diff --git a/common/python/connectors/common/__init__.py b/common/python/connectors/common/__init__.py
new file mode 100644
index 000000000..c71b194f4
--- /dev/null
+++ b/common/python/connectors/common/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2020 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+__all__ = []
diff --git a/common/python/connectors/common/db_helper/__init__.py b/common/python/connectors/common/db_helper/__init__.py
new file mode 100644
index 000000000..c71b194f4
--- /dev/null
+++ b/common/python/connectors/common/db_helper/__init__.py
@@ -0,0 +1,15 @@
+# Copyright 2020 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+__all__ = []
diff --git a/common/python/connectors/common/db_helper/work_order_lmdb_helper.py b/common/python/connectors/common/db_helper/work_order_lmdb_helper.py
new file mode 100644
index 000000000..265b19165
--- /dev/null
+++ b/common/python/connectors/common/db_helper/work_order_lmdb_helper.py
@@ -0,0 +1,164 @@
+# Copyright 2020 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import time
+import json
+import logging
+from error_code.error_status import WorkOrderStatus
+from error_code.enclave_error import EnclaveError
+
+from jsonrpc.exceptions import JSONRPCDispatchException
+
+logger = logging.getLogger(__name__)
+
+
+class WorkOrderLmdbHelper:
+    """
+    WorkOrderDBHelper helps listener or other client facing modules
+    to interact with the kv storage for queries related to work
+    order processing.
+    """
+# ------------------------------------------------------------------------------------------------
+
+    def __init__(self, kv_helper):
+        """
+        Function to perform init activity
+        Parameters:
+            - kv_helper is a object of shared kv database
+        """
+
+        self.kv_helper = kv_helper
+
+# ---------------------------------------------------------------------------------------------
+    def get_wo_result(self, wo_id):
+        """
+        Function to get work-order result from shared kv database
+        Parameters:
+            - wo_id is the id of the work-order for which result is
+            requested.
+        Returns jrpc response as defined in EEA spec 6.1.2
+        """
+
+        # Work order is processed if it is in wo-response table
+        value = self.kv_helper.get("wo-responses", wo_id)
+        if value:
+            response = json.loads(value)
+            if 'result' in response:
+                return response['result']
+
+            # response without a result should have an error
+            err_code = response["error"]["code"]
+            err_msg = response["error"]["message"]
+            if err_code == EnclaveError.ENCLAVE_ERR_VALUE:
+                err_code = WorkOrderStatus.INVALID_PARAMETER_FORMAT_OR_VALUE
+            elif err_code == EnclaveError.ENCLAVE_ERR_UNKNOWN:
+                err_code = WorkOrderStatus.UNKNOWN_ERROR
+            else:
+                err_code = WorkOrderStatus.FAILED
+            raise JSONRPCDispatchException(err_code, err_msg)
+
+        if(self.kv_helper.get("wo-timestamps", wo_id) is not None):
+            # work order is yet to be processed
+            raise JSONRPCDispatchException(
+                WorkOrderStatus.PENDING,
+                "Work order result is yet to be updated")
+
+        # work order not in 'wo-timestamps' table
+        raise JSONRPCDispatchException(
+            WorkOrderStatus.INVALID_PARAMETER_FORMAT_OR_VALUE,
+            "Work order Id not found in the database. Hence invalid parameter")
+
+# ---------------------------------------------------------------------------------------------
+    def submit_wo(self, wo_id, input_json_str):
+        """
+        Function to submit and store a new work-order
+        Parameters:
+            - wo_id: id of work-order being submitted
+            - input_json_str: The actual work-order as received
+            from the requester
+        """
+
+        if(self.kv_helper.get("wo-timestamps", wo_id) is None):
+
+            # Create a new work order entry.
+            # Don't change the order of table updation.
+            # The order is important for clean up if the TCS is restarted in
+            # the middle.
+            epoch_time = str(time.time())
+
+            # Update the tables
+            self.kv_helper.set("wo-timestamps", wo_id, epoch_time)
+            self.kv_helper.set("wo-requests", wo_id, input_json_str)
+            self.kv_helper.set("wo-scheduled", wo_id, input_json_str)
+
+            raise JSONRPCDispatchException(
+                WorkOrderStatus.PENDING,
+                "Work order is computing. Please query for WorkOrderGetResult \
+                 to view the result")
+
+        # Workorder id already exists
+        raise JSONRPCDispatchException(
+            WorkOrderStatus.INVALID_PARAMETER_FORMAT_OR_VALUE,
+            "Work order id already exists in the database. \
+                Hence invalid parameter")
+
+    def clear_a_processed_wo(self):
+        """
+        Function to clears one(least recently added) processed
+        work-order from wo-processed table
+        """
+        work_orders = self.kv_helper.lookup("wo-timestamps")
+        for id in work_orders:
+
+            # If work order is processed then remove from table
+            if (self.kv_helper.get("wo-processed", id) is not None):
+                self.kv_helper.remove("wo-processed", id)
+                self.kv_helper.remove("wo-requests", id)
+                self.kv_helper.remove("wo-responses", id)
+                self.kv_helper.remove("wo-receipts", id)
+                self.kv_helper.remove("wo-timestamps", id)
+                return id
+
+    def cleanup_hindered_wo(self):
+        """
+        This function is meant to do a boot time cleanup
+        Returns the list of work-order to be processed and the count
+        """
+        workorder_count = 0
+        workorder_list = []
+        work_orders = self.kv_helper.lookup("wo-timestamps")
+        for wo_id in work_orders:
+
+            if (self.kv_helper.get("wo-scheduled", wo_id) is None and
+                    self.kv_helper.get("wo-processing", wo_id) is None and
+                    self.kv_helper.get("wo-processed", wo_id) is None):
+
+                if (self.kv_helper.get("wo-requests", wo_id) is not None):
+                    self.kv_helper.remove("wo-requests", wo_id)
+
+                if (self.kv_helper.get("wo-responses", wo_id) is not None):
