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提交 12fd8e71 编写于 作者: A Annie_wang
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update docs 

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>
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en/application-dev/reference/apis/js-apis-data-storage.md
浏览文件 @ 12fd8e71
......@@ -3,9 +3,11 @@
Lightweight storage provides applications with data processing capability and allows applications to perform lightweight data storage and query. Data is stored in key-value (KV) pairs. Keys are of the string type, and values can be of the number, string, or Boolean type.
> **NOTE**<br/>
> **NOTE**
>
> The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>
>
## Modules to Import
......@@ -33,20 +35,20 @@ Reads the specified file and loads its data to the **Storage** instance for data
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
**Return value**
| Type| Description|
| -------- | -------- |
| [Storage](#storage) | **Storage** instance used for data storage operations.|
| Type| Description|
| -------- | -------- |
| [Storage](#storage) | **Storage** instance used for data storage operations.|
**Example**
```js
import data_storage from '@ohos.data.storage'
var path = '/data/storage/el2/database/test_storage'
let path = '/data/storage/el2/database'
let storage = data_storage.getStorageSync(path + '/mystore')
storage.putSync('startup', 'auto')
storage.flushSync()
......@@ -63,19 +65,19 @@ Reads the specified file and loads its data to the **Storage** instance for data
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| callback | AsyncCallback&lt;[Storage](#storage)&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| callback | AsyncCallback&lt;[Storage](#storage)&gt; | Yes| Callback used to return the execution result.|
**Example**
```js
import data_storage from '@ohos.data.storage'
var path = '/data/storage/el2/database/test_storage'
let path = '/data/storage/el2/database'
data_storage.getStorage(path + '/mystore', function (err, storage) {
if (err) {
console.info("Get the storage failed, path: " + path + '/mystore')
console.info("Failed to get the storage. Path: " + path + '/mystore')
return;
}
storage.putSync('startup', 'auto')
......@@ -93,27 +95,27 @@ Reads the specified file and loads its data to the **Storage** instance for data
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;[Storage](#storage)&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;[Storage](#storage)&gt; | Promise used to return the result.|
**Example**
```js
import data_storage from '@ohos.data.storage'
var path = '/data/storage/el2/database/test_storage'
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("Get the storage failed, path: " + path + '/mystore')
console.info("Failed to get the storage. Path: " + path + '/mystore')
})
```
......@@ -127,12 +129,13 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
**Example**
```js
let path = '/data/storage/el2/database'
data_storage.deleteStorageSync(path + '/mystore')
```
......@@ -146,13 +149,14 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback that returns no value.|
**Example**
```js
let path = '/data/storage/el2/database'
data_storage.deleteStorage(path + '/mystore', function (err) {
if (err) {
console.info("Deleted failed with err: " + err)
......@@ -172,17 +176,18 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let path = '/data/storage/el2/database'
let promisedelSt = data_storage.deleteStorage(path + '/mystore')
promisedelSt.then(() => {
console.info("Deleted successfully.")
......@@ -201,12 +206,13 @@ Removes the singleton **Storage** instance of a file from the cache. The removed
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
**Example**
```js
let path = '/data/storage/el2/database'
data_storage.removeStorageFromCacheSync(path + '/mystore')
```
......@@ -220,13 +226,14 @@ Removes the singleton **Storage** instance of a file from the cache. The removed
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback that returns no value.|
**Example**
```js
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)
......@@ -246,17 +253,18 @@ Removes the singleton **Storage** instance of a file from the cache. The removed
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| path | string | Yes| Path of the target file.|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let path = '/data/storage/el2/database'
let promiserevSt = data_storage.removeStorageFromCache(path + '/mystore')
promiserevSt.then(() => {
console.info("Removed storage from cache successfully.")
