diff --git a/src/app.js b/src/app.js
index 578517eb1..4becd4c67 100644
--- a/src/app.js
+++ b/src/app.js
@@ -56,7 +56,7 @@ app.use((req, res, next) => {
 
 // error handler
 app.use((err, req, res, next) => {
-    log.error(err.message);
+    log.info(err);
 
     res.status(err.status || 500);
     res.send({
diff --git a/src/entities/attribute.js b/src/entities/attribute.js
index 2cecc29dd..0504a5696 100644
--- a/src/entities/attribute.js
+++ b/src/entities/attribute.js
@@ -4,7 +4,7 @@ const Entity = require('./entity');
 
 class Attribute extends Entity {
     async getNote() {
-        return this.sql.getEntity("SELECT * FROM notes WHERE noteId = ?", [this.noteId]);
+        return this.repository.getEntity("SELECT * FROM notes WHERE noteId = ?", [this.noteId]);
     }
 }
 
diff --git a/src/entities/entity.js b/src/entities/entity.js
index 0228fab42..71e6dc1ea 100644
--- a/src/entities/entity.js
+++ b/src/entities/entity.js
@@ -1,8 +1,12 @@
 "use strict";
 
+const utils = require('../services/utils');
+
 class Entity {
-    constructor(sql, row) {
-        this.sql = sql;
+    constructor(repository, row) {
+        utils.assertArguments(repository, row)
+
+        this.repository = repository;
 
         for (const key in row) {
             this[key] = row[key];
diff --git a/src/entities/note.js b/src/entities/note.js
index 35a0b0e3b..6409630e1 100644
--- a/src/entities/note.js
+++ b/src/entities/note.js
@@ -3,28 +3,32 @@
 const Entity = require('./entity');
 
 class Note extends Entity {
-    constructor(sql, row) {
-        super(sql, row);
+    constructor(repository, row) {
+        super(repository, row);
 
-        if (this.type === "code" && this.mime === "application/json") {
+        if (this.isJson()) {
             this.jsonContent = JSON.parse(this.content);
         }
     }
 
+    isJson() {
+        return this.type === "code" && this.mime === "application/json";
+    }
+
     async getAttributes() {
-        return this.sql.getEntities("SELECT * FROM attributes WHERE noteId = ?", [this.noteId]);
+        return this.repository.getEntities("SELECT * FROM attributes WHERE noteId = ?", [this.noteId]);
     }
 
     async getAttribute(name) {
-        return this.sql.getEntity("SELECT * FROM attributes WHERE noteId = ? AND name = ?", [this.noteId, name]);
+        return this.repository.getEntity("SELECT * FROM attributes WHERE noteId = ? AND name = ?", [this.noteId, name]);
     }
 
     async getRevisions() {
-        return this.sql.getEntities("SELECT * FROM note_revisions WHERE noteId = ?", [this.noteId]);
+        return this.repository.getEntities("SELECT * FROM note_revisions WHERE noteId = ?", [this.noteId]);
     }
 
     async getTrees() {
-        return this.sql.getEntities("SELECT * FROM note_tree WHERE isDeleted = 0 AND noteId = ?", [this.noteId]);
+        return this.repository.getEntities("SELECT * FROM note_tree WHERE isDeleted = 0 AND noteId = ?", [this.noteId]);
     }
 }
 
diff --git a/src/entities/note_revision.js b/src/entities/note_revision.js
index 17419b6e1..0e8c71f32 100644
--- a/src/entities/note_revision.js
+++ b/src/entities/note_revision.js
@@ -4,7 +4,7 @@ const Entity = require('./entity');
 
 class NoteRevision extends Entity {
     async getNote() {
-        return this.sql.getEntity("SELECT * FROM notes WHERE noteId = ?", [this.noteId]);
+        return this.repository.getEntity("SELECT * FROM notes WHERE noteId = ?", [this.noteId]);
     }
 }
 