+                    self.kv_helper.remove("wo-responses", wo_id)
+
+                if (self.kv_helper.get("wo-receipts", wo_id) is not None):
+                    self.kv_helper.remove("wo-receipts", wo_id)
+
+                self.kv_helper.remove("wo-timestamps", wo_id)
+
+            else:
+                # Add to the internal FIFO
+                workorder_list.append(wo_id)
+                workorder_count += 1
+
+        return workorder_list, workorder_count
+# ---------------------------------------------------------------------------------------------
diff --git a/common/python/connectors/common/db_helper/worker_encryption_key_lmdb_helper.py b/common/python/connectors/common/db_helper/worker_encryption_key_lmdb_helper.py
new file mode 100644
index 000000000..36100f56a
--- /dev/null
+++ b/common/python/connectors/common/db_helper/worker_encryption_key_lmdb_helper.py
@@ -0,0 +1,47 @@
+# Copyright 2020 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class WorkerEncryptionKeyLmdbHelper:
+    """
+    WorkerEncryptionKeyDBHelper helps listener or other client
+    facing modules to interact with the kv storage for queries
+    related to encryption key. It implements all low level db
+    calls which aides in the logical flows for getting/setting
+    encryption keys.
+    """
+# ------------------------------------------------------------------------------------------------
+
+    def __init__(self, kv_helper):
+        """
+        Function to perform init activity
+        Parameters:
+            - kv_helper is a object of lmdb database
+        """
+        self.kv_helper = kv_helper
+
+# ---------------------------------------------------------------------------------------------
+    def get_worker_with_id(self, worker_id):
+        """
+        Function to get worker corresponding to supplied worker id
+        Parameters:
+            - worker_id: id of worker being looked for
+        Returns worker corresponding to key
+        """
+
+        return self.kv_helper.get_worker("workers", worker_id)
diff --git a/common/python/connectors/common/db_helper/worker_registry_lmdb_helper.py b/common/python/connectors/common/db_helper/worker_registry_lmdb_helper.py
new file mode 100644
index 000000000..8f782e5e0
--- /dev/null
+++ b/common/python/connectors/common/db_helper/worker_registry_lmdb_helper.py
@@ -0,0 +1,82 @@
+# Copyright 2020 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class WorkerRegistryLmdbHelper:
+    """
+    WorkerRegistryDBHelper helps listener or other client facing modules
+    to interact with the kv storage for queries related to worker registry.
+    """
+# ------------------------------------------------------------------------------------------------
+
+    def __init__(self, kv_helper):
+        """
+        Function to perform init activity
+        Parameters:
+            - kv_helper is a object of lmdb database
+        """
+
+        self.kv_helper = kv_helper
+# ------------------------------------------------------------------------------------------------
+
+    def get_worker_with_id(self, worker_id):
+        """
+        Function to get worker corresponding to supplied worker id
+        Parameters:
+            - worker_id: id of worker being looked for
+        Returns worker corresponding to key
+        """
+        return self.kv_helper.get("workers", worker_id)
+
+# ------------------------------------------------------------------------------------------------
+
+    def save_worker(self, worker_id, worker_details):
+        """
+        Function to save a worker with given id and details
+        Parameters:
+            - worker_id: id of worker to be saved
+            - worker_details: Details of worker to be saved
+        """
+        self.kv_helper.set("workers", worker_id, worker_details)
+
+# ------------------------------------------------------------------------------------------------
+    def get_all_workers(self):
+        """
+        Function to retrieve all workers from database
+        Returns a list of all workers in the 'workers' table
+        """
+        return self.kv_helper.lookup("workers")
+# ------------------------------------------------------------------------------------------------
+
+    def cleanup_registries(self):
+        """
+        Function to clean up all registries from the database
+        """
+        organisation_id = self.kv_helper.lookup("registries")
+        for o_id in organisation_id:
+            self.kv_helper.remove("registries", o_id)
+# ------------------------------------------------------------------------------------------------
+
+    def save_registry(self, reg_id, registry_details):
+        """
+        Function to save/create a new registry in the database
+        Parameters:
+            - reg_id: Id of registry to be saved/updated
+            - registry_details: Details of new/updated registry
+        """
+        return self.kv_helper.set("registries", reg_id, registry_details)
diff --git a/common/python/connectors/common/db_helper/workorder_receipt_lmdb_helper.py b/common/python/connectors/common/db_helper/workorder_receipt_lmdb_helper.py
new file mode 100644
index 000000000..7d40a8390
--- /dev/null
+++ b/common/python/connectors/common/db_helper/workorder_receipt_lmdb_helper.py
@@ -0,0 +1,180 @@
+# Copyright 2020 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import json
+import logging
+from error_code.error_status import ReceiptCreateStatus, SignatureStatus,\
+    JRPCErrorCodes
+from jsonrpc.exceptions import JSONRPCDispatchException
+
+logger = logging.getLogger(__name__)
+
+
+class WorkOrderReceiptLmdbHelper:
+    """
+    WorkOrderReceiptDBHelper helps listener or other client facing modules
+    to interact with the kv storage for queries related to work order
+    receipts' processing.
+    """
+# -----------------------------------------------------------------------------
+
+    def __init__(self, kv_helper):
+        """
+        Function to perform init activity
+        Parameters:
+            - kv_helper is a object of lmdb database
+        """
+        # Special index 0xFFFFFFFF value to fetch last update to receipt
+        self.LAST_RECEIPT_INDEX = 1 << 32
+        self.kv_helper = kv_helper
+
+# -----------------------------------------------------------------------------
+    def get_wo_req(self, wo_id):
+        """
+        Function to get a work-order request
+        Parameters:
+            - wo_id: work-order id
