如何通过_id在MongoDB中查找记录?
为了在MongoDB中通过_id查找记录,可以使用以下语法
db.yourCollectionName.find({"_id":yourObjectId});
让我们创建包含文档的集合
> db.findRecordByIdDemo.insertOne({"CustomerName":"Larry","CustomerAge":26}); { "acknowledged" : true, "insertedId" : ObjectId("5c9dc2c875e2eeda1d5c3671") } > db.findRecordByIdDemo.insertOne({"CustomerName":"Bob","CustomerAge":20}); { "acknowledged" : true, "insertedId" : ObjectId("5c9dc2d175e2eeda1d5c3672") } > db.findRecordByIdDemo.insertOne({"CustomerName":"Carol","CustomerAge":22}); { "acknowledged" : true, "insertedId" : ObjectId("5c9dc2d775e2eeda1d5c3673") } > db.findRecordByIdDemo.insertOne({"CustomerName":"David","CustomerAge":24}); { "acknowledged" : true, "insertedId" : ObjectId("5c9dc2e375e2eeda1d5c3674") }
以下是查询以借助find()方法显示集合中的所有文档
> db.findRecordByIdDemo.find().pretty();
这将产生以下输出
{ "_id" : ObjectId("5c9dc2c875e2eeda1d5c3671"), "CustomerName" : "Larry", "CustomerAge" : 26 } { "_id" : ObjectId("5c9dc2d175e2eeda1d5c3672"), "CustomerName" : "Bob", "CustomerAge" : 20 } { "_id" : ObjectId("5c9dc2d775e2eeda1d5c3673"), "CustomerName" : "Carol", "CustomerAge" : 22 } { "_id" : ObjectId("5c9dc2e375e2eeda1d5c3674"), "CustomerName" : "David", "CustomerAge" : 24 } Following is the query to find record by _id in MongoDB: > db.findRecordByIdDemo.find({"_id":ObjectId("5c9dc2d175e2eeda1d5c3672")}).pretty();
这将产生以下输出
{ "_id" : ObjectId("5c9dc2d175e2eeda1d5c3672"), "CustomerName" : "Bob", "CustomerAge" : 20 }