update en/application-dev/database/database-distributedobject-guidelines.md.

Signed-off-by: Nking_he <6384784@qq.com>

en/application-dev/database/database-distributedobject-guidelines.md

@@ -13,47 +13,47 @@ Call **createDistributedObject()** to create a distributed data object instance.
 
 
 **Table 1** API for creating a distributed data object instance
-| Package| API| Description| 
-| -------- | -------- | -------- |
-| ohos.data.distributedDataObject| createDistributedObject(source: object): DistributedObject | Creates a distributed data object instance for data operations.<br>-&nbsp;**source**: attributes of the **distributedObject** set.<br>-&nbsp;**DistributedObject**: returns the distributed object created.| 
+ | Package | API | Description | 
+ | -------- | -------- | -------- |
+ | ohos.data.distributedDataObject | createDistributedObject(source: object): DistributedObject | Creates a distributed data object instance for data operations.<br>-&nbsp;**source**: attributes of the **distributedObject** set.<br>-&nbsp;**DistributedObject**: returns the distributed object created. | 
 
 ### Generating a Session ID
 
 Call **genSessionId()** to generate a session ID randomly. The generated session ID can be used to set the session ID of a distributed data object.
 
 **Table 2** API for generating a session ID randomly
-| Package| API| Description|
-| -------- | -------- | -------- |
-| ohos.data.distributedDataObject| genSessionId(): string | Generates a session ID, which can be used as the session ID of a distributed data object.|
+ | Package | API | Description |
+ | -------- | -------- | -------- |
+ | ohos.data.distributedDataObject | genSessionId(): string | Generates a session ID, which can be used as the session ID of a distributed data object. |
 
 ### Setting a SessionID for Distributed Data Objects
 
 Call **setSessionId()** to set a session ID for a distributed data object. The session ID is a unique identifier for one collaboration across devices. The distributed data objects to be synchronized must be associated with the same session ID.
 
 **Table 3** API for setting a session ID
-| Class| API| Description|
-| -------- | -------- | -------- |
-| DistributedDataObject | setSessionId(sessionId?: string): boolean | Sets a session ID for distributed data objects.<br>&nbsp;**sessionId**: session ID of a distributed object in a trusted network. To remove a distributed data object from the network, set this parameter to "" or leave it empty.|
+ | Class | API | Description |
+ | -------- | -------- | -------- |
+ | DistributedDataObject | setSessionId(sessionId?: string): boolean | Sets a session ID for distributed data objects.<br>**sessionId**: session ID of a distributed object in a trusted network. To remove a distributed data object from the network, set this parameter to "" or leave it empty. |
 
 ### Observing Data Changes
 
 Call **on()** to subscribe to data changes of a distributed data object. When the data changes, a callback will be invoked to return the data changes. You can use **off()** to unsubscribe from the data changes.
 
 **Table 4** APIs for observing data changes of a distributed data object
-| Class| API| Description| 
-| -------- | -------- | -------- |
-| DistributedDataObject| on(type: 'change', callback: Callback<{ sessionId: string, fields: Array&lt;string&gt; }>): void | Subscribes to data changes.| 
-| DistributedDataObject| off(type: 'change', callback?: Callback<{ sessionId: string, fields: Array&lt;string&gt; }>): void | Unsubscribes from data changes. <br>**Callback**: specifies callback used to return changes of the distributed data object. If this parameter is not specified, all callbacks related to data changes will be unregistered.|
+ | Class | API | Description | 
+ | -------- | -------- | -------- |
+ | DistributedDataObject | on(type: 'change', callback: Callback<{ sessionId: string, fields: Array&lt;string&gt; }>): void | Subscribes to data changes. | 
+ | DistributedDataObject | off(type: 'change', callback?: Callback<{ sessionId: string, fields: Array&lt;string&gt; }>): void | Unsubscribes from data changes. <br>**Callback**: specifies callback used to return changes of the distributed data object. If this parameter is not specified, all callbacks related to data changes will be unregistered. |
 
 ### Observing Online or Offline Status
 
 Call **on()** to subscribe to status changes of a distributed data object. The status can be online or offline. When the status changes, a callback will be invoked to return the status. You can use **off()** to unsubscribe from the status changes.
 
