TTXlaTableHandler Reference

The TTXlaTableHandler class provides methods that enable and disable change tracking for a table. Methods are also provided to handle update notification records from XLA.

Also see TTXlaTableHandler Usage.

Public Members

None

Protected Members

Member	Description
`TTXlaTable tbl`	This is for the metadata associated with the table being handled.
`TTXlaRowViewer row`	This is used to view the row being inserted or deleted, or the old image of the row being updated, in user-written `HandleInsert()`, `HandleDelete()`, and `HandleUpdate()` methods.
`TTXlaRowViewer row2`	This is used to view the new image of the row being updated in user-written `HandleUpdate()` methods.

Public Methods

This section summarizes then describes the TTXlaTableHandler public methods.

Public methods summary

Method	Description
`DisableTracking()`	Disables XLA update tracking for the table.
`EnableTracking()`	Enables XLA update tracking for the table.
`generateSQL()`	Returns the SQL associated with a given XLA record.
`HandleChange()`	Dispatches a record from `ttXlaUpdateDesc_t` to the appropriate handling routine for processing.
`HandleDelete()`	This is invoked when the `HandleChange()` method is called to process a delete operation.
`HandleInsert()`	This is invoked when the `HandleChange()` method is called to process an insert operation.
`HandleUpdate()`	This is invoked when the `HandleChange()` method is called to process an update operation.

DisableTracking()

virtual void DisableTracking()

Disables XLA update tracking for the table. After this method is called, the XLA bookmark no longer captures information about changes to the table.

EnableTracking()

virtual void EnableTracking()

Enables XLA update tracking for the table. Until this method is called, the XLA bookmark does not capture information about changes to the table.

generateSQL()

void generateSQL (ttXlaUpdateDesc_t* updateDescP, char* buffer, 
                  SQLINTEGER maxByteLen, SQLINTEGER* actualByteLenP)

This method prints the SQL associated with a given XLA record. The SQL string is returned through the buffer parameter. Allocate space for the buffer and specify its maximum length, maxByteLen. The actualByteLenP parameter returns information about the actual length of the SQL string returned.

If maxByteLen is less than the length of the generated SQL string, a TTStatus error is thrown and the contents of buffer and actualByteLenP are not modified.

HandleChange()

virtual void HandleChange(ttXlaUpdateDesc_t* updateDescP)
virtual void HandleChange(ttXlaUpdateDesc_t* updateDescP, void* pData)

Dispatches a ttXlaUpdateDesc_t object to the appropriate handling routine for processing. The update description is analyzed to determine if it is for a delete, insert or update operation. The appropriate handing method is then called: HandleDelete(), HandleInsert(), or HandleUpdate().

Classes that inherit from TTXlaTableHandler can use the optional pData parameter when they overload the TTXlaTableHandler::HandleChange() method. This optional parameter is useful for determining whether the batch of XLA records that was just processed ends on a transaction boundary. Knowing this helps an application decide the appropriate time to invoke TTConnection::ackUpdates(). See Acknowledging XLA Updates at Transaction Boundaries for an example that uses the pData parameter.

Also see HandleChange() for TTXlaTableList objects.

HandleDelete()

virtual void HandleDelete(ttXlaUpdateDesc_t* updateDescP) = 0

This method is invoked whenever the HandleChange() method is called to process a delete operation.

HandleDelete() is not implemented in the TTXlaTableHandler base class. It must be implemented by any classes derived from it, with appropriate logic to handle deleted rows.

The row that was deleted from the table is available through the protected member row of type TTXlaRowViewer.

HandleInsert()

virtual void HandleInsert(ttXlaUpdateDesc_t* updateDescP) = 0

This method is invoked whenever the HandleChange() method is called to process an insert operation.

HandleInsert() is not implemented in the TTXlaTableHandler base class. It must be implemented by any classes derived from it, with appropriate logic to handle inserted rows.

The row that was inserted into the table is available through the protected member row of type TTXlaRowViewer.

HandleUpdate()

virtual void HandleUpdate(ttXlaUpdateDesc_t* updateDescP) = 0

This method is invoked whenever the HandleChange() method is called to process an update operation.

HandleUpdate() is not implemented in the TTXlaTableHandler base class. It must be implemented by any classes derived from it, with appropriate logic to handle updated rows.

The previous version of the row that was updated from the table is available through the protected member row of type TTXlaRowViewer. The new version of the row is available through the protected member row2, also of type TTXlaRowViewer.