diff --git a/src/entities/note_tree.js b/src/entities/note_tree.js
index 391c4780b..94dee1834 100644
--- a/src/entities/note_tree.js
+++ b/src/entities/note_tree.js
@@ -4,11 +4,11 @@ const Entity = require('./entity');
 
 class NoteTree extends Entity {
     async getNote() {
-        return this.sql.getEntity("SELECT * FROM note_tree WHERE isDeleted = 0 AND noteId = ?", [this.noteId]);
+        return this.repository.getEntity("SELECT * FROM note_tree WHERE isDeleted = 0 AND noteId = ?", [this.noteId]);
     }
 
     async getParentNote() {
-        return this.sql.getEntity("SELECT * FROM note_tree WHERE isDeleted = 0 AND parentNoteId = ?", [this.parentNoteId]);
+        return this.repository.getEntity("SELECT * FROM note_tree WHERE isDeleted = 0 AND parentNoteId = ?", [this.parentNoteId]);
     }
 }
 
diff --git a/src/routes/api/script.js b/src/routes/api/script.js
index 2782ccd4a..81d2b185c 100644
--- a/src/routes/api/script.js
+++ b/src/routes/api/script.js
@@ -4,11 +4,10 @@ const express = require('express');
 const router = express.Router();
 const auth = require('../../services/auth');
 const wrap = require('express-promise-wrap').wrap;
-const sql = require('../../services/sql');
 const notes = require('../../services/notes');
-const protected_session = require('../../services/protected_session');
 const attributes = require('../../services/attributes');
 const script = require('../../services/script');
+const Repository = require('../../services/repository');
 
 router.post('/exec/:noteId', auth.checkApiAuth, wrap(async (req, res, next) => {
     const noteId = req.params.noteId;
@@ -33,9 +32,11 @@ router.get('/startup', auth.checkApiAuth, wrap(async (req, res, next) => {
 router.get('/subtree/:noteId', auth.checkApiAuth, wrap(async (req, res, next) => {
     const noteId = req.params.noteId;
 
-    const noteScript = (await notes.getNoteById(noteId, req)).content;
+    const repository = new Repository(req);
 
-    const subTreeScripts = await getSubTreeScripts(noteId, [noteId], req);
+    const noteScript = (await repository.getNote(noteId)).content;
+
+    const subTreeScripts = await getSubTreeScripts(noteId, [noteId], repository);
 
     res.send(subTreeScripts + noteScript);
 }));
@@ -48,15 +49,14 @@ async function getNoteWithSubtreeScript(noteId, req) {
     return subTreeScripts + noteScript;
 }
 
-async function getSubTreeScripts(parentId, includedNoteIds, dataKey) {
-    const children = await sql.getRows(`SELECT notes.noteId, notes.title, notes.content, notes.isProtected, notes.mime 
-                                     FROM notes JOIN note_tree USING(noteId)
-                                     WHERE note_tree.isDeleted = 0 AND notes.isDeleted = 0
+async function getSubTreeScripts(parentId, includedNoteIds, repository) {
+    const children = await repository.getEntities(`
+                                      SELECT notes.* 
+                                      FROM notes JOIN note_tree USING(noteId)
+                                      WHERE note_tree.isDeleted = 0 AND notes.isDeleted = 0
                                            AND note_tree.parentNoteId = ? AND notes.type = 'code'
                                            AND (notes.mime = 'application/javascript' OR notes.mime = 'text/html')`, [parentId]);
 
-    protected_session.decryptNotes(dataKey, children);
-
     let script = "\r\n";
 
     for (const child of children) {
@@ -66,7 +66,7 @@ async function getSubTreeScripts(parentId, includedNoteIds, dataKey) {
 
         includedNoteIds.push(child.noteId);
 
