Vertical partitioning for large tables to reduce I/O and cache requirements — separate columns that are queried often vs rarely. Adding a column to a production system when the alter table is “too expensive”. Super-type/subtype pattern. Vertical partitioning to benefit from table (join) elimination — providing optimizer supports it (again to reduce I/O and cache) … Read more
Create a diagram for existing database schema or its subset as follows: Click File → Data Modeler → Import → Data Dictionary. Select a DB connection (add one if none). Click Next. Check one or more schema names. Click Next. Check one or more objects to import. Click Next. Click Finish. The ERD is displayed. … Read more
Survey Database Design Last Update: 5/3/2015 Diagram and SQL files now available at https://github.com/durrantm/survey If you use this (top) answer or any element, please add feedback on improvements !!! This is a real classic, done by thousands. They always seems ‘fairly simple’ to start with but to be good it’s actually pretty complex. To do … Read more
ER Notation There are several ER notations. I’m not familiar with the one you are using, but it’s clear enough you are trying to represent a subtype (aka. inheritance, category, subclass, generalization hierarchy…). This is the relational cousin of the OOP inheritance. When doing subtyping, you are generally concerned with the following design decisions: Abstract … Read more