A very busy lecture this week with Manoj introducing some index structures including:

  • ISAM – Indexed Sequential Access Mechanism
  • Binary Tree – Suseptable to ‘lopsidedness’
source week 9 lecture notes
  • B – Tree – Normalized but inconsistent lookup times.
  • B+ Tree – Normalized, all keys in leaf nodes.  Used by Oracle.
source: week 9 lecture slides

Most of the lecture was focussed on the above index structures, however we did move onto quickly cover Oracle Clusters (used to make efficient physical storage of regularly joined tables) and the Oracle Data Dictionary

Finally we tried to get through a short Advanced SQL lecutre but ended up running a bit short on time to review the more complex commands:

  • Outer Joins
  • Correleated Subqueries
  • EXISTS predicate

Pearl of the Week: Practice SQL.