KvStore

所有已知子接口:

DeviceKvStore, SingleKvStore
```
public interface KvStore
```
Represents a key-value distributed database and provides methods for adding, deleting, modifying, querying, and subscribing to distributed data.
You can create distributed databases of different types by KvManager#getKvStore with input parameter Options. Distributed database types are defined in KvStoreType, including SingleKvStore, and DeviceKvStore.

从以下版本开始:

1

SystemCapability

SystemCapability.Data#DATA_DISTRIBUTEDDATAMGR

字段概要

字段
限定符和类型	字段	说明
`static int`	`MAX_BATCH_SIZE`	max batch operation size.
`static int`	`MAX_KEY_LENGTH`	max key length.
`static int`	`MAX_KEY_LENGTH_DEVICE`	max device coordinate key length.
`static int`	`MAX_QUERY_LENGTH`	max query length.
`static int`	`MAX_STORE_ID_LENGTH`	max store id length.
`static int`	`MAX_VALUE_LENGTH`	max value length.

方法概要

所有方法实例方法抽象方法
限定符和类型	方法	说明
`void`	`commit()`	Submits a transaction operation in the `KvStore` database.
`void`	`delete(String key)`	Deletes the key-value pair based on a specified key.
`void`	`deleteBatch(List<String> keys)`	Deletes key-value pairs in batches from the `KvStore` database.
`void`	`enableSync(boolean enabled)`	Sets whether to enable synchronization.
`String`	`getStoreId()`	Obtains the store ID of the current `KvStore` database instance.
`void`	`putBatch(List<Entry> entries)`	Inserts key-value pairs into the `KvStore` database in batches.
`void`	`putBoolean(String key, boolean value)`	Writes a key-value pair of the boolean type into the `KvStore` database.
`void`	`putByteArray(String key, byte[] value)`	Writes a key-value pair of the byte array type into the `KvStore` database.
`void`	`putDouble(String key, double value)`	Writes a key-value pair of the double type into the `KvStore` database.
`void`	`putFloat(String key, float value)`	Writes a key-value pair of the float type into the `KvStore` database.
`void`	`putInt(String key, int value)`	Writes a key-value pair of the int type into the `KvStore` database.
`void`	`putString(String key, String value)`	Writes a key-value pair of the string type into the `KvStore` database.
`void`	`rollback()`	Rolls back a transaction operation in the `KvStore` database.
`void`	`setSyncRange(List<String> localLabels, List<String> remoteSupportLabels)`	Sets synchronization range labels.
`void`	`startTransaction()`	Starts a transaction operation in the `KvStore` database.
`void`	`subscribe(SubscribeType subscribeType, KvStoreObserver observer)`	Registers a `KvStoreObserver` for the database.
`void`	`unSubscribe(KvStoreObserver observer)`	Unsubscribes from the `KvStore` database based on the specified `subscribeType` and `KvStoreObserver`.

- 字段详细资料
  - MAX_BATCH_SIZE
```
static final int MAX_BATCH_SIZE
```
    max batch operation size.
    
    另请参阅:
    
    常量字段值
  - MAX_KEY_LENGTH
```
static final int MAX_KEY_LENGTH
```
    max key length.
    
    另请参阅:
    
    常量字段值
  - MAX_KEY_LENGTH_DEVICE
```
static final int MAX_KEY_LENGTH_DEVICE
```
    max device coordinate key length.
    
    另请参阅:
    
    常量字段值
  - MAX_QUERY_LENGTH
```
static final int MAX_QUERY_LENGTH
```
    max query length.
    
    另请参阅:
    
    常量字段值
  - MAX_STORE_ID_LENGTH
```
static final int MAX_STORE_ID_LENGTH
```
    max store id length.
    
    另请参阅:
    
    常量字段值
  - MAX_VALUE_LENGTH
```
static final int MAX_VALUE_LENGTH
```
    max value length.
    
    另请参阅:
    
    常量字段值
- 方法详细资料
  - getStoreId
```
String getStoreId()
           throws KvStoreException
```
    Obtains the store ID of the current KvStore database instance.
    
    返回:
    
    Returns the store ID.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, and DB_ERROR.
    
    从以下版本开始:
    
    1
  - putBoolean
```
void putBoolean(String key,
                boolean value)
         throws KvStoreException
```
    Writes a key-value pair of the boolean type into the KvStore database.
    
    参数:
    
    key - Indicates the key. The length must be less than MAX_KEY_LENGTH. Spaces before and after the key will be cleared.
    
    value - Indicates the boolean value.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, and DB_ERROR.
    
    从以下版本开始:
    
    1
  - putInt
```
void putInt(String key,
            int value)
     throws KvStoreException
```
    Writes a key-value pair of the int type into the KvStore database.
    
    参数:
    
    key - Indicates the key. The length must be less than MAX_KEY_LENGTH. Spaces before and after the key will be cleared.
    
    value - Indicates the int value.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, and DB_ERROR.
    
    从以下版本开始:
    
    1
  - putFloat
```
void putFloat(String key,
              float value)
       throws KvStoreException
```
    Writes a key-value pair of the float type into the KvStore database.
    
    参数:
    
    key - Indicates the key. The length must be less than MAX_KEY_LENGTH. Spaces before and after the key will be cleared.
    
    value - Indicates the float value.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, and DB_ERROR.
    
    从以下版本开始:
    
    1
  - putDouble
```
void putDouble(String key,
               double value)
        throws KvStoreException
```
    Writes a key-value pair of the double type into the KvStore database.
    
