains a null value. The index skips over any document that is missing the indexed field.
See link: http://docs.mongodb.org/manual/core/index-sparse/
public ensureSparseIndex ( array $key ) : Collection
$key array An array specifying the index's fields as its keys. For each field, the value is either the index direction or index type. If specifying direction, specify 1 for ascending or -1 for descending.
return Collection
Collection Class Documentation
Example #1
0
 public function testEnsureSparseIndex()
 {
     $this->collection->ensureSparseIndex(array('sparseAsc' => 1, 'sparseDesc' => -1));
     $indexes = $this->collection->getIndexes();
     $this->assertEquals(array('sparseAsc' => 1, 'sparseDesc' => -1), $indexes[1]['key']);
     $this->assertArrayHasKey('sparse', $indexes[1]);
 }