1# @system.storage (Data Storage)
2
3>  **NOTE**
4>
5>  - The APIs of this module are no longer maintained since API version 6, and you are advised to use [`@ohos.data.storage`](js-apis-data-storage.md). From API version 9, you are advised to use [`@ohos.data.preferences`](js-apis-data-preferences.md).
6>
7>  - The initial APIs of this module are supported since API version 3. Newly added APIs will be marked with a superscript to indicate their earliest API version.
8>
9>  - The APIs of this module can be used only in the FA model.
10
11## Modules to Import
12
13```js
14import storage from '@system.storage';
15```
16
17## storage.get
18
19get(options: GetStorageOptions): void
20
21Reads the value stored in the cache based on the specified key.
22
23**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
24
25**Parameters**
26
27| Name | Type                   | Mandatory| Description      |
28| ------- | -------------------- | ---- | ---------- |
29| options | [GetStorageOptions](#getstorageoptions) | Yes  | API configuration.|
30
31**Example**
32
33```js
34export default {
35  storageGet() {
36    storage.get({
37      key: 'storage_key',
38      success: function(data) {
39        console.log('call storage.get success: ' + data);
40      },
41      fail: function(data, code) {
42        console.log('call storage.get fail, code: ' + code + ', data: ' + data);
43      },
44      complete: function() {
45        console.log('call complete');
46      },
47    });
48  }
49}
50```
51
52## storage.set
53
54set(options: SetStorageOptions): void
55
56Sets the value in the cache based on the specified key.
57
58**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
59
60**Parameters**
61
62| Name | Type                  | Mandatory| Description      |
63| ------- | ------------------- | ---- | ---------- |
64| options | [SetStorageOptions](#setstorageoptions) | Yes  | API configuration.|
65
66**Example**
67
68```js
69export default {
70  storageSet() {
71    storage.set({
72      key: 'storage_key',
73      value: 'storage value',
74      success: function() {
75        console.log('call storage.set success.');
76      },
77      fail: function(data, code) {
78        console.log('call storage.set fail, code: ' + code + ', data: ' + data);
79      },
80    });
81  }
82}
83```
84
85## storage.clear
86
87clear(options?: ClearStorageOptions): void
88
89Clears the key-value pairs from the cache.
90
91**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
92
93**Parameters**
94
95| Name | Type                                       | Mandatory| Description          |
96| ------- | ------------------------------------------- | ---- | -------------- |
97| options | [ClearStorageOptions](#clearstorageoptions) | No  | API configuration.|
98
99**Example**
100
101```js
102export default {
103  storageClear() {
104    storage.clear({
105      success: function() {
106        console.log('call storage.clear success.');
107      },
108      fail: function(data, code) {
109        console.log('call storage.clear fail, code: ' + code + ', data: ' + data);
110      },
111    });
112  }
113}
114```
115
116## storage.delete
117
118delete(options: DeleteStorageOptions): void
119
120Deletes the key-value pair based on the specified key.
121
122**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
123
124**Parameters**
125
126| Name | Type                                         | Mandatory| Description          |
127| ------- | --------------------------------------------- | ---- | -------------- |
128| options | [DeleteStorageOptions](#deletestorageoptions) | Yes  | API configuration.|
129
130**Example**
131
132```js
133export default {
134  storageDelete() {
135    storage.delete({
136      key: 'Storage1',
137      success: function() {
138        console.log('call storage.delete success.');
139      },
140      fail: function(data, code) {
141        console.log('call storage.delete fail, code: ' + code + ', data: ' + data);
142      },
143    });
144  }
145}
146```
147
148## GetStorageOptions
149
150**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
151
152| Name    | Type         | Mandatory| Description                    |
153| -------- | ---------------- | ---- | ------------------- |
154| key      | string                               | Yes  | Key of the target data.                                     |
155| default  | string                               | No  | Default value returned when the specified key does not exist.                             |
156| success  | (data: any) => void                  | No  | Called to return the result when **storage.get()** is called successfully. **data** is the value indexed by the specified key. |
157| fail     | (data: string, code: number) => void | No  | Called to return the result when **storage.get()** fails to be called. **data** is the error information, and **code** indicates the error code. |
158| complete | () => void                           | No  | Called when **storage.get()** is complete.                              |
159
160
161## SetStorageOptions
162
163**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
164
165| Name    | Type               | Mandatory| Description                  |
166| -------- | ------------------- | ---- | -------------------- |
167| key      | string                               | Yes  | Key of the data to set.                                |
168| value    | string                               | Yes  | New value to set. The length must be less than 128 bytes.                             |
169| success  | () => void                           | No  | Called when **storage.set()** is called successfully.                     |
170| fail     | (data: string, code: number) => void | No  | Called to return the result when **storage.set()** fails to be called. **data** is the error information, and **code** indicates the error code. |
171| complete | () => void                           | No  | Called when **storage.set()** is complete.                              |
172
173
174## ClearStorageOptions
175
176**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
177
178| Name    | Type            | Mandatory| Description                        |
179| -------- | --------------------- | ---- | -------------------- |
180| success  | () => void                           | No  | Called when **storage.clear()** is called successfully.                |
181| fail     | (data: string, code: number) => void | No  | Called to return the result when **storage.clear()** fails to be called. **data** is the error information, and **code** indicates the error code. |
182| complete | () => void                           | No  | Called when **storage.clear()** is complete.                              |
183
184
185## DeleteStorageOptions
186
187**System capability**: SystemCapability.DistributedDataManager.Preferences.Core.Lite
188
189| Name    | Type                | Mandatory| Description                 |
190| -------- | -------------------- | ---- | ------------------ |
191| key      | string                               | Yes  | Key of the data to delete.                                            |
192| success  | () => void                           | No  | Called when **storage.delete()** is called successfully.               |
193| fail     | (data: string, code: number) => void | No  | Called to return the result when **storage.delete()** fails to be called. **data** is the error information, and **code** indicates the error code. |
194| complete | () => void                           | No  | Called when **storage.delete()** is complete.                              |
195