 **Table 5** APIs for observing status changes of a distributed data object
-| Class| API| Description|
-| -------- | -------- | -------- |
-| DistributedDataObject| on(type: 'status', callback: Callback<{ sessionId: string, networkId: string, status: 'online' \| 'offline' }>): void | Subscribes to the status changes of a distributed data object.|
-| DistributedDataObject| off(type: 'status', callback?: Callback<{ sessionId: string, deviceId: string, status: 'online' \| 'offline' }>): void | Unsubscribes from status changes of a distributed data object.|
+ | Class | API | Description |
+ | -------- | -------- | -------- |
+ | DistributedDataObject | on(type: 'status', callback: Callback<{ sessionId: string, networkId: string, status: 'online' \ | 'offline' }>): void | Subscribes to the status changes of a distributed data object. |
+ | DistributedDataObject | off(type: 'status', callback?: Callback<{ sessionId: string, deviceId: string, status: 'online' \ | 'offline' }>): void | Unsubscribes from status changes of a distributed data object. |
 
 
 
@@ -62,13 +62,13 @@ Call **on()** to subscribe to status changes of a distributed data object. The s
 The following example shows how to implement a distributed data object synchronization.
 
 1. Import the @ohos.data.distributedDataObject module to the development environment.
+
    ```js
    import distributedObject from '@ohos.data.distributedDataObject'
    ```
 
 2. Obtain a distributed data object instance.
 
-   The sample code is as follows:
    ```js
    var local_object = distributedObject.createDistributedObject({name:undefined, age:undefined, isVis:true, 
                   parent:undefined, list:undefined});
@@ -77,8 +77,6 @@ The following example shows how to implement a distributed data object synchroni
 
 
 3. Add the synchronization network. The data objects in the synchronization network include the local and remote objects.
-   
-   The sample code is as follows:
 
    ```js
    // Local object
@@ -94,9 +92,7 @@ The following example shows how to implement a distributed data object synchroni
    ```
    
 4. Observe the data changes of the distributed data object. You can subscribe to data changes of the remote object. When the data in the remote object changes, a callback will be called to return the data changes.
-
-   The sample code is as follows:
-   
+ 
    ```js
    function changeCallback(sessionId, changeData) {
         console.info("change" + sessionId);
@@ -113,8 +109,7 @@ The following example shows how to implement a distributed data object synchroni
    ```
    
 5. Modify object attributes. The object attributes support basic data types (such as number, Boolean, and string) and complex data types (array and nested basic types).
-   
-   The sample code is as follows:
+
    ```js
    local_object.name = "jack";
    local_object.age = 19;
@@ -133,22 +128,22 @@ The following example shows how to implement a distributed data object synchroni
    ```
 
 6. Access the distributed data object. Obtain the distributed data object attribute, which is the latest data on the network.
-   
-   The sample code is as follows:
+
    ```js
    console.info("name " + local_object["name"]); 
    ```
+
 7. Unsubscribe from data changes. You can specify the callback to unsubscribe from. If you do not specify the callback, all data change callbacks of the distributed data object will be unsubscribed from.
 
-   The sample code is as follows:
    ```js
    // Unsubscribe from the specified data change callback.
    local_object.off("change", changeCallback);
    // Unsubscribe from all data change callbacks. 
    local_object.off("change"); 
    ```
+
 8. Subscribe to the status (online/offline) changes of the distributed data object. A callback will be invoked to report the status change when the target distributed data object goes online or offline.
-   The sample code is as follows:
+
    ```js
     function statusCallback(sessionId, networkId, status) {
       this.response += "status changed " + sessionId + " " + status + " " + networkId;
@@ -156,21 +151,22 @@ The following example shows how to implement a distributed data object synchroni
    
     local_object.on("status", this.statusCallback);
    ```
+
 9. Unsubscribe from the status changes of the distributed data object. You can specify the callback to unsubscribe from. If you do not specify the callback, this API unsubscribes from all callbacks of this distributed data object.
-   
-    The sample code is as follows:
+
    ```js
    // Unsubscribe from the specified status change callback.
    local_object.off("status", statusCallback);
    // Unsubscribe from all status change callbacks.
    local_object.off("status");
    ```
+
 10. Remove a distributed data object from the synchronization network. Data changes on the local object will not be synchronized to the removed distributed data object.
 
-     The sample code is as follows:
-       ```js
-       local_object.setSessionId("");
-       ```
+    ```js
+    local_object.setSessionId("");
+    ```
+
 ## Samples
 
 The following example is provided for you to better understand the development of distributed data objects: