diff --git a/en/application-dev/database/database-mdds-guidelines.md b/en/application-dev/database/database-mdds-guidelines.md index 092ec2482392a227bec109b237247dc805042d21..dd1594215a10d1c93c9825444253484ed8956e05 100644 --- a/en/application-dev/database/database-mdds-guidelines.md +++ b/en/application-dev/database/database-mdds-guidelines.md @@ -34,11 +34,14 @@ The following uses a single KV store as an example to describe the development p ``` 2. Create a **KvManager** instance based on the specified **KvManagerConfig** object. + (1) Create a **KvManagerConfig** object based on the application context. - (2) Create a **KvManager** instance. + (2) Create a **KvManager** instance. + The sample code is as follows: - ```js + + ``` let kvManager; try { const kvManagerConfig = { @@ -60,9 +63,12 @@ The following uses a single KV store as an example to describe the development p console.log("An unexpected error occurred. Error:" + e); } ``` - + + 3. Create and obtain a single KV store. + (1) Declare the ID of the single KV store to create. + (2) Create a single KV store. You are advised to disable automatic synchronization (**autoSync:false**) and call **sync** when a synchronization is required. The sample code is as follows: @@ -93,7 +99,7 @@ The following uses a single KV store as an example to describe the development p > **NOTE** > > For data synchronization between networked devices, you are advised to open the distributed KV store during application startup to obtain the database handle. With this database handle (`kvStore` in this example), you can perform operations, such as inserting data into the KV store, without creating the KV store repeatedly during the lifecycle of the handle. - + 4. Subscribe to changes in the distributed data.
The following is the sample code for subscribing to the data changes of a single KV store: ```js @@ -103,7 +109,9 @@ The following uses a single KV store as an example to describe the development p ``` 5. Write data to the single KV store. + (1) Construct the key and value to be written into the single KV store. + (2) Write key-value pairs into the single KV store. The following is the sample code for writing key-value pairs of the string type into the single KV store: @@ -125,7 +133,9 @@ The following uses a single KV store as an example to describe the development p ``` 6. Query data in the single KV store. + (1) Construct the key to be queried from the single KV store. + (2) Query data from the single KV store. The following is the sample code for querying data of the string type from the single KV store: @@ -154,8 +164,8 @@ The following uses a single KV store as an example to describe the development p > **NOTE** > > The APIs of the `deviceManager` module are system interfaces. - - The following is a code example for synchronizing data in a single KV store: + + The following is the sample code for synchronizing data in a single KV store: ```js import deviceManager from '@ohos.distributedHardware.deviceManager';