update docs

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>

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

 # Preferences Development
 
+> **NOTE**
+>
+> This feature is supported since API Version 9. For the versions earlier than API Version 9, use [Lightweight Storage](../reference/apis/js-apis-data-storage.md) APIs.
+
 ## When to Use
 
 Preferences are ideal for storing data frequently used by applications, but not for storing a large amount of data or data with frequent changes. The application data is persistently stored on a device in the form of files. Note that the instance accessed by an application contains all data of the file. The data is always loaded to the memory of the device until the application removes it from the memory. The application can perform data operations using the **Preferences** APIs.
 
 ## Available APIs
 
-Preferences provide capabilities for processing data in the form of key-value (KV) pairs and support data persistence, modification, and query. In KV pairs, keys are of the string type, and values can be of the number, string, or Boolean type.
+Preferences provide capabilities for processing data in the form of key-value (KV) pairs and support data persistence, modification, and query. In KV pairs, keys are of the string type, and values can be of the number, string, or Boolean type. For more APIs related to preferences, see [Preferences](../reference/apis/js-apis-data-preferences.md).
 
 ### Creating a Preferences Instance
 
@@ -26,7 +30,7 @@ Call the **put()** method to add or modify data in a **Preferences** instance.
 
 | Class   | API                                            | Description                                           |
 | ------- | -------------------------------------------------- | ----------------------------------------------- |
-| Preferences | put(key: string, value: ValueType): Promise\<void> | Writes data of the number, string, and Boolean types.|
+| Preferences | put(key: string, value: ValueType): Promise\<void> | Writes data with the value type of number, string, boolean, Array\<number>, Array\<string>, or Array\<boolean>.|
 
 ### Reading Data
 
@@ -36,7 +40,7 @@ Call the **get()** method to read data from a **Preferences** instance.
 
 | Class   | API                                                    | Description                                           |
 | ------- | ---------------------------------------------------------- | ----------------------------------------------- |
-| Preferences | get(key: string, defValue: ValueType): Promise\<ValueType> | Reads data of the number, string, and Boolean types.|
+| Preferences | get(key: string, defValue: ValueType): Promise\<ValueType> | Obtains data with the value type of number, string, boolean, Array\<number>, Array\<string>, or Array\<boolean>.|
 
 ### Storing Data Persistently
 
@@ -67,7 +71,7 @@ Use the following APIs to delete a **Preferences** instance or data file.
 
 | Package             | API                                              | Description                                                        |
 | ----------------- | ---------------------------------------------------- | ------------------------------------------------------------ |
-| ohos.data.preferences | deletePreferences(context: Context, name: string): Promise<void>;     | Deletes a **Preferences** instance from the cache and deletes its file from the device.|
+| ohos.data.preferences | deletePreferences(context: Context, name: string): Promise\<void>;     | Deletes a **Preferences** instance from the cache and deletes its file from the device.|
 | ohos.data.preferences | removePreferencesFromCache(context: Context, name: string): Promise\<void>; | Removes a **Preferences** instance from the memory to release memory.
 
 ## How to Develop
@@ -91,8 +95,8 @@ Use the following APIs to delete a **Preferences** instance or data file.
 
    ```js
    promise.then((preferences) => {
-       let getPromise = preferences.put('startup', 'auto')
-       getPromise.then(() => {
+       let putPromise = preferences.put('startup', 'auto')
+       putPromise.then(() => {
            console.info("Put the value of startup successfully.")
        }).catch((err) => {
            console.info("Failed to put the value of startup with err: " + err)

en/application-dev/reference/apis/js-apis-data-storage.md

@@ -13,7 +13,7 @@ Lightweight storage provides applications with data processing capability and al
 ## Modules to Import
 
 ```js
-import dataStorage from '@ohos.data.storage';
+import data_storage from '@ohos.data.storage';
 ```
 
 ## Constants
@@ -26,7 +26,7 @@ import dataStorage from '@ohos.data.storage';
 | MAX_VALUE_LENGTH | string | Yes| No| Maximum length of a value. It must be less than 8192 bytes.|
 
 
-## dataStorage.getStorageSync
+## data_storage.getStorageSync
 
 getStorageSync(path: string): Storage
 
@@ -46,24 +46,17 @@ Reads the specified file and loads its data to the **Storage** instance for data
 
 **Example**
   ```js
-  import dataStorage from '@ohos.data.storage'
-  import featureAbility from '@ohos.ability.featureAbility'
+  import data_storage from '@ohos.data.storage'
+  
+  let path = '/data/storage/el2/database'
+  let storage = data_storage.getStorageSync(path + '/mystore')
+  storage.putSync('startup', 'auto')
+  storage.flushSync()
   
-  var context = featureAbility.getContext()
-  context.getFilesDir((err, path) => {
-      if (err) {
-          console.error('getFilesDir failed. err: ' + JSON.stringify(err));
-          return;
-      }
-      console.info('getFilesDir successful. path:' + JSON.stringify(path));
-      let storage = dataStorage.getStorageSync(path + '/mystore')
-      storage.putSync('startup', 'auto')
-      storage.flushSync()
-  });
   ```
 
