15->The Table Data Geteway Pattern（weiwei 预定）

15
The Table Data
Gateway Pattern
THE PREVIOUS CHAPTER USED the Active Record pattern to create, retrieve, update, (and by
extension, delete) individual rows in a database table. Active Record is one of the simplest ways
to abstract database connectivity, but its simplicity is also its Achilles heel. An Active Record
class manages only a single row, making it inefficient for web applications that present information en
masse, such as travel booking or online shopping. In those kinds of applications―likely the majority
of all web applications―result sets are the more common currency.
The Problem
How can you easily manipulate a database table and all of the rows in that table?
The Solution
The Table Data Gateway pattern resembles the Active Record pattern. In fact, much of the code for this
new pattern is borrowed from the code in Chapter 14―The Active Record Pattern (it reuses the exact