diff --git a/backend-assemblyscript/step-2-json-encoding/assembly/response.ts b/backend-assemblyscript/step-2-json-encoding/assembly/response.ts
index 0b07521..4bae8cb 100644
--- a/backend-assemblyscript/step-2-json-encoding/assembly/response.ts
+++ b/backend-assemblyscript/step-2-json-encoding/assembly/response.ts
@@ -34,17 +34,17 @@ export class UnknownResponse extends Response {
 }
 
 export class PostResponse extends Response {
-    numberOfTwits: i32;
-    constructor(numberOfTwits: i32) {
+    msgCount: i32;
+    constructor(msgCount: i32) {
         super();
-        this.numberOfTwits = numberOfTwits;
+        this.msgCount = msgCount;
     }
 
     serialize(): string {
         let encoder = new JSONEncoder();
         encoder.pushObject(null);
         encoder.setString("action", "Post");
-        encoder.setInteger("number_of_twits", this.numberOfTwits);
+        encoder.setInteger("count", this.msgCount);
         encoder.popObject();
 
         return encoder.toString();
@@ -52,20 +52,20 @@ export class PostResponse extends Response {
 }
 
 export class FetchResponse extends Response {
-    messageList: Array<string>;
+    posts: Array<string>;
 
-    constructor(messageList: Array<string>) {
+    constructor(posts: Array<string>) {
         super();
-        this.messageList = messageList;
+        this.posts = posts;
     }
 
     serialize(): string {
         let encoder = new JSONEncoder();
         encoder.pushObject(null);
         encoder.setString("action", "Fetch");
-        encoder.pushArray("msg_list");
-        for (let i = 0; i < this.messageList.length; i++) {
-            let message = this.messageList[i];
+        encoder.pushArray("posts");
+        for (let i = 0; i < this.posts.length; i++) {
+            let message = this.posts[i];
             encoder.pushObject(null);
             encoder.setString("msg", message);
             encoder.popObject();
diff --git a/backend-assemblyscript/step-3-internal-storage/assembly/main.ts b/backend-assemblyscript/step-3-internal-storage/assembly/main.ts
index 7e74b78..9a35470 100644
--- a/backend-assemblyscript/step-3-internal-storage/assembly/main.ts
+++ b/backend-assemblyscript/step-3-internal-storage/assembly/main.ts
@@ -1,7 +1,7 @@
 import {Action, decode, FetchRequest, PostRequest} from "./request";
 import {PostResponse, Message, FetchResponse, UnknownResponse} from "./response";
 
-let messageList: Array<Message> = new Array<Message>();
+let posts: Array<Message> = new Array<Message>();
 
 // main handler for an application
 export function handler(input: string): string {
@@ -10,19 +10,19 @@ export function handler(input: string): string {
 
   if (request.action == Action.Post) {
     let post = request as PostRequest;
-    messageList.push(new Message(post.msg, post.handle));
-    let response = new PostResponse(messageList.length);
+    posts.push(new Message(post.msg, post.handle));
+    let response = new PostResponse(posts.length);
     return response.serialize()
   } else if (request.action == Action.Fetch) {
     let fetch = request as FetchRequest;
     var messages: Array<Message>;
     if (fetch.filter_handle == null) {
-      messages = messageList
+      messages = posts
     } else {
       let filter_handle = fetch.filter_handle as string;
       let filtered = new Array<Message>();
-      for (let i = 0; i < messageList.length; i++) {
-        let message = messageList[i];
+      for (let i = 0; i < posts.length; i++) {
+        let message = posts[i];
         if (message.handle == filter_handle) {
           filtered.push(message)
         }
diff --git a/backend-assemblyscript/step-3-internal-storage/assembly/response.ts b/backend-assemblyscript/step-3-internal-storage/assembly/response.ts
index 2be541b..88236a9 100644
--- a/backend-assemblyscript/step-3-internal-storage/assembly/response.ts
+++ b/backend-assemblyscript/step-3-internal-storage/assembly/response.ts
@@ -34,17 +34,17 @@ export class UnknownResponse extends Response {
 }
 
