A Data ability helps applications manage access to data stored by themselves and other applications. It also provides APIs for sharing data with other applications either on the same device or across devices.
A Data ability helps applications manage access to data stored by themselves and other applications. It also provides APIs for sharing data with other applications either on the same device or across devices.
Data ability providers can customize data access-related APIs such as data inserting, deleting, updating, and querying, as well as file opening, and share data with other applications through these open APIs.
Data ability providers can customize data access-related APIs such as data inserting, deleting, updating, and querying, as well as file opening, and share data with other applications through these open APIs.
## Creating a Data Ability
## Available APIs
### 1. Implementation of the Data Subsystem
1. To meet the basic requirements of the database storage service, implement the **Insert**, **Query**, **Update**, and **Delete** APIs in the **Data** class to provide batch data processing. The traversal logic has been implemented by the **BatchInsert** and **ExecuteBatch** APIs.
**Table 1** Data ability lifecycle callbacks
2. The APIs used in the lifecycle of the Data ability are as follows:
|API|Description|
|:------|:------|
- onInitialized
|onInitialized|Called during ability initialization to initialize the relational database (RDB).|
|update|Updates data in the database.|
Called during ability initialization to initialize the relational database (RDB).
|query|Queries data in the database.|
|delete|Deletes one or multiple data records from the database.|
- update
|normalizeUri|Normalizes the URI. A normalized URI applies to cross-device use, persistence, backup, and restore. When the context changes, it ensures that the same data item can be referenced.|
|batchInsert|Inserts multiple data records into the database.|
Updates data in the database.
|denormalizeUri|Converts a normalized URI generated by **normalizeUri** into a denormalized URI.|
|insert|Inserts a data record into the database.|
- query
|openFile|Opens a file.|
|getFileTypes|Obtains the MIME type of a file.|
Queries data in the database.
|getType|Obtains the MIME type matching the data specified by the URI.|
|executeBatch|Operates data in the database in batches.|
- delete
|call|A customized API.|
Deletes one or multiple data records from the database.
## How to Develop
- normalizeUri
### Creating a Data Ability
Normalizes the URI. A normalized URI applies to cross-device use, persistence, backup, and restore. When the context changes, it ensures that the same data item can be referenced.
- batchInsert
Inserts multiple data records into the database.
- denormalizeUri
Converts a normalized URI generated by **normalizeUri** into a denormalized URI.
- insert
Inserts a data record into the database.
- openFile
Opens a file.
- getFileTypes
Obtains the MIME type of a file.
- getType
Obtains the MIME type matching the data specified by the URI.
- executeBatch
Operates data in the database in batches.
- call
A customized API.
1. To meet the basic requirements of the database storage service, implement the **Insert**, **Query**, **Update**, and **Delete** APIs in the **Data** class to provide batch data processing. The traversal logic has been implemented by the **BatchInsert** and **ExecuteBatch** APIs.
The following code snippet shows how to create a Data ability:
The following code snippet shows how to create a Data ability:
constSQL_CREATE_TABLE='CREATE TABLE IF NOT EXISTS book(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, age INTEGER, introduction TEXT NOT NULL)'
| "name" | Ability name, corresponding to the **Data** class name derived from **Ability**. |
| "type" | Ability type, which is **Data** for a Data ability. |
| "uri" | URI used for communication. |
| "visible" | Whether the Data ability is visible to other applications. When this parameter is set to **true**, the Data ability can communicate with other applications.|
| "name" | Ability name, corresponding to the **Data** class name derived from **Ability**. |
| "type" | Ability type, which is **Data** for a Data ability. |
| "uri" | URI used for communication. |
| "visible" | Whether the Data ability is visible to other applications. When this parameter is set to **true**, the Data ability can communicate with other applications.|
**config.json configuration example**
```json
"abilities":[{
```json
"abilities":[{
"srcPath":"DataAbility",
"srcPath":"DataAbility",
"name":".DataAbility",
"name":".DataAbility",
"icon":"$media:icon",
"icon":"$media:icon",
...
@@ -141,121 +97,142 @@ Data ability providers can customize data access-related APIs such as data inser
...
@@ -141,121 +97,142 @@ Data ability providers can customize data access-related APIs such as data inser
Import the basic dependency packages and obtain the URI string for communicating with the Data submodule.
The basic dependency packages include:
- @ohos.ability.featureAbility
- @ohos.data.dataability
- @ohos.data.rdb
#### Data Ability API Development
## Accessing a Data ability
### 1. Preparing for JS Application Development
Basic dependency packages:
1. @ohos.ability.featureAbility
2. @ohos.data.dataability
3. @ohos.data.rdb
URI string used for communication with the Data ability.
### 2. JS Application Development APIs
1. Create a Data ability helper.
Create a utility API object.
```js
For details about the APIs provided by **DataAbilityHelper**, see [DataAbilityHelper Module](../reference/apis/js-apis-dataAbilityHelper.md).
// Different from the URI defined in the config.json file, the URI passed in the parameter has an extra slash (/), because there is a DeviceID parameter between the second and the third slash (/).
```js
varurivar="dataability:///com.ix.DataAbility"
// Different from the URI defined in the config.json file, the URI passed in the parameter has an extra slash (/), because there is a DeviceID parameter between the second and the third slash (/).