Function: simpleFlatten

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    Goal: Flatten a document for integration with a non-NOSQL RDBMS.

    • This function simpleFlatten shows how a document can be flattened into a RDBMS importable record.

    • Requires Eventing Storage (or metadata collection), a "source" collection, and a "destination" collection.

    • Will operate on all documents where doc.type === "tosync".

    • Will write transformed or flattened documents to the destination bucket with the same type and id.

    • Will also remove the flattened document in the destination bucket when the original source document is removed.

    • The "destination" collection can be shared (or replicated via XCDR to a business partner) too the cloud (AWS, Azure or GCP).

    • Note since the document is not available during an OnDelete we will filter by KEY prefix starting with "tosync:".*. This is a hard coded implementation. Refer to genericFlatten for a generic implementation.

    • simpleFlatten

    • Input Data/Mutation

    • Output Data/Mutation

    // To run configure the settings for this Function, simpleFlatten, as follows:
    //
    // Version 7.0+
    //   "Listen to Location"
    //     bulk.data.source
    //   "Eventing Storage"
    //     rr100.eventing.metadata
    //   Binding(s)
    //    1. "binding type", "alias name...", "bucket.scope.collection", "Access"
    //       "bucket alias", "dst_col",       "bulk.data.destination",   "read and write"
    //
    // Version 6.X
    //   "Source Bucket"
    //     source
    //   "MetaData Bucket"
    //     metadata
    //   Binding(s)
    //    1. "binding type", "alias name...", "bucket",     "Access"
    //       "bucket alias", "dst_col",      "destination", "read and write"
    
    function OnUpdate(doc, meta) {
        // filter
        if (!doc.type || doc.type !== "tosync") return;
    
        log("OnUpdate IN  id: "+meta.id+", doc:      ",doc);
        try {
            // convert
            var oracleDoc = {
                // flatten items simple 1:1 map
                "id": doc.id, "type":doc.type,
                // flatten subdoc
                "a_sub_aa": doc.a.aa, "a_sub_ab": doc.a.ab,  "a_sub_ac": doc.a.ac,
                // flatten array
                "b_ary_0": doc.b[0], "b_ary_1": doc.b[1], "b_ary_2": doc.b[2]
            }
            // log
            log("OnUpdate OUT id: "+meta.id+", oracleDoc:",oracleDoc);
        } catch (e) {
            log ("Error on convert: "+e+", id:",meta.id);
        }
        // save
        try {
            dst_col[meta.id] = oracleDoc;
        } catch (e) {
            log("Error on save: "+e+", id:", meta.id);
        }
    }
    
    function OnDelete(meta, options) {
        // filter
        if (!(meta.id.startsWith("tosync:"))) return;
    
        log("OnDelete expired=" + options.expired +" REM id: "+meta.id);
        try {
            delete dst_col[meta.id];
        } catch (e) {
            log("Error on delete: "+e+", id:",meta.id);
        }
    }
    INPUT: KEY tosync::1
    
    {
      "id": 1,
      "type": "tosync",
      "a": {
        "aa": 1,
        "ab": 2,
        "ac": 3
      },
      "b": [
        1,
        3,
        7
      ]
    }
    UPDATED/OUTPUT: KEY tosync::1
    
    {
      "id": 1,
      "type": "tosync",
      "a_sub_aa": 1,
      "a_sub_ab": 2,
      "a_sub_ac": 3,
      "b_ary_0": 1,
      "b_ary_1": 3,
      "b_ary_2": 7
    }