Transaction (H2 Database Engine 2.0.0 API)

java.lang.Object
- org.h2.mvstore.tx.Transaction

public final class Transaction
extends Object

A transaction.

字段概要

字段
限定符和类型	字段和说明
`static int`	`STATUS_CLOSED` The status of a closed transaction (committed or rolled back).
`static int`	`STATUS_COMMITTED` The status of a transaction that has been logically committed or rather marked as committed, because it might be still listed among prepared, if it was prepared for commit.
`static int`	`STATUS_OPEN` The status of an open transaction.
`static int`	`STATUS_PREPARED` The status of a prepared transaction.

方法概要

所有方法实例方法具体方法
限定符和类型	方法和说明
`boolean`	`allowNonRepeatableRead()` Whether this transaction has isolation level READ_COMMITTED or below.
`void`	`commit()` Commit the transaction.
`int`	`getBlockerId()`
`Iterator<TransactionStore.Change>`	`getChanges(long savepointId)` Get the list of changes, starting with the latest change, up to the given savepoint (in reverse order than they occurred).
`int`	`getId()`
`IsolationLevel`	`getIsolationLevel()` Returns the isolation level of this transaction.
`String`	`getName()`
`long`	`getSequenceNum()`
`int`	`getStatus()`
`boolean`	`hasChanges()` Determine if any database changes were made as part of this transaction.
`boolean`	`hasStatementDependencies()` Returns whether statement dependencies are currently set.
`void`	`markStatementEnd()` Mark an exit from SQL statement execution within this transaction.
`void`	`markStatementStart(HashSet<MVMap<Object,VersionedValue<Object>>> maps)` Mark an entry into a new SQL statement execution within this transaction.
`<K,V> TransactionMap<K,V>`	`openMap(String name)` Open a data map.
`<K,V> TransactionMap<K,V>`	`openMap(String name, DataType<K> keyType, DataType<V> valueType)` Open the map to store the data.
`<K,V> TransactionMap<K,V>`	`openMapX(MVMap<K,VersionedValue<V>> map)` Open the transactional version of the given map.
`void`	`prepare()` Prepare the transaction.
`<K,V> void`	`removeMap(TransactionMap<K,V> map)` Remove the map.
`void`	`rollback()` Roll the transaction back.
`void`	`rollbackToSavepoint(long savepointId)` Roll back to the given savepoint.
`void`	`setName(String name)`
`long`	`setSavepoint()` Create a new savepoint.
`void`	`setTimeoutMillis(int timeoutMillis)` Sets the new lock timeout.
`String`	`toString()`
`boolean`	`waitFor(Transaction toWaitFor, String mapName, Object key)` Make this transaction to wait for the specified transaction to be closed, because both of them try to modify the same map entry.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- 字段详细资料
  - STATUS_CLOSED
```
public static final int STATUS_CLOSED
```
    The status of a closed transaction (committed or rolled back).
    
    另请参阅:
    
    常量字段值
  - STATUS_OPEN
```
public static final int STATUS_OPEN
```
    The status of an open transaction.
    
    另请参阅:
    
    常量字段值
  - STATUS_PREPARED
```
public static final int STATUS_PREPARED
```
    The status of a prepared transaction.
    
    另请参阅:
    
    常量字段值
  - STATUS_COMMITTED
```
public static final int STATUS_COMMITTED
```
    The status of a transaction that has been logically committed or rather marked as committed, because it might be still listed among prepared, if it was prepared for commit. Undo log entries might still exists for it and not all of it's changes within map's are re-written as committed yet. Nevertheless, those changes should be already viewed by other transactions as committed. This transaction's id can not be re-used until all of the above is completed and transaction is closed. A transactions can be observed in this state when the store was closed while the transaction was not closed yet. When opening a store, such transactions will automatically be processed and closed as committed.
    
    另请参阅:
    
    常量字段值
- 方法详细资料
  - getId
```
public int getId()
```
  - getSequenceNum
```
public long getSequenceNum()
```
  - getStatus
```
public int getStatus()
```
  - hasChanges
```
public boolean hasChanges()
```
    Determine if any database changes were made as part of this transaction.
    
    返回:
    
    true if there are changes to commit, false otherwise
  - setName
```
public void setName(String name)
```
  - getName
```
public String getName()
```
  - getBlockerId
```
public int getBlockerId()
```
  - setSavepoint
```
public long setSavepoint()
```
    Create a new savepoint.
    
