O'Reilly logo

Joe Celko's Trees and Hierarchies in SQL for Smarties, 2nd Edition by Joe Celko

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 5. Frequent Insertion Trees
The problem in a nested sets tree with frequent insertions is that the (lft, rgt) pairs have to be adjusted so often that locking the table, changing the rows, and unlocking the table again become a major overhead. The nested sets model does not require that the union of rgt and lft numbers be an unbroken sequence to show nesting. All you need is the condition that (lft < rgt), uniqueness of lft and rgt numbers, and that subordination is represented by containment of one (lft, rgt) pair within the ranges of the other (lft, rgt) pairs.
Keywords: floating point numbers, spread, data type, reorganization, rational numbers, nested intervals model, depth-first convergence point, breadth-first convergence point, depth-first ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required