NoSQL- automatically cache and update references to other documents as embedded












1















To avoid having to look up referenced documents, one practice is to embed them (e.g. https://docs.mongodb.com/manual/tutorial/model-embedded-one-to-many-relationships-between-documents/).



Is there a way to have those embedded documents actually be separate and be referenced yet be "automatically embedded" like by some sort of functionality which automatically stores their data in the document which is referencing them - almost like an automatic "embedding cache" of sorts.



I'm not referring to them being automatically retrieved by reference, but an actual copy being stored and updated automatically.



I know this could be built manually, but I'm wondering what may exist already which can do this, preferably something inherent to MongoDB, but it doesn't have to be.



While I'm asking this about MongoDB in particular, if someone knows of something like this for other NoSQL databases, I'd be interested to hear about that as well as an answer.










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    1















    To avoid having to look up referenced documents, one practice is to embed them (e.g. https://docs.mongodb.com/manual/tutorial/model-embedded-one-to-many-relationships-between-documents/).



    Is there a way to have those embedded documents actually be separate and be referenced yet be "automatically embedded" like by some sort of functionality which automatically stores their data in the document which is referencing them - almost like an automatic "embedding cache" of sorts.



    I'm not referring to them being automatically retrieved by reference, but an actual copy being stored and updated automatically.



    I know this could be built manually, but I'm wondering what may exist already which can do this, preferably something inherent to MongoDB, but it doesn't have to be.



    While I'm asking this about MongoDB in particular, if someone knows of something like this for other NoSQL databases, I'd be interested to hear about that as well as an answer.










    share|improve this question














    bumped to the homepage by Community 22 mins ago


    This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.


















      1












      1








      1








      To avoid having to look up referenced documents, one practice is to embed them (e.g. https://docs.mongodb.com/manual/tutorial/model-embedded-one-to-many-relationships-between-documents/).



      Is there a way to have those embedded documents actually be separate and be referenced yet be "automatically embedded" like by some sort of functionality which automatically stores their data in the document which is referencing them - almost like an automatic "embedding cache" of sorts.



      I'm not referring to them being automatically retrieved by reference, but an actual copy being stored and updated automatically.



      I know this could be built manually, but I'm wondering what may exist already which can do this, preferably something inherent to MongoDB, but it doesn't have to be.



      While I'm asking this about MongoDB in particular, if someone knows of something like this for other NoSQL databases, I'd be interested to hear about that as well as an answer.










      share|improve this question














      To avoid having to look up referenced documents, one practice is to embed them (e.g. https://docs.mongodb.com/manual/tutorial/model-embedded-one-to-many-relationships-between-documents/).



      Is there a way to have those embedded documents actually be separate and be referenced yet be "automatically embedded" like by some sort of functionality which automatically stores their data in the document which is referencing them - almost like an automatic "embedding cache" of sorts.



      I'm not referring to them being automatically retrieved by reference, but an actual copy being stored and updated automatically.



      I know this could be built manually, but I'm wondering what may exist already which can do this, preferably something inherent to MongoDB, but it doesn't have to be.



      While I'm asking this about MongoDB in particular, if someone knows of something like this for other NoSQL databases, I'd be interested to hear about that as well as an answer.







      mongodb nosql






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      asked Mar 9 '17 at 17:13









      g491g491

      1061




      1061





      bumped to the homepage by Community 22 mins ago


      This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.







      bumped to the homepage by Community 22 mins ago


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          1 Answer
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          You may be looking for MongoDB Aggregation pipeline stage $lookup.



          Example:
          A collection orders contains the following documents:



          { "_id" : 1, "item" : "abc", "price" : 12, "quantity" : 2 }
          { "_id" : 2, "item" : "jkl", "price" : 20, "quantity" : 1 }


          Another collection inventory contains the following documents:



          { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
          { "_id" : 4, "sku" : "jkl", description: "product 4", "instock" : 70 }


          The following aggregation operation on the orders collection joins the documents from orders with the documents from the inventory collection



          db.orders.aggregate([
          {
          $lookup:
          {
          from: "inventory",
          localField: "item",
          foreignField: "sku",
          as: "inventory_docs"
          }
          }
          ])


          Example output:



          {
          "_id" : 1,
          "item" : "abc",
          "price" : 12,
          "quantity" : 2,
          "inventory_docs" : [
          { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
          ]
          }


          See more examples.



