Indexes

Indexes

Sometimes, it's desirable to have indexes on your dataset - especially unique ones. In order to do that, you must fill the indexes attribute. The indexes attribute is a list of dictionary with the following structure:

• "fields":

  take a list of fields or a field name (required)

• "unique": should this index guarantee uniqueness? (optional, False by default)
• "ttl": (optional, 300 by default) time window (in seconds) during which this index will be recognized by subsequent calls to ensure_index - see pymongo documentation for ensure_index for details.
• "check": (optional, True by default) don't check if the field name is present in the structure. Useful if you don't know the field name.

Example:

>>> class MyDoc(Document):
...     structure = {
...         'standard':unicode,
...         'other':{
...             'deep':unicode,
...         },
...         'notindexed':unicode,
...     }
...     
...     indexes = [
...         {
...             'fields':['standard', 'other.deep'],
...             'unique':True,
...         },
...     ]

or if you have more than one index:

>>> class Movie(Document):
...     db_name = 'test'
...     collection_name = 'mongokit'
...     structure = {
...         'standard':unicode,
...         'other':{
...             'deep':unicode,
...         },
...         'alsoindexed':unicode,
...     }
... 
...     indexes = [
...         {
...             'fields':'standard',
...             'unique':True,
...         },
...         {
...             'fields': ['alsoindexed', 'other.deep']
...         },
...     ]

By default, the index direction is set to 1. You can change the direction by passing a list of tuple. Direction must be one of INDEX_ASCENDING (or 1), INDEX_DESCENDING (or -1), INDEX_OFF (or 0), INDEX_ALL (or 2) or INDEX_GEO2D (or '2d'):

>>> class MyDoc(Document):
...     structure = {
...         'standard':unicode,
...         'other':{
...             'deep':unicode,
...         },
...         'notindexed':unicode,
...     }
...     
...     indexes = [
...         {
...             'fields':[('standard',INDEX_ASCENDING), ('other.deep',INDEX_DESCENDING)],
...             'unique':True,
...         },
...     ]

To prevent adding an index on the wrong field (misspelled for instance), MongoKit will check by default the indexes descriptor. In some cases may want to disable this. To do so, add "check":True:

>>> class MyDoc(Document):
...    structure = {
...        'foo': dict,
...        'bar': int
...    }
...    indexes = [
...        # I know this field is not in the document structure, don't check it
...        {'fields':['foo.title'], 'check':False}
...    ]

In this example, we index the field foo.title which is not explicitly specified in the structure.