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4.18.2.5 NdbScanOperation::updateCurrentTuple() »
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4.18.2.4. NdbScanOperation::lockCurrentTuple()

Description.  This method locks the current tuple.

Signature.  

NdbOperation* lockCurrentTuple
    (
      void
    )

or 

NdbOperation* lockCurrentTuple
    (
      NdbTransaction* lockTrans
    )

Beginning with MySQL Cluster NDB 6.2.3, the following signature is also supported for this method, when using NdbRecord: 

NdbOperation *lockCurrentTuple
    (
      NdbTransaction* takeOverTrans,
      const NdbRecord* record,
      char* row = 0,
      const unsigned char* mask = 0
    )

Parameters.  This method takes a single, optional parameter — the transaction that should perform the lock. If this is omitted, the transaction is the current one.

Parameters when using NdbRecord.  When using the NdbRecord interface (see Section 4.25, “The NdbRecord Interface”), this method takes these parameters, as described in the following list:

  • The transaction (takeOverTrans) that should perform the lock; when using NdbRecord with scans, this parameter is not optional.

  • The NdbRecord referenced by the scan. This is required, even if no records are being read.

  • The row from which to read. Set this to NULL if no read is to occur.

  • The mask pointer is optional. If it is present, then only columns for which the corresponding bit in the mask is set are retrieved by the scan.

Important

Calling an NdbRecord scan lock takeover on an NdbRecAttr-style scan is not valid, nor is calling an NdbRecAttr-style scan lock takeover on an NdbRecord-style scan.

Return Value.  This method returns a pointer to an NdbOperation object, or NULL. (See Section 4.15, “The NdbOperation Class”.)