Essential Sqlalchemy

by Copeland, Rick

• ISBN13: 9780596516147
• ISBN10: 0596516142
• Format: Paperback
• Copyright: 2008-06-01
• Publisher: Oreilly & Associates Inc

Summary

Essential SQLAlchemy introduces a high-level open-source code library that makes it easier for Python programmers to access relational databases such as Oracle, DB2, MySQL, PostgreSQL, and SQLite. SQLAlchemy has become increasingly popular since its release, but it still lacks good offline documentation. This practical book fills the gap, and because a developer wrote it, you get an objective look at SQLAlchemy's tools rather than an advocate's description of all the cool features. SQLAlchemy includes both a database server-independent SQL expression language and an object-relational mapper (ORM) that lets you map "plain old Python objects" (POPOs) to database tables without substantially changing your existing Python code. Essential SQLAlchemy demonstrates how to use the library to create a simple database application, walks you through simple queries, and explains how to use SQLAlchemy to connect to multiple databases simultaneously with the same Metadata.

Author Biography

Rick Copeland is a senior software engineer with retail analytics firm Predictix, LLC, where he uses SQLAlchemy extensively, primarily for web application development. He has been using Python full-time for development since 2005, in projects as diverse as demand forecasting, business web applications, compilers, and hardware synthesis.

Table of Contents

Preface	p. vii
Introduction to SQLAlchemy	p. 1
What Is SQLAlchemy	p. 1
The Object/Relational "Impedance Mismatch"	p. 4
SQLAlchemy Philosophy	p. 7
SQLAlchemy Architecture	p. 10
Getting Started	p. 21
Installing SQLAlchemy	p. 21
SQLAlchemy Tutorial	p. 24
Engines and MetaData	p. 33
Engines and Connectables	p. 33
MetaData	p. 39
SQLAlchemy Type Engines	p. 59
Type System Overview	p. 59
Built-in Types	p. 59
Application-Specific Custom Types	p. 63
Running Queries and Updates	p. 67
Inserts, Updates, and Deletes	p. 67
Queries	p. 72
Building an Object Mapper	p. 93
Introduction to ORMs	p. 93
Declaring Object Mappers	p. 95
Declaring Relationships Between Mappers	p. 107
Extending Mappers	p. 120
ORM Partitioning Strategies	p. 121
Querying and Updating at the ORM Level	p. 127
The SQLAlchemy ORM Session Object	p. 127
Querying at the ORM Level	p. 139
Contextual or Thread-Local Sessions	p. 153
Inheritance Mapping	p. 157
Overview of Inheritance Mapping	p. 157
Single Table Inheritance Mapping	p. 158
Concrete Table Inheritance Mapping	p. 161
Joined Table Inheritance Mapping	p. 163
Relations and Inheritance	p. 167
Elixir: A Declarative Extension to SQLAlchemy	p. 171
Introduction to Elixir	p. 171
Installing Elixir	p. 174
Using Elixir	p. 174
Elixir Extensions	p. 184
SqlSoup: An Automatic Mapper for SQLAlchemy	p. 189
Introduction to SqlSoup	p. 189
Using SqlSoup for ORM-Style Queries and Updates	p. 191
Using SqlSoup for SQL-Level Inserts, Updates, and Deletes	p. 195
When to Use SqlSoup Versus Elixir Versus "Bare" SQLAlchemy	p. 195
Other SQLAlchemy Extensions	p. 199
Association Proxy	p. 199
Ordering List	p. 203
Deprecated Extensions	p. 205
Index	p. 207
Table of Contents provided by Ingram. All Rights Reserved.