+        Return the work-order request corresponding to the id
+        """
+        return self.kv_helper.get("wo-requests", wo_id)
+
+# -----------------------------------------------------------------------------
+
+    def get_wo_receipt(self, wo_id):
+        """
+        Function to get a work-order receipt
+        Parameters:
+            - wo_id: work-order id
+        Return the work-order receipt corresponding to the id
+        """
+        return self.kv_helper.get("wo-receipts", wo_id)
+
+# -----------------------------------------------------------------------------
+
+    def save_wo_receipt(self, wo_id, input_str):
+        """
+        Function to save a work-order receipt in the database
+        Parameters:
+            - wo_id: id of work-order
+            - input_str: the actual receipt
+        """
+        self.kv_helper.set("wo-receipts", wo_id, input_str)
+
+# -----------------------------------------------------------------------------
+
+    def get_wo_receipt_update(self, wo_id):
+        """
+        Function to get work-order receipt updates
+        Parameters:
+            - wo_id: id of work-order for which receipt updates are required
+        Returns the receipt update for corresponding id
+        """
+        return self.kv_helper.get("wo-receipt-updates", wo_id)
+
+# -----------------------------------------------------------------------------
+
+    def save_receipt_update(self, wo_id, updated_receipt):
+        """
+        Function to save work-order receipt updates
+        Parameters:
+            - wo_id: id of work-order for which receipt updates are intended
+            - updated_receipt: the content of the updated receipt to be stored
+        """
+        self.kv_helper.set("wo-receipt-updates", wo_id, updated_receipt)
+
+# -----------------------------------------------------------------------------
+
+    def retrieve_wo_receipt(self, wo_id):
+        """
+        Function to retrieve details of work-order receipt
+        Parameters:
+            - wo_id: id of work-order for which receipt details
+             are required
+        Returns details of a receipt
+        """
+        value = self.kv_helper.get("wo-receipts", wo_id)
+        if value:
+            receipt = json.loads(value)
+            receipt_updates = self.kv_helper.get("wo-receipt-updates", wo_id)
+            if receipt_updates is None:
+                receipt["params"]["receiptCurrentStatus"] = \
+                    receipt["params"]["receiptCreateStatus"]
+            else:
+                receipt_updates_json = json.loads(receipt_updates)
+                # Get the recent update to receipt
+                last_receipt = receipt_updates_json[len(receipt_updates_json)
+                                                    - 1]
+                receipt["params"]["receiptCurrentStatus"] = \
+                    last_receipt["updateType"]
+            return receipt["params"]
+        else:
+            raise JSONRPCDispatchException(
+                JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
+                "Work order receipt for work order id {} not found in the "
+                "database. Hence invalid parameter".format(
+                    wo_id
+                ))
+
+# -----------------------------------------------------------------------------
+
+    def retrieve_wo_receipt_update(self, wo_id, update_index, updater_id):
+
+        """
+        Function to retrieve a specific(by index) update for a specific
+        updater-id for a work-order id
+        Parameters:
+            - wo_id: id of work-order for which the receipt is being
+            queried
+            - update_index: index of update for this specific receipt
+            - updater_id: id of updater
+        Returns
+        """
+        receipt_updates = self.kv_helper.get("wo-receipt-updates", wo_id)
+
+        if receipt_updates:
+            receipt_updates_json = json.loads(receipt_updates)
+            total_updates = len(receipt_updates_json)
+            if update_index <= 0:
+                raise JSONRPCDispatchException(
+                    JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
+                    "Update index should be positive non-zero number."
+                    " Hence invalid parameter")
+            elif update_index > total_updates:
+                if update_index == self.LAST_RECEIPT_INDEX:
+                    # set to the index of last update to receipt
+                    update_index = total_updates - 1
+                else:
+                    raise JSONRPCDispatchException(
+                        JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
+                        "Update index is larger than total update count."
+                        " Hence invalid parameter")
+            else:
+                # If the index is less than total updates
+                # then decrement by one since it is zero based array
+                update_index = update_index - 1
+            update_to_receipt = receipt_updates_json[update_index]
+            # If updater id is present then check whether it matches
+            if updater_id:
+                if update_to_receipt["updaterId"] != updater_id:
+                    raise JSONRPCDispatchException(
+                        JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
+                        "Update index and updater id doesn't match."
+                        " Hence invalid parameter")
+            update_to_receipt["updateCount"] = total_updates
+            return update_to_receipt
+        else:
+            raise JSONRPCDispatchException(
+                JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
+                "There is no updates available to this receipt."
+                " Hence invalid parameter")
diff --git a/listener/avalon_listener/tcs_work_order_handler.py b/listener/avalon_listener/tcs_work_order_handler.py
index 7e4f88f68..8dbd5a04a 100644
--- a/listener/avalon_listener/tcs_work_order_handler.py
+++ b/listener/avalon_listener/tcs_work_order_handler.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import time
 import json
 import logging
 from error_code.error_status import WorkOrderStatus
@@ -21,6 +20,8 @@
 from avalon_sdk.work_order.work_order_request_validator \
     import WorkOrderRequestValidator
 from utility.hex_utils import is_valid_hex_str
+from connectors.common.db_helper.work_order_lmdb_helper \
+    import WorkOrderLmdbHelper
 