 export class PostResponse extends Response {
-    numberOfTwits: i32;
-    constructor(numberOfTwits: i32) {
+    msgCount: i32;
+    constructor(msgCount: i32) {
         super();
-        this.numberOfTwits = numberOfTwits;
+        this.msgCount = msgCount;
     }
 
     serialize(): string {
         let encoder = new JSONEncoder();
         encoder.pushObject(null);
         encoder.setString("action", "Post");
-        encoder.setInteger("number_of_twits", this.numberOfTwits);
+        encoder.setInteger("count", this.msgCount);
         encoder.popObject();
 
         return encoder.toString();
@@ -52,20 +52,20 @@ export class PostResponse extends Response {
 }
 
 export class FetchResponse extends Response {
-    messageList: Array<Message>;
+    posts: Array<Message>;
 
-    constructor(messageList: Array<Message>) {
+    constructor(posts: Array<Message>) {
         super();
-        this.messageList = messageList;
+        this.posts = posts;
     }
 
     serialize(): string {
         let encoder = new JSONEncoder();
         encoder.pushObject(null);
         encoder.setString("action", "Fetch");
-        encoder.pushArray("message_list");
-        for (let i = 0; i < this.messageList.length; i++) {
-            let twit = this.messageList[i];
+        encoder.pushArray("posts");
+        for (let i = 0; i < this.posts.length; i++) {
+            let twit = this.posts[i];
             encoder.pushObject(null);
             encoder.setString("msg", twit.msg);
             encoder.setString("handle", twit.handle);
diff --git a/backend-assemblyscript/step-4-sqlite/assembly/database.ts b/backend-assemblyscript/step-4-sqlite/assembly/database.ts
index 0e231ad..63d2abe 100644
--- a/backend-assemblyscript/step-4-sqlite/assembly/database.ts
+++ b/backend-assemblyscript/step-4-sqlite/assembly/database.ts
@@ -1,5 +1,5 @@
 import {log} from "../node_modules/assemblyscript-sdk/assembly/logger";
-import {query} from "../node_modules/db-connector/assembly/index"
+import {query} from "../node_modules/db-connector/assembly/sqlite"
 
 function doRequest(request: string): string {
 
@@ -23,8 +23,18 @@ export function addMessage(msg: string, handle: string): void {
     doRequest(request);
 }
 
-export function getMessages(): string {
-    let request = "SELECT * FROM messages";
-    let result = doRequest(request);
-    return result;
+export function getMessages(handle: string | null): string {
+    if (handle) {
+        let request = 'SELECT json_group_array(json_object("msg", msg, "handle", handle)) AS json_result FROM (SELECT * FROM messages WHERE handle = "' + handle + '")';
+        return doRequest(request);
+    } else {
+        let request = "SELECT json_group_array(json_object('msg', msg, 'handle', handle)) AS json_result FROM (SELECT * FROM messages)";
+        return doRequest(request);
+    }
+}
+
+export function getPostsCount(): u32 {
+    let request = "SELECT COUNT(*) from messages";
+    let result = doRequest(request);
+    return U32.parseInt(result);
 }
diff --git a/backend-assemblyscript/step-4-sqlite/assembly/main.ts b/backend-assemblyscript/step-4-sqlite/assembly/main.ts
index d3ef1d7..cd67b92 100644
--- a/backend-assemblyscript/step-4-sqlite/assembly/main.ts
+++ b/backend-assemblyscript/step-4-sqlite/assembly/main.ts
@@ -1,6 +1,6 @@
 import {Action, decode, FetchRequest, PostRequest} from "./request";
 import {PostResponse, Message, FetchResponse, UnknownResponse} from "./response";
-import {addMessage, getMessages, initTables} from "./database";
+import {addMessage, getMessages, getPostsCount, initTables} from "./database";
 
 initTables();
 