......@@ -280,15 +288,15 @@ Obtains the value corresponding to a key. If the value is null or not in the def
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| defValue | [ValueType](#valuetype) | Yes| Default value to be returned if the value of the specified key does not exist. It can be a number, string, or Boolean value.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| defValue | [ValueType](#valuetype) | Yes| Default value to be returned if the value of the specified key does not exist. It can be a number, string, or Boolean value.|
**Return value**
| Type| Description|
| -------- | -------- |
| ValueType | Value corresponding to the specified key. If the value is null or not in the default value format, the default value is returned.|
| Type| Description|
| -------- | -------- |
| ValueType | Value corresponding to the specified key. If the value is null or not in the default value format, the default value is returned.|
**Example**
```js
......@@ -306,11 +314,11 @@ Obtains the value corresponding to a key. If the value is null or not in the def
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| defValue | [ValueType](#valuetype) | Yes| Default value to be returned. It can be a number, string, or Boolean value.|
| callback | AsyncCallback&lt;ValueType&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| defValue | [ValueType](#valuetype) | Yes| Default value to be returned. It can be a number, string, or Boolean value.|
| callback | AsyncCallback&lt;ValueType&gt; | Yes| Callback used to return the execution result.|
**Example**
```js
......@@ -340,9 +348,9 @@ Obtains the value corresponding to a key. If the value is null or not in the def
| defValue | [ValueType](#valuetype) | Yes| Default value to be returned. It can be a number, string, or Boolean value.|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;ValueType&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;ValueType&gt; | Promise used to return the result.|
**Example**
```js
......@@ -364,10 +372,10 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| 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.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| 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.|
**Example**
```js
......@@ -384,11 +392,11 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| 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&lt;void&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| 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&lt;void&gt; | Yes| Callback that returns no value.|
**Example**
```js
......@@ -411,15 +419,15 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| 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.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| 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.|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
......@@ -441,14 +449,14 @@ Checks whether the storage object contains data with a given key.
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
**Return value**
| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise.|
| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise.|
**Example**
```js
......@@ -468,15 +476,15 @@ Checks whether the storage object contains data with a given key. This API uses
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| callback | AsyncCallback&lt;boolean&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| callback | AsyncCallback&lt;boolean&gt; | Yes| Callback used to return the execution result.|
**Return value**
| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise.|
| Type| Description|
| -------- | -------- |
| boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise.|
**Example**
```js
......@@ -501,14 +509,14 @@ Checks whether the storage object contains data with a given key. This API uses
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;boolean&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;boolean&gt; | Promise used to return the result.|
**Example**
```js
......@@ -532,9 +540,9 @@ Deletes data with the specified key from this storage object.
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
**Example**
```js
......@@ -551,10 +559,10 @@ Deletes data with the specified key from this storage object. This API uses an a
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data. It cannot be empty.|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback that returns no value.|
**Example**
```js
......@@ -577,14 +585,14 @@ Deletes data with the specified key from this storage object. This API uses a pr
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| key | string | Yes| Key of the data.|
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
......@@ -620,9 +628,9 @@ Saves the modification of this object to the **Storage** instance and synchroniz
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;void&gt; | Yes| Callback that returns no value.|
**Example**
```js
......@@ -645,9 +653,9 @@ Saves the modification of this object to the **Storage** instance and synchroniz
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
......@@ -683,9 +691,9 @@ Clears this **Storage** object. This API uses an asynchronous callback to return
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the execution result.|
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;void&gt; | Yes| Callback that returns no value.|
**Example**
```js
......@@ -708,9 +716,9 @@ Clears this **Storage** object. This API uses a promise to return the result.
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
......@@ -732,10 +740,10 @@ Subscribes to data changes. The **StorageObserver** needs to be implemented. Whe
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Description|
| -------- | -------- | -------- |
| type | string | Event type. The value **change** indicates data change events.|
| callback | Callback&lt;[StorageObserver](#storageobserver)&gt; | Callback used to return data changes.|
| Name| Type| Description|
| -------- | -------- | -------- |
| type | string | Event type. The value **change** indicates data change events.|
| callback | Callback&lt;[StorageObserver](#storageobserver)&gt; | Callback used to return data changes.|
**Example**
```js
......@@ -757,10 +765,10 @@ Unsubscribes from data changes.
**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
**Parameters**
| Name| Type| Description|
| -------- | -------- | -------- |
| type | string | Event type. The value **change** indicates data change events.|
| callback | Callback&lt;[StorageObserver](#storageobserver)&gt; | Callback used to return data changes.|
| Name| Type| Description|
| -------- | -------- | -------- |
| type | string | Event type. The value **change** indicates data change events.|
| callback | Callback&lt;[StorageObserver](#storageobserver)&gt; | Callback used to return data changes.|
**Example**
```js
......
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