 from jsonrpc.exceptions import JSONRPCDispatchException
 
@@ -51,7 +52,7 @@ def __init__(self, kv_helper, max_wo_count):
             - kv_helper is a object of lmdb database
         """
 
-        self.kv_helper = kv_helper
+        self.db_helper = WorkOrderLmdbHelper(kv_helper)
         self.workorder_count = 0
         self.max_workorder_count = max_wo_count
         self.workorder_list = []
@@ -64,31 +65,10 @@ def __work_order_handler_on_boot(self):
         Function to perform on-boot process of work order handler
         """
 
-        work_orders = self.kv_helper.lookup("wo-timestamps")
-        for wo_id in work_orders:
+        self.workorder_list, self.workorder_count = \
+            self.db_helper.cleanup_hindered_wo()
 
-            if(self.kv_helper.get("wo-scheduled", wo_id) is None and
-                    self.kv_helper.get("wo-processing", wo_id) is None and
-                    self.kv_helper.get("wo-processed", wo_id) is None):
-
-                if(self.kv_helper.get("wo-requests", wo_id) is not None):
-                    self.kv_helper.remove("wo-requests", wo_id)
-
-                if(self.kv_helper.get("wo-responses", wo_id) is not None):
-                    self.kv_helper.remove("wo-responses", wo_id)
-
-                if(self.kv_helper.get("wo-receipts", wo_id) is not None):
-                    self.kv_helper.remove("wo-receipts", wo_id)
-
-                # TODO: uncomment after fixing lmbd error
-                self.kv_helper.remove("wo-timestamps", wo_id)
-
-            else:
-                # Add to the internal FIFO
-                self.workorder_list.append(wo_id)
-                self.workorder_count += 1
-
-# ---------------------------------------------------------------------------------------------
+    # ---------------------------------------------------------------------------------------------
     def WorkOrderGetResult(self, **params):
         """
         Function to process work order get result
@@ -105,35 +85,7 @@ def WorkOrderGetResult(self, **params):
                 JsonRpcErrorCode.INVALID_PARAMETER,
                 "Invalid work order Id"
             )
-
-        # Work order is processed if it is in wo-response table
-        value = self.kv_helper.get("wo-responses", wo_id)
-        if value:
-            response = json.loads(value)
-            if 'result' in response:
-                return response['result']
-
-            # response without a result should have an error
-            err_code = response["error"]["code"]
-            err_msg = response["error"]["message"]
-            if err_code == EnclaveError.ENCLAVE_ERR_VALUE:
-                err_code = WorkOrderStatus.INVALID_PARAMETER_FORMAT_OR_VALUE
-            elif err_code == EnclaveError.ENCLAVE_ERR_UNKNOWN:
-                err_code = WorkOrderStatus.UNKNOWN_ERROR
-            else:
-                err_code = WorkOrderStatus.FAILED
-            raise JSONRPCDispatchException(err_code, err_msg)
-
-        if(self.kv_helper.get("wo-timestamps", wo_id) is not None):
-            # work order is yet to be processed
-            raise JSONRPCDispatchException(
-                WorkOrderStatus.PENDING,
-                "Work order result is yet to be updated")
-
-        # work order not in 'wo-timestamps' table
-        raise JSONRPCDispatchException(
-            WorkOrderStatus.INVALID_PARAMETER_FORMAT_OR_VALUE,
-            "Work order Id not found in the database. Hence invalid parameter")
+        return self.db_helper.get_wo_result(wo_id)
 
