MongoDB插入密鑰'$'（美元）

Question

我想插入一個包含以'$'（例如：'$count'）開頭的密鑰的json對象的集合。我讀了MongoDB的V3.0 FAQ's，他們已經提到它不是這樣的關鍵。有沒有什麼迂迴的方式插入這樣一把鑰匙並將其取回？

Answer 1

Field names cannot contain dots (i.e. .) or null characters, and they must not start with a dollar sign (i.e. $).

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In some cases, you may wish to build a BSON object with a user-provided key. In these situations, keys will need to substitute the reserved $ and . characters. Any character is sufficient, but consider using the Unicode full width equivalents: U+FF04 (i.e. 「＄」) and U+FF0E (i.e. 「．」).

是不是recomanded，但你可以試試這個：

dollar = "\uFF04"; 
＄ 
dot = "\uFF0E" 
． 

db.test.save({[dollar]:dot}) 
WriteResult({ "nInserted" : 1 }) 
db.test.save({[dot]:dollar}) 
WriteResult({ "nInserted" : 1 }) 

db.test.find() 
{ "_id" : ObjectId("58256b0f9934a5d1c696c456"), "＄" : "．" } 
{ "_id" : ObjectId("58256d359934a5d1c696c457"), "．" : "＄" }