11from django .db .backends .base .schema import BaseDatabaseSchemaEditor
2+ from django .db .models import Index
3+ from pymongo import ASCENDING , DESCENDING
4+ from pymongo .operations import IndexModel
25
36from .query import wrap_database_errors
47
@@ -13,11 +16,30 @@ def get_database(self):
1316 @wrap_database_errors
1417 def create_model (self , model ):
1518 self .get_database ().create_collection (model ._meta .db_table )
19+ self ._create_model_indexes (model )
1620 # Make implicit M2M tables.
1721 for field in model ._meta .local_many_to_many :
1822 if field .remote_field .through ._meta .auto_created :
1923 self .create_model (field .remote_field .through )
2024
25+ def _create_model_indexes (self , model ):
26+ """
27+ Create all indexes (field indexes, index_together, Meta.indexes) for
28+ the specified model.
29+ """
30+ if not model ._meta .managed or model ._meta .proxy or model ._meta .swapped :
31+ return
32+ # Field indexes
33+ for field in model ._meta .local_fields :
34+ if self ._field_should_be_indexed (model , field ):
35+ self ._add_field_index (model , field )
36+ # Meta.index_together (RemovedInDjango51Warning)
37+ for field_names in model ._meta .index_together :
38+ self ._add_composed_index (model , field_names )
39+ # Meta.indexes
40+ for index in model ._meta .indexes :
41+ self .add_index (model , index )
42+
2143 def delete_model (self , model ):
2244 # Delete implicit M2m tables.
2345 for field in model ._meta .local_many_to_many :
@@ -35,6 +57,9 @@ def add_field(self, model, field):
3557 self .get_collection (model ._meta .db_table ).update_many (
3658 {}, [{"$set" : {column : self .effective_default (field )}}]
3759 )
60+ # Add an index, if required.
61+ if self ._field_should_be_indexed (model , field ):
62+ self ._add_field_index (model , field )
3863
3964 def _alter_field (
4065 self ,
@@ -66,21 +91,68 @@ def remove_field(self, model, field):
6691 # Unset field on existing documents.
6792 if column := field .column :
6893 self .get_collection (model ._meta .db_table ).update_many ({}, {"$unset" : {column : "" }})
94+ if self ._field_should_be_indexed (model , field ):
95+ self ._remove_field_index (model , field )
6996
7097 def alter_index_together (self , model , old_index_together , new_index_together ):
7198 pass
7299
73100 def alter_unique_together (self , model , old_unique_together , new_unique_together ):
74101 pass
75102
76- def add_index (self , model , index ):
77- pass
78-
79- def rename_index (self , model , old_index , new_index ):
80- pass
103+ def add_index (self , model , index , field = None ):
104+ if index .contains_expressions :
105+ return
106+ index_orders = (
107+ [(field .column , ASCENDING )]
108+ if field
109+ else [
110+ # order is "" if ASCENDING or "DESC" if DESCENDING (see
111+ # django.db.models.indexes.Index.fields_orders).
112+ (model ._meta .get_field (field_name ).column , ASCENDING if order == "" else DESCENDING )
113+ for field_name , order in index .fields_orders
114+ ]
115+ )
116+ idx = IndexModel (index_orders , name = index .name )
117+ self .get_collection (model ._meta .db_table ).create_indexes ([idx ])
118+
119+ def _add_composed_index (self , model , field_names ):
120+ """Add an index on the given list of field_names."""
121+ idx = Index (fields = field_names )
122+ idx .set_name_with_model (model )
123+ self .add_index (model , idx )
124+
125+ def _add_field_index (self , model , field ):
126+ """Add an index on a field with db_index=True."""
127+ index = Index (fields = [field .name ])
128+ index .name = self ._create_index_name (model ._meta .db_table , [field .column ])
129+ self .add_index (model , index , field = field )
81130
82131 def remove_index (self , model , index ):
83- pass
132+ if index .contains_expressions :
133+ return
134+ self .get_collection (model ._meta .db_table ).drop_index (index .name )
135+
136+ def _remove_field_index (self , model , field ):
137+ """Remove a field's db_index=True index."""
138+ collection = self .get_collection (model ._meta .db_table )
139+ meta_index_names = {index .name for index in model ._meta .indexes }
140+ index_names = self ._constraint_names (
141+ model ,
142+ [field .column ],
143+ index = True ,
144+ # Retrieve only BTREE indexes since this is what's created with
145+ # db_index=True.
146+ type_ = Index .suffix ,
147+ exclude = meta_index_names ,
148+ )
149+ if len (index_names ) != 1 :
150+ num_found = len (index_names )
151+ raise ValueError (
152+ f"Found wrong number ({ num_found }
153+ f"{ model ._meta .db_table } { field .column }
154+ )
155+ collection .drop_index (index_names [0 ])
84156
85157 def add_constraint (self , model , constraint ):
86158 pass
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