@@ -13,7 +13,7 @@ The **DataShare** module allows an application to manage its own data and share
|query?(uri: string, predicates: DataSharePredicates, columns: Array<string>, callback: AsyncCallback<Object>): void|Queries data from the database.|
|delete?(uri: string, predicates: DataSharePredicates, callback: AsyncCallback<number>): void|Deletes data from the database.|
For more information, see [DataShareExtensionAbility](../reference/apis/js-apis-application-dataShareExtensionAbility.md).
For details about the data provider APIs, see [DataShareExtensionAbility](../reference/apis/js-apis-application-dataShareExtensionAbility.md).
**Table 2** APIs of the data consumer
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@@ -29,7 +29,7 @@ For more information, see [DataShareHelper](../reference/apis/js-apis-data-dataS
## When to Use
There are two roles in **DataShare**:
There are two roles in **DataShare**:
- Data provider: adds, deletes, modifies, and queries data, opens files, and shares data.
- Data consumer: accesses the data provided by the provider using **DataShareHelper**.
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@@ -38,7 +38,47 @@ Examples are given below.
### Data Provider Application Development (Only for System Applications)
1. Import the dependencies.
[DataShareExtensionAbility](../reference/apis/js-apis-application-dataShareExtensionAbility.md) provides the following APIs. You can override the APIs as required.
-**onCreate**
Called by the server to initialize service logic when the **DataShare** client connects to the **DataShareExtensionAbility** server.
-**insert**
Inserts data. This API is called when the client requests to insert data.
-**update**
Updates data. This API is called when the client requests to update data.
-**delete**
Deletes data. This API is called when the client requests to delete data.
-**query**
Queries data. This API is called when the client requests to query data.
-**batchInsert**
Batch inserts data. This API is called when the client requests to batch insert data.
-**normalizeUri**
Converts the URI provided by the client to the URI used by the server. This API can be overridden as required.
-**denormalizeUri**
Converts the URI used by the server to the initial URI passed by the client. This API can be overridden as required.
Before implementing a **DataShare** service, create a **DataShareExtensionAbility** object in the DevEco Studio project as follows:
1. In the **ets** directory of the **Module** project, right-click and choose **New > Directory** to create a directory named **DataShareAbility**.
2. Right-click the **DataShareAbility** directory, and choose **New > TypeScript File** to create a file named **DataShareAbility.ts**.
3. In the **DataShareAbility.ts** file, import the **DataShareExtensionAbility** and other dependencies.
2. Override **DataShareExtensionAbility** APIs based on actual requirements. For example, if the data provider provides only data query, override only the **query()** API.
4. Override the **DataShareExtensionAbility** APIs based on actual requirements. For example, if the data provider provides only data query, override only **query()**.
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.
5. 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.
2. Define the URI string for communicating with the data provider.
```ts
// Different from the URI defined in the module.json5 file, the URI passed in the parameter has an extra slash (/), because there is a DeviceID parameter between the second and the third slash (/).
4. Use the APIs provided by **DataShareHelper** to access the services provided by the provider, for example, adding, deleting, modifying, and querying data.
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** must be used together with [DataShareExtensionAbility](../reference/apis/js-apis-application-dataShareExtensionAbility.md).
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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@@ -16,22 +18,22 @@ Before you get started, familiarize yourself with the following concepts:
- Data provider
An application that provides data and implements related services. It is also called a producer or server.
The **DataShareExtensionAbility** based on the stage model implements functions, such as selectively adding, deleting, modifying, and querying data, and opening files. It implements services related to cross-application data sharing.
- Data consumer
An application that accesses the data or services provided by a data provider. It is also called a client.
The data consumer uses **DataShareHelper**, a utility class created by [createDataShareHelper()](../reference/apis/js-apis-data-dataShare.md#datasharecreatedatasharehelper), to access the data provided by the data provider.
-**ValuesBucket**
One or more data records stored in the form of key-value (KV) pairs. The keys are of the string type. The values can be of the number, string, Boolean, or Unit8Array type.
- Result set
A collection of query results. Flexible data access modes are provided for users to obtain data.
- Predicate
Conditions specified for updating, deleting, or querying data in the database.
## Working Principles
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@@ -41,7 +43,7 @@ Before you get started, familiarize yourself with the following concepts:
- The **DataShareExtAbility** module, as the data provider, implements data sharing between applications.
- The **DataShareExtAbility** module, as the data provider, implements services related to data sharing between applications.
- 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.
