The **DataShare** module allows an application to manage its own data and share data with other applications. Currently, data can be shared only between the applications on the same device.
The **DataShare** module allows an application to manage its own data and share data with other applications. Currently, data can be shared only between applications on the same device.
## Available APIs
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@@ -29,10 +29,10 @@ For more details, see [DataShareHelper](../reference/apis/js-apis-data-dataShare
## When to Use
**DataShare** can be divided into the following:
There are two roles in **DataShare**.
- Data provider: Implement functions of adding, deleting, modifying, and querying data, and opening files, and share data.
- Data consumer: Access the data provided by the provider using **DataShareHelper**.
- Data provider: adds, deletes, modifies, and queries data, opens files, and shares data.
- Data consumer: accesses the data provided by the provider using **DataShareHelper**.
2. Override **DataShareExtensionAbility** APIs based on actual requirements. For example, if the data provider provides only data query, override only the query() API.
2. Override **DataShareExtensionAbility** APIs based on actual requirements. For example, if the data provider provides only data query, override only the **query()** API.
3. Implement the data provider services. For example, implement data storage of the data provider by using a database, reading and writing files, or accessing the network.
The **DataShare** module allows an application to manage its own data and share data with other applications. Currently, data can be shared only between the applications on the same device.
The **DataShare** module allows an application to manage its own data and share data with other applications. Currently, data can be shared only between applications on the same device.
**DataShare** is used in application scenarios, such as contacts, short message service (SMS), and media gallery. However, not all data, such as accounts and passwords, can be accessed by other applications. Some data, such as SMS messages, can only be queried by other applications. **DataShare** provides a secure data sharing mechanism for applications.
Data needs to be shared in a wealth of scenarios. For example, contacts, short message service (SMS), and media gallery always needs to be shared. However, certain data, such as accounts and passwords, cannot be shared. Some data, such as SMS messages, can be queried but not modified by other applications. **DataShare** provides a secure data sharing mechanism for applications in a variety of scenarios.
The data provider can directly use the **DataShare** framework to share data with other applications without complex encapsulation. The data consumer only needs to learn and use a set of interfaces because the data access mode does not vary with the data provisioning mode. This greatly reduces the learning time and development difficulty.
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@@ -45,7 +45,7 @@ Before you get started, familiarize yourself with the following concepts:
- The **DataShareHelper** module, as the data consumer, provides interfaces for accessing data, including adding, deleting, modifying, and querying data.
- The data consumer communicates with the data provider using inter-process communication (IPC). The data provider can be implemented through a database or other data storage.
- The **ResultSet** module is implemented through shared memory. Share memory stores the result sets, and interfaces are provided to traverse result sets.
- The **ResultSet** module is implemented through shared memory. Shared memory stores the result sets, and interfaces are provided to traverse result sets.
@@ -4,11 +4,11 @@ The **DataShareExtensionAbility** module provides Extension abilities for data s
>**NOTE**
>
>The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>
>The APIs provided by this module are system APIs.
>The APIs provided by this module are system APIs.
>
>The APIs of this module can be used only in the stage model.
>The APIs of this module can be used only in the stage model.
Obtains the Multipurpose Internet Mail Extensions (MIME) types supported by a file. This API is called by the server and can be overridden as required.
The **ValueBucket** module holds data in key-value (KV) pairs. You can use it to insert data into a database.
>**NOTE**
>**NOTE**
>
>The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>
> The APIs provided by this module are system APIs.
The **DataShare** module allows an application to manage its own data and share data with other applications on the same device.
>**NOTE**
>**NOTE**
>
>The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>
> The APIs provided by this module are system APIs.
>
> The APIs of this module can be used only in the stage model.
Provides a **DataShareHelper** instance to access or manage data on the server. Before calling an API provided by **DataShareHelper**, you must create a **DataShareHelper** instance using [createDataShareHelper](#datasharecreatedatasharehelper).
| mode | string | Yes | File open mode.<br>**r** means to open a file for reading; **w** means to open a file for writing (erasing any data in the file); **wa** means to open a file in append mode for writing at the end of the file; **rw** means to open a file for both reading and writing.|
| callback | AsyncCallback<number> | Yes | Callback invoked to return the result. If the operation is successful, **err** is **undefined** and **data** is the file descriptor. Otherwise, **err** is an error object.|
| mode | string | Yes | File open mode.<br>**r** means to open a file for reading; **w** means to open a file for writing (erasing any data in the file); **wa** means to open a file in append mode for writing at the end of the file; **rw** means to open a file for both reading and writing.|
**Return value**
| Type | Description |
| --------------- | ---------------- |
| Promise<number> | Promise used to return the file descriptor.|
Subscribes to changes of the specified data. After an observer is registered, the subscriber will receive a notification when the change notification is triggered (the **notifyChange()** method is called). This API uses an asynchronous callback to return the result.
| type | string | Yes | Event type to subscribe to. The value is **dataChange**, which indicates data change events.|
| uri | string | Yes | URI of the data.|
| callback | AsyncCallback<void> | Yes | Called when the change notification is triggered. In this case, **err** is **undefined**. Otherwise, it is not called or**err** is an error object.|
| callback | AsyncCallback<void> | Yes | Callback invoked to return the result. If the data is changed, the value of **err** is **undefined**. Otherwise, this callback is not invoked or the value of**err** is an error object.|
| callback | AsyncCallback<string> | Yes | Callback invoked to return the result. If the operation is successful, **err** is **undefined** and **data** is the MIME type obtained. Otherwise, **err** is an error object.|
| mimeTypeFilter | string | Yes | MIME types to match. Example:<br>**\*/\***: Obtain all supported types.<br>**image/\***: Obtain the MIMEs with the main type of **image**.<br>**\*/jpg**: Obtain the MIMEs with the subtype of **jpg**.|
| callback | AsyncCallback<Array\<string>> | Yes | Callback invoked to return the result. If the operation is successful, **err** is **undefined** and **data** is the MIME types obtained. Otherwise, **err** is an error object.|
| mimeTypeFilter | string | Yes | MIME types to match. Example:<br>**\*/\***: Obtain all supported types.<br>**image/\***: Obtain the MIMEs with the main type of **image**.<br>**\*/jpg**: Obtain the MIMEs with the subtype of **jpg**.|
Normalizes a **DataShare** URI. The **DataShare** URI can be used only by the local device, but the normalized URI can be used across devices. This API uses an asynchronous callback to return the result.
Normalizes a **DataShare** URI. The **DataShare** URI can be used only by the local device, but the normalized URI can be used across devices. This API uses a promise to return the result.
