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diff --git a/src/app/db/service/pivot/helpers.js b/src/app/db/service/pivot/helpers.js
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+/**
+ * Pivot Table Helpers
+ * @module app/db/service/pivot/helpers
+ */
+
+import * as db from "app/db/query";
+
+/**
+ * Fetch a set of database objects from a pivot table via relations
+ * @param {bookshelf.Model} Model              the pivot table model to query
+ * @param {string}          parentIdAttribute  the parent ID attribute on the pivot
+ * @param {number}          parentId           the parent ID to query
+ * @param {string}          childIdAttribute   the child ID attribute on the pivot
+ * @param {number}          childId            the child ID to query
+ */
+export function indexPivotTable({
+  Model,
+  parentIdAttribute,
+  parentId,
+  childIdAttribute,
+  childId,
+}) {
+  return Model.query((builder) => {
+    builder.where(parentIdAttribute, parentId);
+    if (Array.isArray(childId)) {
+      builder.whereIn(childIdAttribute, childId);
+    } else {
+      builder.andWhere(childIdAttribute, childId);
+    }
+  }).fetchAll();
+}
+
+/**
+ * Get the parent, child, and pivot models from a service, as well as their ID attribute names
+ * @param  {Service} service  the pivot table service
+ * @return {object}           the models and ID attribute names
+ */
+export function getPivotModels(service) {
+  const {
+    parent,
+    Model,
+    ChildModel,
+    childRelation,
+    parentPivotRelation,
+    pivotChildRelation,
+  } = service.options;
+  const { Model: ParentModel } = service.options.parent;
+  const parentIdAttribute = ParentModel.prototype.idAttribute;
+  const pivotIdAttribute = Model.prototype.idAttribute;
+  const childIdAttribute = ChildModel.prototype.idAttribute;
+  const parentTableName = ParentModel.prototype.tableName;
+  const pivotTableName = Model.prototype.tableName;
+  const childTableName = ChildModel.prototype.tableName;
+  return {
+    parent,
+    Model,
+    ParentModel,
+    ChildModel,
+    parentTableName,
+    pivotTableName,
+    childTableName,
+    parentIdAttribute,
+    pivotIdAttribute,
+    childIdAttribute,
+    parentPivotRelation,
+    pivotChildRelation,
+    childRelation,
+  };
+}
+
+/**
+ * Create a single instance
+ * @param  {bookshelf.Model} options.Model     the model
+ * @param  {Object}          options.data      data to add
+ * @param  {Array}           options.instances fetched instances to dedupe
+ * @return {Object}                            result
+ */
+export async function handleCreateOne({ Model, data, instances }) {
+  if (instances.length) {
+    throw new Error("pivot relation already exists");
+  }
+  return await db.create({ Model, data });
+}
+
+/**
+ * Create multiple instances
+ * @param  {bookshelf.Model} options.Model             the model
+ * @param  {Object}          options.data              data to add
+ * @param  {Array}           options.instances         fetched instances to dedupe
+ * @param  {string}          options.childIdAttribute  the child ID, found on the body, which should point to an array
+ * @return {Object}                                    result
+ */
+export async function handleCreateMany({
+  Model,
+  data,
+  childIdAttribute,
+  instances,
+}) {
+  let { [childIdAttribute]: child_ids, ...columns } = data;
+  const matched = new Set(
+    instances.map((instance) => instance.get(childIdAttribute))
+  );
+  return await Promise.all(
+    Array.from(new Set(child_ids))
+      .filter((child_id) => !matched.has(child_id))
+      .map((child_id) =>
+        db.create({
+          Model,
+          data: { ...columns, [childIdAttribute]: child_id },
+        })
+      )
+  );
+}