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MySQL NDB Cluster API Developer Guide
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2.3.15 The Key_part_ptr Structure


This section describes the Key_part_ptr structure.

Parent class.  Ndb

Description.  Key_part_ptr provides a convenient way to define key-part data when starting transactions and computing hash values, by passing in pointers to distribution key values. When the distribution key has multiple parts, they should be passed as an array, with the last part's pointer set equal to NULL. See Section, “Ndb::startTransaction()”, and Section, “Ndb::computeHash()”, for more information about how this structure is used.

Attributes.  A Key_part_ptr has the attributes shown in the following table:

Table 2.29 Key_part_ptr structure attributes, with types, initial values, and descriptions

Attribute Type Initial Value Description
ptr const void* none Pointer to one or more distribution key values
len unsigned none The length of the pointer