 # ---------------------------------------------------------------------------------------------
     def WorkOrderSubmit(self, **params):
@@ -182,20 +134,10 @@ def WorkOrderSubmit(self, **params):
         if((self.workorder_count + 1) > self.max_workorder_count):
 
             # if max count reached clear a processed entry
-            work_orders = self.kv_helper.lookup("wo-timestamps")
-            for id in work_orders:
-
-                # If work order is processed then remove from table
-                if(self.kv_helper.get("wo-processed", id) is not None):
-                    self.kv_helper.remove("wo-processed", id)
-                    self.kv_helper.remove("wo-requests", id)
-                    self.kv_helper.remove("wo-responses", id)
-                    self.kv_helper.remove("wo-receipts", id)
-                    self.kv_helper.remove("wo-timestamps", id)
-
-                    self.workorder_list.remove(id)
-                    self.workorder_count -= 1
-                    break
+            removed_wo = self.db_helper.clear_a_processed_wo()
+            if(removed_wo is not None):
+                self.workorder_list.remove()
+                self.workorder_count -= 1
 
             # If no work order is processed then return busy
             if((self.workorder_count + 1) > self.max_workorder_count):
@@ -203,31 +145,6 @@ def WorkOrderSubmit(self, **params):
                     WorkOrderStatus.BUSY,
                     "Work order handler is busy updating the result")
 
-        if(self.kv_helper.get("wo-timestamps", wo_id) is None):
-
-            # Create a new work order entry.
-            # Don't change the order of table updation.
-            # The order is important for clean up if the TCS is restarted in
-            # the middle.
-            epoch_time = str(time.time())
-
-            # Update the tables
-            self.kv_helper.set("wo-timestamps", wo_id, epoch_time)
-            self.kv_helper.set("wo-requests", wo_id, input_json_str)
-            self.kv_helper.set("wo-scheduled", wo_id, input_json_str)
-            # Add to the internal FIFO
-            self.workorder_list.append(wo_id)
-            self.workorder_count += 1
-
-            raise JSONRPCDispatchException(
-                WorkOrderStatus.PENDING,
-                "Work order is computing. Please query for WorkOrderGetResult \
-                 to view the result")
-
-        # Workorder id already exists
-        raise JSONRPCDispatchException(
-            WorkOrderStatus.INVALID_PARAMETER_FORMAT_OR_VALUE,
-            "Work order id already exists in the database. \
-                Hence invalid parameter")
+        self.db_helper.submit_wo(wo_id, input_json_str)
 
 # ---------------------------------------------------------------------------------------------
diff --git a/listener/avalon_listener/tcs_worker_encryption_key_handler.py b/listener/avalon_listener/tcs_worker_encryption_key_handler.py
index bf5cb7e32..7fdf18ed2 100644
--- a/listener/avalon_listener/tcs_worker_encryption_key_handler.py
+++ b/listener/avalon_listener/tcs_worker_encryption_key_handler.py
@@ -18,6 +18,8 @@
 from error_code.error_status import WorkerError
 
 from jsonrpc.exceptions import JSONRPCDispatchException
+from connectors.common.db_helper.worker_encryption_key_lmdb_helper \
+    import WorkerEncryptionKeyLmdbHelper
 
 logger = logging.getLogger(__name__)
 # No of bytes of encryptionKeyNonce to encrypt data
@@ -48,7 +50,7 @@ def __init__(self, kv_helper):
             - kv_helper is a object of lmdb database
         """
 
-        self.kv_helper = kv_helper
+        self.db_helper = WorkerEncryptionKeyLmdbHelper(kv_helper)
 