          You could combine $lookup with $out stage to create another collection. See related $graphLookup






          share|improve this answer























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            0














            You may be looking for MongoDB Aggregation pipeline stage $lookup.



            Example:
            A collection orders contains the following documents:



            { "_id" : 1, "item" : "abc", "price" : 12, "quantity" : 2 }
            { "_id" : 2, "item" : "jkl", "price" : 20, "quantity" : 1 }


            Another collection inventory contains the following documents:



            { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
            { "_id" : 4, "sku" : "jkl", description: "product 4", "instock" : 70 }


            The following aggregation operation on the orders collection joins the documents from orders with the documents from the inventory collection



            db.orders.aggregate([
            {
            $lookup:
            {
            from: "inventory",
            localField: "item",
            foreignField: "sku",
            as: "inventory_docs"
            }
            }
            ])


            Example output:



            {
            "_id" : 1,
            "item" : "abc",
            "price" : 12,
            "quantity" : 2,
            "inventory_docs" : [
            { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
            ]
            }


            See more examples.



            You could combine $lookup with $out stage to create another collection. See related $graphLookup






            share|improve this answer




























              0














              You may be looking for MongoDB Aggregation pipeline stage $lookup.



              Example:
              A collection orders contains the following documents:



              { "_id" : 1, "item" : "abc", "price" : 12, "quantity" : 2 }
              { "_id" : 2, "item" : "jkl", "price" : 20, "quantity" : 1 }


              Another collection inventory contains the following documents:



              { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
              { "_id" : 4, "sku" : "jkl", description: "product 4", "instock" : 70 }


              The following aggregation operation on the orders collection joins the documents from orders with the documents from the inventory collection



              db.orders.aggregate([
              {
              $lookup:
              {
              from: "inventory",
              localField: "item",
              foreignField: "sku",
              as: "inventory_docs"
              }
              }
              ])


              Example output:



              {
              "_id" : 1,
              "item" : "abc",
              "price" : 12,
              "quantity" : 2,
              "inventory_docs" : [
              { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
              ]
              }


              See more examples.



              You could combine $lookup with $out stage to create another collection. See related $graphLookup






              share|improve this answer


























                0












                0








                0







                You may be looking for MongoDB Aggregation pipeline stage $lookup.



                Example:
                A collection orders contains the following documents:



                { "_id" : 1, "item" : "abc", "price" : 12, "quantity" : 2 }
                { "_id" : 2, "item" : "jkl", "price" : 20, "quantity" : 1 }


                Another collection inventory contains the following documents:



                { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
                { "_id" : 4, "sku" : "jkl", description: "product 4", "instock" : 70 }


                The following aggregation operation on the orders collection joins the documents from orders with the documents from the inventory collection



                db.orders.aggregate([
                {
                $lookup:
                {
                from: "inventory",
                localField: "item",
                foreignField: "sku",
                as: "inventory_docs"
                }
                }
                ])


                Example output:



                {
                "_id" : 1,
                "item" : "abc",
                "price" : 12,
                "quantity" : 2,
                "inventory_docs" : [
                { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
                ]
                }


                See more examples.



                You could combine $lookup with $out stage to create another collection. See related $graphLookup






                share|improve this answer













                You may be looking for MongoDB Aggregation pipeline stage $lookup.



                Example:
                A collection orders contains the following documents:



                { "_id" : 1, "item" : "abc", "price" : 12, "quantity" : 2 }
                { "_id" : 2, "item" : "jkl", "price" : 20, "quantity" : 1 }


                Another collection inventory contains the following documents:



                { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
                { "_id" : 4, "sku" : "jkl", description: "product 4", "instock" : 70 }


                The following aggregation operation on the orders collection joins the documents from orders with the documents from the inventory collection



                db.orders.aggregate([
                {
                $lookup:
                {
                from: "inventory",
                localField: "item",
                foreignField: "sku",
                as: "inventory_docs"
                }
                }
                ])


                Example output:



                {
                "_id" : 1,
                "item" : "abc",
                "price" : 12,
                "quantity" : 2,
                "inventory_docs" : [
                { "_id" : 1, "sku" : "abc", description: "product 1", "instock" : 120 }
                ]
                }


                See more examples.



                You could combine $lookup with $out stage to create another collection. See related $graphLookup







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Mar 29 '17 at 4:19









                Wan BachtiarWan Bachtiar

                1013




                1013






























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