Introduction to Schema API
The Schema API allows modules to declare their database tables in a structured array (similar to the Form API) and provides API functions
Schema API quick start guide
A sample schema data structure
Schema Reference
A Drupal schema definition is an array structure representing one or more tables and their related keys and indexes. A schema is defined by
Schema API functions
The Schema API defines a number of functions for manipulating the database schema. These functions all operate directly on the database at
Updating tables: hook_update_N() functions
As in previous versions of Drupal, you can update database tables for new versions using a hook_update_N() function. Note that when you
Data types
Detailed documentation on all the data types supported by Drupal's Schema API.