 # ---------------------------------------------------------------------------------------------
     def EncryptionKeySet(self, **params):
@@ -73,7 +75,7 @@ def EncryptionKeyGet(self, **params):
         """
 
         worker_id = str(params['workerId'])
-        value = self.kv_helper.get("workers", worker_id)
+        value = self.db_helper.get_worker_with_id(worker_id)
 
         if value is None:
             raise JSONRPCDispatchException(
diff --git a/listener/avalon_listener/tcs_worker_registry_handler.py b/listener/avalon_listener/tcs_worker_registry_handler.py
index 1db2b50e8..221d86a8a 100644
--- a/listener/avalon_listener/tcs_worker_registry_handler.py
+++ b/listener/avalon_listener/tcs_worker_registry_handler.py
@@ -19,6 +19,9 @@
 
 from jsonrpc.exceptions import JSONRPCDispatchException
 
+from connectors.common.db_helper.worker_registry_lmdb_helper \
+    import WorkerRegistryLmdbHelper
+
 logger = logging.getLogger(__name__)
 
 
@@ -51,7 +54,7 @@ def __init__(self, kv_helper):
             - kv_helper is a object of lmdb database
         """
 
-        self.kv_helper = kv_helper
+        self.db_helper = WorkerRegistryLmdbHelper(kv_helper)
         self.worker_pool = []
         self.__worker_registry_handler_on_boot()
 # ------------------------------------------------------------------------------------------------
@@ -62,13 +65,11 @@ def __worker_registry_handler_on_boot(self):
         """
 
         worker_list = []
-        worker_list = self.kv_helper.lookup("workers")
+        worker_list = self.db_helper.get_all_workers()
 
         # Initial Worker details are loaded
         self.worker_pool = worker_list
-        organisation_id = self.kv_helper.lookup("registries")
-        for o_id in organisation_id:
-            self.kv_helper.remove("registries", o_id)
+        self.db_helper.cleanup_registries()
 
         # Adding a new entry that corresponds to this handler, its URI, etc.
         # json with byte32 orgID, string uri, byte32 scAddr,
@@ -83,7 +84,7 @@ def __worker_registry_handler_on_boot(self):
         response = {}
         response['id'] = "regid"
 
-        set_response = self.kv_helper.set("registries", "regid", value)
+        set_response = self.db_helper.save_registry("regid", value)
         if set_response:
             response['result'] = "WorkerRegistryHandleronBoot Successful"
             response['error'] = {}
@@ -92,12 +93,12 @@ def __worker_registry_handler_on_boot(self):
             response['error'] = {}
             response['error']['code'] = WorkerError.UNKNOWN_ERROR
             response['error']['message'] = 'Unknown Error occurred during' + \
-                'worker registry handler boot up'
+                                           'worker registry handler boot up'
 
         return response
-# ------------------------------------------------------------------------------------------------
 
 # ------------------------------------------------------------------------------------------------
+
     def WorkerRegister(self, **params):
         """
         Function to register a new worker to the enclave
@@ -107,8 +108,8 @@ def WorkerRegister(self, **params):
         """
 
         worker_id = must_get_worker_id(params)
-
-        if(self.kv_helper.get("workers", worker_id) is not None):
+        worker = self.db_helper.get_worker_with_id(worker_id)
+        if (worker is not None):
             raise JSONRPCDispatchException(
                 WorkerError.INVALID_PARAMETER_FORMAT_OR_VALUE,
                 "Worker Id already exists in the database." +
@@ -118,7 +119,7 @@ def WorkerRegister(self, **params):
         params["status"] = WorkerStatus.ACTIVE
 
         input_json_str = json.dumps(params)
-        self.kv_helper.set("workers", worker_id, input_json_str)
+        self.db_helper.save_worker(worker_id, input_json_str)
 
         raise JSONRPCDispatchException(
             WorkerError.SUCCESS, "Successfully Registered")
@@ -154,7 +155,7 @@ def WorkerSetStatus(self, **params):
 
         worker_id = must_get_worker_id(params)
 
-        value = self.kv_helper.get("workers", worker_id)
+        value = self.db_helper.get_worker_with_id(worker_id)
         if value:
             json_dict = json.loads(value)
             if not self.__validate_input_worker_status(params):
@@ -164,7 +165,7 @@ def WorkerSetStatus(self, **params):
 
             json_dict['status'] = params['status']
             value = json.dumps(json_dict)
-            self.kv_helper.set("workers", worker_id, value)
+            self.db_helper.save_worker(worker_id, value)
 
             raise JSONRPCDispatchException(
                 WorkerError.SUCCESS,
@@ -177,7 +178,7 @@ def WorkerSetStatus(self, **params):
 # ------------------------------------------------------------------------------------------------
     def __lookup_basic(self, is_lookup_next, params):
         # sync the work pool to that of DB
-        self.worker_pool = self.kv_helper.lookup("workers")
+        self.worker_pool = self.db_helper.get_all_workers()
 
