Pour ce faire de manière atomique, vos trois exemples de documents doivent faire partie du même document. MongoDB n'effectue des opérations de manière atomique que sur des documents simples :http://www.mongodb.org/ display/DOCS/Atomic+Operations
S'ils font partie d'un seul document, ce qui suit modifierait l'ordre des 2e et 3e sous-documents :
> db.so.find().pretty();{ "_id" :ObjectId("4f55e7ba362e2f2a734c92f8"), "subs" :[ { "author_id" :"a", "class" :"principe", "content_id" :null, "host_id" :null, "modified_date" :1330935540, "order" :1, "pub_date" :1330935540, "score" :0, "text" :"Hello World！", "vote_down_count" :0, "vote_up_count" :0 }, { "author_id" :"a", "class" :"principle", "content_id" :null, "host_id" :null, "modified_date" :1330935538, "order" :2, "pub_date" :1330935538, "score" :0, "text" :"Ravi de vous rencontrer.", "vote_down_count" :0, "vote_up_count" :0 }, { "author_id" :"a", "class" :"principe", "content_id" : null, "host_id" : null, "modified_date" :1330935548, "order" :3, "pub_date" :1330935548, "score" :0, "text" :"Génial !", "vote_down_count" :0, "vote_up_count" :0 } ]} Requête :
db.so.update( { _id:new ObjectId("4f55e7ba362e2f2a734c92f8")}, { $set :{ 'subs.1.order' :3, 'subs.2.order' :2 } });
Résultat :
> db.so.find().pretty();{ "_id" :ObjectId("4f55e7ba362e2f2a734c92f8"), "subs" :[ { "author_id" :"a", "class" :"principe", "content_id" :null, "host_id" :null, "modified_date" :1330935540, "order" :1, "pub_date" :1330935540, "score" :0, "text" :"Hello World！", "vote_down_count" :0, "vote_up_count" :0 }, { "author_id" :"a", "class" :"principle", "content_id" :null, "host_id" :null, "modified_date" :1330935538, "order" :3, "pub_date" :1330935538, "score" :0, "text" :"Ravi de vous rencontrer.", "vote_down_count" :0, "vote_up_count" :0 }, { "author_id" :"a", "class" :"principe", "content_id" : null, "host_id" : null, "modified_date" :1330935548, "order" :2, "pub_date" :1330935548, "score" :0, "text" :"Génial !", "vote_down_count" :0, "vote_up_count" :0 } ]}
