Function: simpleFlatten

    March 16, 2025
    + 12

    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.

    javascript
    // To run configure the settings for this Function, simpleFlatten, as follows: // // Version 7.1+ // "Function Scope" // *.* (or try bulk.data if non-privileged) // 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); } }