Difference between ChildObjects, ChildItem and Getcelldata in QTP

ChildObjects method is to access total child objects from an object using description object. In other words, it returns the collection of child objects contained within the object.

Syntax:- object.ChildObjects ([Description])

ChildItem method is to access child objects from a web table cell in web table object without using description object. In other words, it returns a test object from the cell by type and index. 

Syntax:-object.ChildItem (Row, Column, MicClass, Index)

Getcelldata method is to retrieve data from a web table cell in web table object.

Syntax:-object.GetCellData (Row, Column)