diff --git a/packages/strapi-bookshelf/lib/index.js b/packages/strapi-bookshelf/lib/index.js
index df935aec88..ebfa6321bf 100755
--- a/packages/strapi-bookshelf/lib/index.js
+++ b/packages/strapi-bookshelf/lib/index.js
@@ -236,6 +236,7 @@ module.exports = function(strapi) {
                         const association = definition.associations
                           .filter(association => association.nature.toLowerCase().indexOf('morph') !== -1)
                           .filter(association => association.alias === path || association.via === path)[0];
+
                         if (association) {
                           // Override on polymorphic path only.
                           if (_.isString(path) && path === association.via) {
@@ -252,7 +253,11 @@ module.exports = function(strapi) {
                               strapi.plugins[association.plugin].models[association.collection || association.model]:
                               strapi.models[association.collection || association.model];
 
-                            return `${association.alias}.${model.collectionName}`;
+                            return {
+                              [`${association.alias}.${model.collectionName}`]: function(query) {
+                                query.orderBy('created_at', 'desc');
+                              }
+                            };
                           }
                         }
 
diff --git a/packages/strapi-plugin-content-manager/config/queries/bookshelf.js b/packages/strapi-plugin-content-manager/config/queries/bookshelf.js
index 706cb3b649..f09885db4e 100755
--- a/packages/strapi-plugin-content-manager/config/queries/bookshelf.js
+++ b/packages/strapi-plugin-content-manager/config/queries/bookshelf.js
@@ -218,6 +218,28 @@ module.exports = {
                 strapi.plugins[obj.source].models[obj.ref]:
                 strapi.models[obj.ref];
 
+              // Remove existing relationship because only one file
+              // can be related to this field.
+              if (association.nature === 'manyMorphToOne') {
+                return virtualFields.push(
+                  module.exports.removeRelationMorph.call(this, {
+                    alias: association.alias,
+                    ref: model.collectionName,
+                    refId: obj.refId,
+                    field: obj.field
+                  })
+                  .then(() =>
+                    module.exports.addRelationMorph.call(this, {
+                      id: response[this.primaryKey],
+                      alias: association.alias,
+                      ref: model.collectionName,
+                      refId: obj.refId,
+                      field: obj.field
+                    })
+                  )
+                );
+              }
+
               virtualFields.push(module.exports.addRelationMorph.call(this, {
                 id: response[this.primaryKey],
                 alias: association.alias,
@@ -386,12 +408,12 @@ module.exports = {
 
   removeRelationMorph: async function (params) {
     return await this.morph.forge()
-      .where({
+      .where(_.omitBy({
         [`${this.collectionName}_id`]: params.id,
         [`${params.alias}_id`]: params.refId,
         [`${params.alias}_type`]: params.ref,
         field: params.field
-      })
+      }, _.isEmpty))
       .destroy();
   }
 };