         total_count = 0
         ids = []
@@ -190,7 +191,7 @@ def __lookup_basic(self, is_lookup_next, params):
                 continue
 
             matched = True
-            value = self.kv_helper.get("workers", worker_id)
+            value = self.db_helper.get_worker_with_id(worker_id)
             if value:
                 worker = json.loads(value)
                 criteria = ["workerType", "organizationId",
@@ -250,7 +251,7 @@ def WorkerRetrieve(self, **params):
         worker_id = must_get_worker_id(params)
         # value retrieved is 'result' field as per Spec 5.3.8 Worker Retrieve
         # Response Payload
-        value = self.kv_helper.get("workers", worker_id)
+        value = self.db_helper.get_worker_with_id(worker_id)
 
         if value is None:
             raise JSONRPCDispatchException(
@@ -282,7 +283,7 @@ def WorkerUpdate(self, **params):
 
         # value retrieved is 'result' field as per Spec 5.3.8 Worker Retrieve
         # Response Payload
-        value = self.kv_helper.get("workers", worker_id)
+        value = self.db_helper.get_worker_with_id(worker_id)
 
         if value is None:
             raise JSONRPCDispatchException(
@@ -295,7 +296,7 @@ def WorkerUpdate(self, **params):
             json_dict["details"][item] = worker_details[item]
 
         value = json.dumps(json_dict)
-        self.kv_helper.set("workers", worker_id, value)
+        self.db_helper.save_worker(worker_id, value)
 
         raise JSONRPCDispatchException(
             WorkerError.SUCCESS, "Successfully Updated")
diff --git a/listener/avalon_listener/tcs_workorder_receipt_handler.py b/listener/avalon_listener/tcs_workorder_receipt_handler.py
index 4f49c5c73..eb62e85b8 100644
--- a/listener/avalon_listener/tcs_workorder_receipt_handler.py
+++ b/listener/avalon_listener/tcs_workorder_receipt_handler.py
@@ -22,6 +22,9 @@
 import crypto_utils.signature as signature
 from jsonrpc.exceptions import JSONRPCDispatchException
 
+from connectors.common.db_helper.workorder_receipt_lmdb_helper \
+    import WorkOrderReceiptLmdbHelper
+
 logger = logging.getLogger(__name__)
 
 
@@ -42,10 +45,8 @@ def __init__(self, kv_helper):
             - kv_helper is a object of lmdb database
         """
 
-        self.kv_helper = kv_helper
+        self.db_helper = WorkOrderReceiptLmdbHelper(kv_helper)
         self.__workorder_receipt_on_boot()
-        # Special index 0xFFFFFFFF value to fetch last update to receipt
-        self.LAST_RECEIPT_INDEX = 1 << 32
         # Supported hashing and signing algorithms
         self.SIGNING_ALGORITHM = "SECP256K1"
         self.HASHING_ALGORITHM = "SHA-256"
@@ -73,7 +74,7 @@ def WorkOrderReceiptCreate(self, **params):
         input_json_str = params["raw"]
         input_value = json.loads(input_json_str)
 
-        wo_request = self.kv_helper.get("wo-requests", wo_id)
+        wo_request = self.db_helper.get_wo_req(wo_id)
         if wo_request is None:
             raise JSONRPCDispatchException(
                 JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
@@ -81,13 +82,13 @@ def WorkOrderReceiptCreate(self, **params):
                 "hence invalid request"
             )
         else:
-            wo_receipt = self.kv_helper.get("wo-receipts", wo_id)
+            wo_receipt = self.db_helper.get_wo_receipt(wo_id)
             if wo_receipt is None:
                 status, err_msg = \
                     self.__validate_work_order_receipt_create_req(
                         input_value, wo_request)
                 if status is True:
-                    self.kv_helper.set("wo-receipts", wo_id, input_json_str)
+                    self.db_helper.save_wo_receipt(wo_id, input_json_str)
                     raise JSONRPCDispatchException(
                         JRPCErrorCodes.SUCCESS,
                         "Receipt created successfully"
@@ -104,7 +105,7 @@ def WorkOrderReceiptCreate(self, **params):
                     "Hence invalid parameter"
                 )
 
-# -----------------------------------------------------------------------------
+    # -----------------------------------------------------------------------------
 
     def __validate_work_order_receipt_create_req(self, wo_receipt_req,
                                                  wo_request):
@@ -179,7 +180,7 @@ def WorkOrderReceiptUpdate(self, **params):
         input_value = json.loads(input_json_str)
 