-        script += await getSubTreeScripts(child.noteId, includedNoteIds, dataKey);
+        script += await getSubTreeScripts(child.noteId, includedNoteIds, repository);
 
         if (child.mime === 'application/javascript') {
             child.content = '<script>' + child.content + '</script>';
diff --git a/src/services/attributes.js b/src/services/attributes.js
index 08419ef61..e365ecd04 100644
--- a/src/services/attributes.js
+++ b/src/services/attributes.js
@@ -3,7 +3,7 @@
 const sql = require('./sql');
 const utils = require('./utils');
 const sync_table = require('./sync_table');
-const protected_session = require('./protected_session');
+const Repository = require('./repository');
 
 async function getNoteAttributeMap(noteId) {
     return await sql.getMap(`SELECT name, value FROM attributes WHERE noteId = ?`, [noteId]);
@@ -15,21 +15,19 @@ async function getNoteIdWithAttribute(name, value) {
 }
 
 async function getNotesWithAttribute(dataKey, name, value) {
+    const repository = new Repository(dataKey);
+
     let notes;
 
     if (value !== undefined) {
-        notes = await sql.getEntities(`SELECT notes.* FROM notes JOIN attributes USING(noteId) 
+        notes = await repository.getEntities(`SELECT notes.* FROM notes JOIN attributes USING(noteId) 
           WHERE notes.isDeleted = 0 AND attributes.name = ? AND attributes.value = ?`, [name, value]);
     }
     else {
-        notes = await sql.getEntities(`SELECT notes.* FROM notes JOIN attributes USING(noteId) 
+        notes = await repository.getEntities(`SELECT notes.* FROM notes JOIN attributes USING(noteId) 
           WHERE notes.isDeleted = 0 AND attributes.name = ?`, [name]);
     }
 
-    for (const note of notes) {
-        protected_session.decryptNote(dataKey, note);
-    }
-
     return notes;
 }
 
diff --git a/src/services/notes.js b/src/services/notes.js
index 010c533d0..38b1cf797 100644
--- a/src/services/notes.js
+++ b/src/services/notes.js
@@ -5,21 +5,6 @@ const sync_table = require('./sync_table');
 const attributes = require('./attributes');
 const protected_session = require('./protected_session');
 
-async function getNoteById(noteId, dataKey) {
-    const note = await sql.getEntity("SELECT * FROM notes WHERE noteId = ?", [noteId]);
-
-    protected_session.decryptNote(dataKey, note);
-
-    return note;
-}
-
-async function getJsonNoteById(noteId, dataKey) {
-    const note = await getNoteById(noteId, dataKey);
-    note.data = JSON.parse(note.content);
-
-    return note;
-}
-
 async function updateJsonNote(noteId, data) {
     const ret = await createNewNote(noteId, {
         title: name,
@@ -329,7 +314,6 @@ async function deleteNote(noteTreeId, sourceId) {
 }
 
 module.exports = {
-    getNoteById,
     createNewNote,
     updateNote,
     deleteNote,
diff --git a/src/services/repository.js b/src/services/repository.js
new file mode 100644
index 000000000..b13a8c54b
--- /dev/null
+++ b/src/services/repository.js
@@ -0,0 +1,62 @@
+const sql = require('./sql');
+const protected_session = require('./protected_session');
+const Note = require('../entities/note');
+const NoteRevision = require('../entities/note_revision');
+const NoteTree = require('../entities/note_tree');
+const Attribute = require('../entities/attribute');
+
+class Repository {
+    constructor(dataKey) {
+        this.dataKey = protected_session.getDataKey(dataKey);
+    }
+
+    async getEntities(query, params = []) {
+        const rows = await sql.getRows(query, params);
+
+        for (const row of rows) {
+            row.dataKey = this.dataKey;
+        }
+
+        return rows.map(row => this.createEntityFromRow(row));
+    }
+
+    async getEntity(query, params = []) {
+        const row = await sql.getRowOrNull(query, params);
+
+        if (!row) {
+            return null;
+        }
+
+        row.dataKey = this.dataKey;
+
+        return this.createEntityFromRow(row);
+    }
+
+    async getNote(noteId) {
+        return await this.getEntity("SELECT * FROM notes WHERE noteId = ?", [noteId]);
+    }
+
+    createEntityFromRow(row) {
+        let entity;
+
+        if (row.attributeId) {
+            entity = new Attribute(this, row);
+        }
+        else if (row.noteRevisionId) {
+            entity = new NoteRevision(this, row);
+        }
+        else if (row.noteTreeId) {
+            entity = new NoteTree(this, row);
+        }
+        else if (row.noteId) {
+            entity = new Note(this, row);
+        }
+        else {
+            throw new Error('Unknown entity type for row: ' + JSON.stringify(row));
+        }
+
+        return entity;
+    }
+}
+
+module.exports = Repository;
\ No newline at end of file
diff --git a/src/services/script_context.js b/src/services/script_context.js
index a6bddba48..98edb6a77 100644
--- a/src/services/script_context.js
+++ b/src/services/script_context.js
@@ -5,17 +5,19 @@ const attributes = require('./attributes');
 const date_notes = require('./date_notes');
 const sql = require('./sql');
 const sync_table = require('./sync_table');
+const Repository = require('./repository');
 