@@ -12,29 +12,15 @@ export function handler(input: string): string {
   if (request.action == Action.Post) {
     let post = request as PostRequest;
     addMessage(post.msg, post.handle);
-    let response = new PostResponse(0);
+    let count = getPostsCount();
+
+    let response = new PostResponse(count);
     return response.serialize()
   } else if (request.action == Action.Fetch) {
     let fetch = request as FetchRequest;
 
-    let result = getMessages();
+    let result = getMessages(fetch.handle);
     return result;
-
-    /*if (fetch.filter_handle == null) {
-      messages = messageList
-    } else {
-      let filter_handle = fetch.filter_handle as string;
-      let filtered = new Array<Message>();
-      for (let i = 0; i < messageList.length; i++) {
-        let message = messageList[i];
-        if (message.handle == filter_handle) {
-          filtered.push(message)
-        }
-      }
-      messages = filtered;
-    }
-    let response = new FetchResponse(messages);
-    return response.serialize()*/
   }
 
   let response = new UnknownResponse();
diff --git a/backend-assemblyscript/step-4-sqlite/assembly/request.ts b/backend-assemblyscript/step-4-sqlite/assembly/request.ts
index ead3820..ae2b836 100644
--- a/backend-assemblyscript/step-4-sqlite/assembly/request.ts
+++ b/backend-assemblyscript/step-4-sqlite/assembly/request.ts
@@ -25,12 +25,12 @@ export class PostRequest extends Request {
 }
 
 export class FetchRequest extends Request {
-    public readonly filter_handle: string | null;
+    public readonly handle: string | null;
 
-    constructor(filter_handle: string | null) {
+    constructor(handle: string | null) {
         super();
         this.action = Action.Fetch;
-        this.filter_handle = filter_handle;
+        this.handle = handle;
     }
 }
 
@@ -83,7 +83,6 @@ class RequestJSONEventsHandler extends JSONHandler {
             this.msg = value;
         } else if (name == "handle") {
             this.handle = value;
-        } else if (name == "filter_handle") {
             this.filter_handle = value;
         }
         // json scheme is not strict, so we won't throw an error on excess fields
diff --git a/backend-assemblyscript/step-4-sqlite/assembly/response.ts b/backend-assemblyscript/step-4-sqlite/assembly/response.ts
index 2be541b..56cf3c4 100644
--- a/backend-assemblyscript/step-4-sqlite/assembly/response.ts
+++ b/backend-assemblyscript/step-4-sqlite/assembly/response.ts
@@ -34,17 +34,17 @@ export class UnknownResponse extends Response {
 }
 
 export class PostResponse extends Response {
-    numberOfTwits: i32;
-    constructor(numberOfTwits: i32) {
+    msgCount: u32;
+    constructor(msgCount: u32) {
         super();
-        this.numberOfTwits = numberOfTwits;
+        this.msgCount = msgCount;
     }
 
     serialize(): string {
         let encoder = new JSONEncoder();
         encoder.pushObject(null);
         encoder.setString("action", "Post");
-        encoder.setInteger("number_of_twits", this.numberOfTwits);
+        encoder.setInteger("count", this.msgCount);
         encoder.popObject();
 
         return encoder.toString();
@@ -52,20 +52,20 @@ export class PostResponse extends Response {
 }
 
 export class FetchResponse extends Response {
-    messageList: Array<Message>;
+    posts: Array<Message>;
 
-    constructor(messageList: Array<Message>) {
+    constructor(posts: Array<Message>) {
         super();
-        this.messageList = messageList;
+        this.posts = posts;
     }
 
     serialize(): string {
         let encoder = new JSONEncoder();
         encoder.pushObject(null);
         encoder.setString("action", "Fetch");
-        encoder.pushArray("message_list");
-        for (let i = 0; i < this.messageList.length; i++) {
-            let twit = this.messageList[i];
+        encoder.pushArray("posts");
+        for (let i = 0; i < this.posts.length; i++) {
+            let twit = this.posts[i];
             encoder.pushObject(null);
             encoder.setString("msg", twit.msg);
             encoder.setString("handle", twit.handle);