    参数:
    
    key - Indicates the key. The length must be less than MAX_KEY_LENGTH. Spaces before and after the key will be cleared.
    
    value - Indicates the double value.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, and DB_ERROR.
    
    从以下版本开始:
    
    1
  - putString
```
void putString(String key,
               String value)
        throws KvStoreException
```
    Writes a key-value pair of the string type into the KvStore database.
    If you do not want to synchronize this key-value pair to other devices, set the write option in the local database.
    
    参数:
    
    key - Indicates the key. The length must be less than MAX_KEY_LENGTH. Spaces before and after the key will be cleared.
    
    value - Indicates the string value, which must be less than 4 MB as a UTF-8 byte array.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, and DB_ERROR.
    
    从以下版本开始:
    
    1
  - putByteArray
```
void putByteArray(String key,
                  byte[] value)
           throws KvStoreException
```
    Writes a key-value pair of the byte array type into the KvStore database.
    
    参数:
    
    key - Indicates the key. The length must be less than MAX_KEY_LENGTH. Spaces before and after the key will be cleared.
    
    value - Indicates the byte array, which must be less than 4 MB.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, and DB_ERROR.
    
    从以下版本开始:
    
    1
  - delete
```
void delete(String key)
     throws KvStoreException
```
    Deletes the key-value pair based on a specified key.
    
    参数:
    
    key - Indicates the key. The length must be less than MAX_KEY_LENGTH. Spaces before and after the key will be cleared.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, DB_ERROR, and KEY_NOT_FOUND.
    
    从以下版本开始:
    
    1
  - subscribe
```
void subscribe(SubscribeType subscribeType,
               KvStoreObserver observer)
        throws KvStoreException
```
    Registers a KvStoreObserver for the database. When data in the distributed database changes, the callback in KvStoreObserver will be invoked.
    
    参数:
    
    subscribeType - Indicates the subscription type, which is defined in SubscribeType.
    
    observer - Indicates the observer of data change events in the distributed database.
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, DB_ERROR, and STORE_ALREADY_SUBSCRIBE.
    
    从以下版本开始:
    
    1
  - unSubscribe
```
void unSubscribe(KvStoreObserver observer)
          throws KvStoreException
```
    Unsubscribes from the KvStore database based on the specified subscribeType and KvStoreObserver.
    
    参数:
    
    observer - Indicates the data change observer registered by #subscribe(SubscribeType, KvStoreObserver).
    
    抛出:
    
    KvStoreException - Throws this exception if any of the following errors occurs: SERVER_UNAVAILABLE, IPC_ERROR, DB_ERROR, and STORE_NOT_SUBSCRIBE.
    
    从以下版本开始:
    
    1
  - putBatch
```
void putBatch(List<Entry> entries)
       throws KvStoreException
```
    Inserts key-value pairs into the KvStore database in batches.
    
    参数:
    
    entries - Indicates the key-value pairs to be inserted in batches.
    
    抛出:
    
    KvStoreException - Throws this exception if a database error occurs.
    
    从以下版本开始:
    
    1
  - deleteBatch
```
void deleteBatch(List<String> keys)
          throws KvStoreException
```
    Deletes key-value pairs in batches from the KvStore database.
    
    参数:
    
    keys - Indicates the key-value pairs to be deleted in batches.
    
    抛出:
    
    KvStoreException - Throws this exception if a database error occurs.
    
    从以下版本开始:
    
    1
  - startTransaction
```
void startTransaction()
               throws KvStoreException
```
    Starts a transaction operation in the KvStore database.
    After the database transaction is started, you can submit or roll back the operation.
    
    抛出:
    
    KvStoreException - Throws this exception if a database error occurs.
    
    从以下版本开始:
    
    1
  - commit
```
void commit()
     throws KvStoreException
```
    Submits a transaction operation in the KvStore database.
    
    抛出:
    
    KvStoreException - Throws this exception if a database error occurs.
    
    从以下版本开始:
    
    1
  - rollback
```
void rollback()
       throws KvStoreException
```
    Rolls back a transaction operation in the KvStore database.
    
    抛出:
    
    KvStoreException - Throws this exception if a database error occurs.
    
    从以下版本开始:
    
    1
  - enableSync
```
void enableSync(boolean enabled)
         throws KvStoreException
```
    Sets whether to enable synchronization.
    
    参数:
    
    enabled - Specifies whether to enable synchronization. The value true means to enable synchronization, and false means the opposite.
    
    抛出:
    
    KvStoreException - Throws this exception if an internal service error occurs.
    
    从以下版本开始:
    
    4
  - setSyncRange
```
void setSyncRange(List<String> localLabels,
                  List<String> remoteSupportLabels)
           throws KvStoreException
```
    Sets synchronization range labels.
    The labels determine the devices with which data will be synchronized.
    
    参数:
    
    localLabels - Indicates the synchronization labels of the local device.
    
    remoteSupportLabels - Indicates the labels of the devices with which data will be synchronized.
    
    抛出:
    
    KvStoreException - Throws this exception if an internal service error occurs.
    
    从以下版本开始:
    
    4

接口 KvStore

字段概要

方法概要

字段详细资料

MAX_BATCH_SIZE

MAX_KEY_LENGTH

MAX_KEY_LENGTH_DEVICE

MAX_QUERY_LENGTH

MAX_STORE_ID_LENGTH

MAX_VALUE_LENGTH

方法详细资料

getStoreId

putBoolean

putInt

putFloat

putDouble

putString

putByteArray

delete

subscribe

unSubscribe

putBatch

deleteBatch

startTransaction

commit

rollback

enableSync

setSyncRange