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Objects

Item Pointer Object

Description

The Item Pointer object is used to store a pointer to a data item (or 'item' for short). An 'item' is either a record or a field.

The function fhNewItemPtr can be used to create a new Item Pointer object.  The function fhGetValueAsLink returns the value of a link field as an Item Pointer object (link fields store links to other records).

See also Item Pointers: Confusions and Pitfalls to Avoid.

Summary

The Item Pointer object has the following methods:

Understanding the Tree Structure

  • INDI
    • NAME
    • BIRT
      • DATE
      • PLAC
      • SOUR
    • BAPT
      • DATE
      • PLAC
      • SOUR

Family Historian stores your family tree data in a tree structure similar to that used by GEDCOM.

Data items have a hierarchical structure.  Items can be owned by other items. All fields are owned by a record, or by another field.  Records are not owned.  The relationship between the items therefore can be one of the following:

  • Parent
  • Sibling
  • Child
In the example given in the box on the right, INDI is the parent of the NAME, BIRT and BAPT fields.  The NAME, BIRT and BAPT fields are siblings. Be aware though that the terms 'parent', 'child' and 'sibling', are used metaphorically in this context to refer to the hierarchical relationships between items in a data structure, and have nothing to do with relationships between people.

Note, that the first set of DATE, PLAC and SOUR items (children of the BIRT item) are siblings.  What makes them siblings is that they share the same parent (the BIRT item in this case).  So none of them are siblings of the DATE, PLAC, or SOUR items in the second group (the children of the BAPT item).

See the following sample for an example of the use of item pointers.

Links to

Linked from