2.3.9 The GetValueSpec Structure

Parent class.  NdbOperation

Description.  This structure is used to specify an extra value to obtain as part of an NdbRecord operation.

Members.  The makeup of this structure is shown here:

Figure 2.7 NdbOperation::GetValueSpec

NdbOperation::GetValueSpec structure

The individual members are described in more detail in the following table:

columnconst Column*To specify an extra value to read, the caller must provide this, as well as (optionally NULL) appStorage pointer.
appStoragevoid*If this pointer is null, then the received value is stored in memory managed by the NdbRecAttr object. Otherwise, the received value is stored at the location pointed to (and is still accessable using the NdbRecAttr object).

It is the caller's responsibility to ensure that the following conditions are met:

  1. appStorage points to sufficient space to store any returned data.

  2. Memory pointed to by appStorage is not reused or freed until after the execute() call returns.

recAttrNdbRecAttr*After the operation is defined, recAttr contains a pointer to the NdbRecAttr object for receiving the data.

Currently, blob reads cannot be specified using GetValueSpec.

For more information, see Section 2.3.27, “The NdbRecord Interface”.