 
-## dataStorage.getStorage
+## data_storage.getStorage
 
 getStorage(path: string, callback: AsyncCallback<Storage>): void
 
@@ -79,29 +72,21 @@ Reads the specified file and loads its data to the **Storage** instance for data
 
 **Example**
   ```js
-  import dataStorage from '@ohos.data.storage'
-  import featureAbility from '@ohos.ability.featureAbility'
+  import data_storage from '@ohos.data.storage'
   
-  var context = featureAbility.getContext()
-  context.getFilesDir((err, path) => {
+  let path = '/data/storage/el2/database'
+  data_storage.getStorage(path + '/mystore', function (err, storage) {
       if (err) {
-          console.error('getFilesDir failed. err: ' + JSON.stringify(err));
+          console.info("Failed to get the storage. Path: " + path + '/mystore')
           return;
       }
-      console.info('getFilesDir successful. path:' + JSON.stringify(path));
-      dataStorage.getStorage(path + '/mystore', function (err, storage) {
-          if (err) {
-              console.info("Get the storage failed, path: " + path + '/mystore')
-              return;
-          }
-          storage.putSync('startup', 'auto')
-          storage.flushSync()
-      })
-  });
+      storage.putSync('startup', 'auto')
+      storage.flushSync()
+  })
   ```
 
 
-## dataStorage.getStorage
+## data_storage.getStorage
 
 getStorage(path: string): Promise<Storage>
 
@@ -121,28 +106,21 @@ Reads the specified file and loads its data to the **Storage** instance for data
 
 **Example**
   ```js
-  import dataStorage from '@ohos.data.storage'
-  import featureAbility from '@ohos.ability.featureAbility'
+  import data_storage from '@ohos.data.storage'
   
-  var context = featureAbility.getContext()
-  context.getFilesDir((err, path) => {
-      if (err) {
-          console.info("Get the storage failed, path: " + path + '/mystore')
-          return;
-      }
-      console.info('getFilesDir successful. path:' + JSON.stringify(path));
-      let promisegetSt = dataStorage.getStorage(path + '/mystore')
-      promisegetSt.then((storage) => {
-          storage.putSync('startup', 'auto')
-          storage.flushSync()
-      }).catch((err) => {
-          console.info("Get the storage failed, path: " + path + '/mystore')
-      })
-  });
+  let path = '/data/storage/el2/database'
+  
+  let getPromise = data_storage.getStorage(path + '/mystore')
+  getPromise.then((storage) => {
+      storage.putSync('startup', 'auto')
+      storage.flushSync()
+  }).catch((err) => {
+      console.info("Failed to get the storage. Path: " + path + '/mystore')
+  })
   ```
 
 
-## dataStorage.deleteStorageSync
+## data_storage.deleteStorageSync
 
 deleteStorageSync(path: string): void
 
@@ -157,11 +135,12 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
 
 **Example**
   ```js
-  dataStorage.deleteStorageSync(path + '/mystore')
+  let path = '/data/storage/el2/database'
+  data_storage.deleteStorageSync(path + '/mystore')
   ```
 
 
-## dataStorage.deleteStorage
+## data_storage.deleteStorage
 
 deleteStorage(path: string, callback: AsyncCallback<void>): void
 
@@ -173,11 +152,12 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
   | Name| Type| Mandatory| Description|
   | -------- | -------- | -------- | -------- |
   | path | string | Yes| Path of the target file.|
-  | callback | AsyncCallback<void> | Yes| Callback used to return the execution result.|
+  | callback | AsyncCallback<void> | Yes| Callback that returns no value.|
 
 **Example**
   ```js
-  dataStorage.deleteStorage(path + '/mystore', function (err) {
+  let path = '/data/storage/el2/database'
+  data_storage.deleteStorage(path + '/mystore', function (err) {
       if (err) {
           console.info("Deleted failed with err: " + err)
           return
@@ -187,7 +167,7 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
   ```
 
 
-## dataStorage.deleteStorage
+## data_storage.deleteStorage
 
 deleteStorage(path: string): Promise<void>
 
@@ -203,11 +183,12 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
 **Return value**
   | Type| Description|
   | -------- | -------- |
-  | Promise<void> | Promise used to return the result.|
+  | Promise<void> | Promise that returns no value.|
 
 **Example**
   ```js
-  let promisedelSt = dataStorage.deleteStorage(path + '/mystore')
+  let path = '/data/storage/el2/database'
+  let promisedelSt = data_storage.deleteStorage(path + '/mystore')
   promisedelSt.then(() => {
       console.info("Deleted successfully.")
   }).catch((err) => {
@@ -216,7 +197,7 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
   ```
 
 
-## dataStorage.removeStorageFromCacheSync
+## data_storage.removeStorageFromCacheSync
 
 removeStorageFromCacheSync(path: string): void
 
@@ -231,11 +212,12 @@ Removes the singleton **Storage** instance of a file from the cache. The removed
 