 function ScriptContext(noteId, dataKey) {
     this.scriptNoteId = noteId;
     this.dataKey = protected_session.getDataKey(dataKey);
+    this.repository = new Repository(dataKey);
 
     function serializePayload(payload) {
         return JSON.stringify(payload, null, '\t');
     }
 
     this.getNoteById = async function(noteId) {
-        return notes.getNoteById(noteId, this.dataKey);
+        return this.repository.getNote(noteId);
     };
 
     this.getNotesWithAttribute = async function (attrName, attrValue) {
@@ -60,7 +62,7 @@ function ScriptContext(noteId, dataKey) {
     };
 
     this.updateNote = async function (note) {
-        if (note.type === 'code' && note.mime === 'application/json') {
+        if (note.isJson()) {
             note.content = serializePayload(note.jsonContent);
         }
 
diff --git a/src/services/sql.js b/src/services/sql.js
index cbbd732d4..8b52df374 100644
--- a/src/services/sql.js
+++ b/src/services/sql.js
@@ -6,10 +6,6 @@ const fs = require('fs');
 const sqlite = require('sqlite');
 const app_info = require('./app_info');
 const resource_dir = require('./resource_dir');
-const Note = require('../entities/note');
-const NoteRevision = require('../entities/note_revision');
-const NoteTree = require('../entities/note_tree');
-const Attribute = require('../entities/attribute');
 
 async function createConnection() {
     return await sqlite.open(dataDir.DOCUMENT_PATH, {Promise});
@@ -137,45 +133,6 @@ async function getRows(query, params = []) {
     return await wrap(async db => db.all(query, ...params));
 }
 
-async function getEntities(query, params = []) {
-    const rows = await getRows(query, params);
-
-    return rows.map(createEntityFromRow);
-}
-
-async function getEntity(query, params = []) {
-    const row = await getRowOrNull(query, params);
-
-    if (!row) {
-        return null;
-    }
-
-    return createEntityFromRow(row);
-}
-
-function createEntityFromRow(row) {
-    let entity;
-    let sql = module.exports;
-
-    if (row.attributeId) {
-        entity = new Attribute(sql, row);
-    }
-    else if (row.noteRevisionId) {
-        entity = new NoteRevision(sql, row);
-    }
-    else if (row.noteTreeId) {
-        entity = new NoteTree(sql, row);
-    }
-    else if (row.noteId) {
-        entity = new Note(sql, row);
-    }
-    else {
-        throw new Error('Unknown entity type for row: ' + JSON.stringify(row));
-    }
-
-    return entity;
-}
-
 async function getMap(query, params = []) {
     const map = {};
     const results = await getRows(query, params);
@@ -309,8 +266,6 @@ module.exports = {
     getRow,
     getRowOrNull,
     getRows,
-    getEntities,
-    getEntity,
     getMap,
     getColumn,
     execute,