2.3.17 The NdbIndexOperation Class

NdbIndexOperation Class Overview

Parent class

NdbOperation

Child classes

None

Description

NdbIndexOperation represents an index operation for use in transactions. This class inherits from NdbOperation.

NdbIndexOperation can be used only with unique hash indexes; to work with ordered indexes, use NdbIndexScanOperation.

This class has no public constructor. To create an instance of NdbIndexOperation, it is necessary to use the NdbTransaction::getNdbIndexOperation() method.

Methods

The following table lists the public methods of this class and the purpose or use of each method:

Table 2.44 NdbIndexOperation class methods and descriptions

Name	Description
`deleteTuple()`	Removes a tuple from a table
`getIndex()`	Gets the index used by the operation
`readTuple()`	Reads a tuple from a table
`updateTuple()`	Updates an existing tuple in a table

Index operations are not permitted to insert tuples.

Types

The NdbIndexOperation class defines no public types of its own.

For more information about the use of NdbIndexOperation, see Section 1.4.2.3.2, “Single-row operations”.

NdbIndexOperation::deleteTuple()

Description

This method defines the NdbIndexOperation as a DELETE operation. When the NdbTransaction::execute() method is invoked, the operation deletes a tuple from the table.

Signature

int deleteTuple
    (
      void
    )

Parameters

None.

Return value

0 on success, -1 on failure.

NdbIndexOperation::getIndex()

Description

Gets the index, given an index operation.

Signature

const NdbDictionary::Index* getIndex
    (
      void
    ) const

Parameters

None.

Return value

A pointer to an Index object.

NdbIndexOperation::readTuple()

Description

This method defines the NdbIndexOperation as a READ operation. When the NdbTransaction::execute() method is invoked, the operation reads a tuple.

Signature

int readTuple
    (
      LockMode mode
    )

Parameters

mode specifies the locking mode used by the read operation. See NdbOperation::LockMode, for possible values.

Return value

0 on success, -1 on failure.

NdbIndexOperation::updateTuple()

Description

This method defines the NdbIndexOperation as an UPDATE operation. When the NdbTransaction::execute() method is invoked, the operation updates a tuple found in the table.

Signature

int updateTuple
    (
      void
    )

Parameters

None.

Return value

0 on success, -1 on failure.