 **Example**
   ```js
-  dataStorage.removeStorageFromCacheSync(path + '/mystore')
+  let path = '/data/storage/el2/database'
+  data_storage.removeStorageFromCacheSync(path + '/mystore')
   ```
 
 
-## dataStorage.removeStorageFromCache
+## data_storage.removeStorageFromCache
 
 removeStorageFromCache(path: string, callback: AsyncCallback<void>): void
 
@@ -247,11 +229,12 @@ Removes the singleton **Storage** instance of a file from the cache. The removed
   | Name| Type| Mandatory| Description|
   | -------- | -------- | -------- | -------- |
   | path | string | Yes| Path of the target file.|
-  | callback | AsyncCallback<void> | Yes| Callback used to return the execution result.|
+  | callback | AsyncCallback<void> | Yes| Callback that returns no value.|
 
 **Example**
   ```js
-  dataStorage.removeStorageFromCache(path + '/mystore', function (err) {
+  let path = '/data/storage/el2/database'
+  data_storage.removeStorageFromCache(path + '/mystore', function (err) {
       if (err) {
           console.info("Removed storage from cache failed with err: " + err)
           return
@@ -261,7 +244,7 @@ Removes the singleton **Storage** instance of a file from the cache. The removed
   ```
 
 
-## dataStorage.removeStorageFromCache
+## data_storage.removeStorageFromCache
 
 removeStorageFromCache(path: string): Promise<void>
 
@@ -277,11 +260,12 @@ Removes the singleton **Storage** instance of a file from the cache. The removed
 **Return value**
   | Type| Description|
   | -------- | -------- |
-  | Promise<void> | Promise used to return the result.|
+  | Promise<void> | Promise that returns no value.|
 
 **Example**
   ```js
-  let promiserevSt = dataStorage.removeStorageFromCache(path + '/mystore')
+  let path = '/data/storage/el2/database'
+  let promiserevSt = data_storage.removeStorageFromCache(path + '/mystore')
   promiserevSt.then(() => {
       console.info("Removed storage from cache successfully.")
   }).catch((err) => {
@@ -412,7 +396,7 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat
   | -------- | -------- | -------- | -------- |
   | key | string | Yes| Key of the data. It cannot be empty.|
   | value | [ValueType](#valuetype) | Yes| New value to store. It can be a number, string, or Boolean value.|
-  | callback | AsyncCallback<void> | Yes| Callback used to return the execution result.|
+  | callback | AsyncCallback<void> | Yes| Callback that returns no value.|
 
 **Example**
   ```js
@@ -443,7 +427,7 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat
 **Return value**
   | Type| Description|
   | -------- | -------- |
-  | Promise<void> | Promise used to return the result.|
+  | Promise<void> | Promise that returns no value.|
 
 **Example**
   ```js
@@ -578,7 +562,7 @@ Deletes data with the specified key from this storage object. This API uses an a
   | Name| Type| Mandatory| Description|
   | -------- | -------- | -------- | -------- |
   | key | string | Yes| Key of the data. It cannot be empty.|
-  | callback | AsyncCallback<void> | Yes| Callback used to return the execution result.|
+  | callback | AsyncCallback<void> | Yes| Callback that returns no value.|
 
 **Example**
   ```js
@@ -608,7 +592,7 @@ Deletes data with the specified key from this storage object. This API uses a pr
 **Return value**
   | Type| Description|
   | -------- | -------- |
-  | Promise<void> | Promise used to return the result.|
+  | Promise<void> | Promise that returns no value.|
 
 **Example**
   ```js
@@ -646,7 +630,7 @@ Saves the modification of this object to the **Storage** instance and synchroniz
 **Parameters**
   | Name| Type| Mandatory| Description|
   | -------- | -------- | -------- | -------- |
-  | callback | AsyncCallback<void> | Yes| Callback used to return the execution result.|
+  | callback | AsyncCallback<void> | Yes| Callback that returns no value.|
 
 **Example**
   ```js
@@ -671,7 +655,7 @@ Saves the modification of this object to the **Storage** instance and synchroniz
 **Return value**
   | Type| Description|
   | -------- | -------- |
-  | Promise<void> | Promise used to return the result.|
+  | Promise<void> | Promise that returns no value.|
 
 **Example**
   ```js
@@ -709,7 +693,7 @@ Clears this **Storage** object. This API uses an asynchronous callback to return
 **Parameters**
   | Name| Type| Mandatory| Description|
   | -------- | -------- | -------- | -------- |
-  | callback | AsyncCallback<void> | Yes| Callback used to return the execution result.|
+  | callback | AsyncCallback<void> | Yes| Callback that returns no value.|
 
 **Example**
   ```js
@@ -734,7 +718,7 @@ Clears this **Storage** object. This API uses a promise to return the result.
 **Return value**
   | Type| Description|
   | -------- | -------- |
-  | Promise<void> | Promise used to return the result.|
+  | Promise<void> | Promise that returns no value.|
 
 **Example**
   ```js