         # Check if receipt for work order id is created or not
-        value = self.kv_helper.get("wo-receipts", wo_id)
+        value = self.db_helper.get_wo_receipt(wo_id)
 
         if value:
             # Receipt is created, validate update receipt request
@@ -188,7 +189,7 @@ def WorkOrderReceiptUpdate(self, **params):
             if status is True:
                 # Load previous updates to receipt
                 updates_to_receipt = \
-                    self.kv_helper.get("wo-receipt-updates", wo_id)
+                    self.db_helper.get_wo_receipt_update(wo_id)
                 # If it is first update to receipt
                 if updates_to_receipt is None:
                     updated_receipt = []
@@ -220,8 +221,8 @@ def WorkOrderReceiptUpdate(self, **params):
                             " is not allowed"
                         )
                 updated_receipt.append(input_value)
-                self.kv_helper.set("wo-receipt-updates", wo_id,
-                                   json.dumps(updated_receipt))
+                self.db_helper.save_receipt_update(wo_id,
+                                                   json.dumps(updated_receipt))
                 raise JSONRPCDispatchException(
                     JRPCErrorCodes.SUCCESS,
                     "Receipt updated successfully"
@@ -366,36 +367,17 @@ def WorkOrderReceiptLookUpNext(self, **params):
 
     def WorkOrderReceiptRetrieve(self, **params):
         """
-        Function to retrieve the details of worker
+        Function to retrieve the details of work-order receipt
         Parameters:
-            - params is variable-length arugment list containing work order
-            receipt request request as defined in EEA spec 7.2.4
+            - params is variable-length argument list containing work order
+            receipt request as defined in EEA spec 7.2.4
         Returns jrpc response as defined in 7.2.5
         """
         wo_id = params["workOrderId"]
-
-        value = self.kv_helper.get("wo-receipts", wo_id)
-        if value:
-            receipt = json.loads(value)
-            receipt_updates = self.kv_helper.get("wo-receipt-updates", wo_id)
-            if receipt_updates is None:
-                receipt["params"]["receiptCurrentStatus"] = \
-                    receipt["params"]["receiptCreateStatus"]
-            else:
-                receipt_updates_json = json.loads(receipt_updates)
-                # Get the recent update to receipt
-                last_receipt = receipt_updates_json[len(receipt_updates_json)
-                                                    - 1]
-                receipt["params"]["receiptCurrentStatus"] = \
-                    last_receipt["updateType"]
-            return receipt["params"]
-        else:
-            raise JSONRPCDispatchException(
-                JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
-                "Work order receipt for work order id {} not found in the "
-                "database. Hence invalid parameter".format(
-                    wo_id
-                ))
+        try:
+            return self.db_helper.retrieve_wo_receipt(wo_id)
+        except JSONRPCDispatchException:
+            raise
 
 # -----------------------------------------------------------------------------
 
@@ -403,7 +385,7 @@ def WorkOrderReceiptUpdateRetrieve(self, **params):
         """
         Function to retrieve the update to work order receipt
         Parameters:
-            - params is variable-length arugment list containing work order
+            - params is variable-length argument list containing work order
             update retrieve request as defined in EEA spec 7.2.6
         Returns:
             Jrpc response as defined in EEA spec 7.2.7
@@ -420,41 +402,9 @@ def WorkOrderReceiptUpdateRetrieve(self, **params):
         # starts from 1
         update_index = input_params["updateIndex"]
         # Load list of updates to the receipt
-        receipt_updates = self.kv_helper.get("wo-receipt-updates", wo_id)
-
-        if receipt_updates:
-            receipt_updates_json = json.loads(receipt_updates)
-            total_updates = len(receipt_updates_json)
-            if update_index <= 0:
-                raise JSONRPCDispatchException(
-                    JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
-                    "Update index should be positive non-zero number."
-                    " Hence invalid parameter")
-            elif update_index > total_updates:
-                if update_index == self.LAST_RECEIPT_INDEX:
-                    # set to the index of last update to receipt
-                    update_index = total_updates - 1
-                else:
-                    raise JSONRPCDispatchException(
-                        JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
-                        "Update index is larger than total update count."
-                        " Hence invalid parameter")
-            else:
-                # If the index is less than total updates
-                # then decrement by one since it is zero based array
-                update_index = update_index - 1
-            update_to_receipt = receipt_updates_json[update_index]
-            # If updater id is present then check whether it matches
-            if updater_id:
-                if update_to_receipt["updaterId"] != updater_id:
-                    raise JSONRPCDispatchException(
-                        JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
-                        "Update index and updater id doesn't match"
-                        " Hence invalid parameter")
-            update_to_receipt["updateCount"] = total_updates
-            return update_to_receipt
-        else:
-            raise JSONRPCDispatchException(
-                JRPCErrorCodes.INVALID_PARAMETER_FORMAT_OR_VALUE,
-                "There is no updates available to this receipt"
-                " Hence invalid parameter")
+        try:
+            return self.db_helper.retrieve_wo_receipt_update(wo_id,
+                                                             update_index,
+                                                             updater_id)
+        except JSONRPCDispatchException:
+            raise