    返回:
    
    the savepoint id
  - hasStatementDependencies
```
public boolean hasStatementDependencies()
```
    Returns whether statement dependencies are currently set.
    
    返回:
    
    whether statement dependencies are currently set
  - getIsolationLevel
```
public IsolationLevel getIsolationLevel()
```
    Returns the isolation level of this transaction.
    
    返回:
    
    the isolation level of this transaction
  - allowNonRepeatableRead
```
public boolean allowNonRepeatableRead()
```
    Whether this transaction has isolation level READ_COMMITTED or below.
    
    返回:
    
    true if isolation level is READ_COMMITTED or READ_UNCOMMITTED
  - markStatementStart
```
public void markStatementStart(HashSet<MVMap<Object,VersionedValue<Object>>> maps)
```
    Mark an entry into a new SQL statement execution within this transaction.
    
    参数:
    
    maps - set of maps used by transaction or statement is about to be executed
  - markStatementEnd
```
public void markStatementEnd()
```
    Mark an exit from SQL statement execution within this transaction.
  - openMap
```
public <K,V> TransactionMap<K,V> openMap(String name)
```
    Open a data map.
    
    类型参数:
    
    K - the key type
    
    V - the value type
    
    参数:
    
    name - the name of the map
    
    返回:
    
    the transaction map
  - openMap
```
public <K,V> TransactionMap<K,V> openMap(String name,
                                         DataType<K> keyType,
                                         DataType<V> valueType)
```
    Open the map to store the data.
    
    类型参数:
    
    K - the key type
    
    V - the value type
    
    参数:
    
    name - the name of the map
    
    keyType - the key data type
    
    valueType - the value data type
    
    返回:
    
    the transaction map
  - openMapX
```
public <K,V> TransactionMap<K,V> openMapX(MVMap<K,VersionedValue<V>> map)
```
    Open the transactional version of the given map.
    
    类型参数:
    
    K - the key type
    
    V - the value type
    
    参数:
    
    map - the base map
    
    返回:
    
    the transactional map
  - prepare
```
public void prepare()
```
    Prepare the transaction. Afterwards, the transaction can only be committed or completely rolled back.
  - commit
```
public void commit()
```
    Commit the transaction. Afterwards, this transaction is closed.
  - rollbackToSavepoint
```
public void rollbackToSavepoint(long savepointId)
```
    Roll back to the given savepoint. This is only allowed if the transaction is open.
    
    参数:
    
    savepointId - the savepoint id
  - rollback
```
public void rollback()
```
    Roll the transaction back. Afterwards, this transaction is closed.
  - getChanges
```
public Iterator<TransactionStore.Change> getChanges(long savepointId)
```
    Get the list of changes, starting with the latest change, up to the given savepoint (in reverse order than they occurred). The value of the change is the value before the change was applied.
    
    参数:
    
    savepointId - the savepoint id, 0 meaning the beginning of the transaction
    
    返回:
    
    the changes
  - setTimeoutMillis
```
public void setTimeoutMillis(int timeoutMillis)
```
    Sets the new lock timeout.
    
    参数:
    
    timeoutMillis - the new lock timeout in milliseconds
  - waitFor
```
public boolean waitFor(Transaction toWaitFor,
                       String mapName,
                       Object key)
```
    Make this transaction to wait for the specified transaction to be closed, because both of them try to modify the same map entry.
    
    参数:
    
    toWaitFor - transaction to wait for
    
    mapName - name of the map containing blocking entry
    
    key - of the blocking entry
    
    返回:
    
    true if other transaction was closed and this one can proceed, false if timed out
  - removeMap
```
public <K,V> void removeMap(TransactionMap<K,V> map)
```
    Remove the map.
    
    类型参数:
    
    K - the key type
    
    V - the value type
    
    参数:
    
    map - the map
  - toString
```
public String toString()
```
    覆盖:
    
    toString 在类中 Object

类 Transaction

字段概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

STATUS_CLOSED

STATUS_OPEN

STATUS_PREPARED

STATUS_COMMITTED

方法详细资料

getId

getSequenceNum

getStatus

hasChanges

setName

getName

getBlockerId

setSavepoint

hasStatementDependencies

getIsolationLevel

allowNonRepeatableRead

markStatementStart

markStatementEnd

openMap

openMap

openMapX

prepare

commit

rollbackToSavepoint

rollback

getChanges

setTimeoutMillis

waitFor

removeMap

toString