The Definitive Guide to db4o pdf

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The Definitive Guide to db4o pdf

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[...]... system, you don’t want the objects that represent your customers’ accounts to be transient— in other words, to only exist in the system’s memory If the power goes off, then you’ve got the problem of explaining to your customers that the system can’t remember how much money they have There are various methodologies for making objects persistent by storing them permanently to a durable storage device For... all there is to it There is no need to set up any database tables or define any mappings before running this code db4o just takes objects and stores them By the way, if the object you store is a structured object, the associated objects will also be stored, with no additional code The Customer object has a reference to another object representing the address, and so this Address object will also be stored... ObjectContainer—this is a db4o API class that encapsulates the database To store an object, you call the Set method of the ObjectContainer, specifying the object you want to store The two class definitions for this example are also listed (a Customer has an Address) Note that there is nothing special about these classes: db4o stores “plain” objects—ones that have no need to know about, or be altered to work with,... queries in the programming language itself, rather than an embedded “foreign” query language, are clever, useful, and truly innovative One of the main reasons for writing this book was to provide a detailed guide to what db4o is capable of and how to go about using it The other reason is the need to put db4o into the correct perspective For some situations and applications, db4o does indeed solve the persistence... having to change their characteristics or chop them up to fit into tables in the relational data model Figure 1-1 shows the difference Figure 1-1 db4o stores objects as objects, not in tables With an object database, the database schema matches the domain model very closely With a native object database the match is better than this the database schema is the domain model: objects are stored exactly as they... is, they contain references to other objects or collections of objects Therefore, you need to design your database so that the structure of your objects is stored accurately, ultimately producing an object-relational mapping between the object model and the data model The mapping needs to specify what attributes are stored where, and what relationships between the tables are required to allow the data... SQL and with db4o Chapter 14 compares the performance of db4o with that of other solutions, and describes the types of application that will gain benefits from using db4o Chapter 15 considers the business issues involved in selecting a db4o- based solution Appendix A offers a guide to db4o s graphical database browser, the ObjectManager Appendix B provides a quick reference guide to common db4o operations,... know enough about db4o to start to use it in that environment The book doesn’t try to teach C# or Java, or to go into detail about all the possible platforms that these languages and db4o support It sticks to the main objective, which is to comprehensively describe and demonstrate the db4o API and how to make the most of it For example, a db4o query returns a list of objects You can do many things with... efficient way to park a car To use a relational database to store your objects, you need to create a database table with columns matching the fields of each class that you want to persist Also, your application needs to talk a language that the database understands For example, JDBC and ADO.NET both provide the capability to embed SQL statements in code and to execute them in the database So, a customer object... object into a stream of data that can be written to and read back from a file However, while serialization is easily implemented, it is pretty limited in the way you access the information you have stored For instance, you can’t search within the data you have stored—you need to retrieve all the information in the file at once Serialization has some other limitations, too It runs into problems when the . use the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. Lead Editor:. Hörning Paterson_656-0 FRONT.fm Page i Thursday, May 4, 2006 9:51 AM The Definitive Guide to db4o Copyright © 2006 by Jim Paterson, Stefan Edlich, Henrik Hörning,

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  • The Definitive Guide to db4o

    • Contents

    • Introduction

    • PART 1 Introduction and Concepts

      • CHAPTER 1 Introduction to db4o

      • CHAPTER 2 Object-Oriented Concepts

      • CHAPTER 3 Comparing the Object and Relational Data Models

      • CHAPTER 4 OODBMS Basics

    • PART 2 Working with db4o

      • CHAPTER 5 Quick Start

      • CHAPTER 6 Querying Objects

      • CHAPTER 7 Working with Objects

      • CHAPTER 8 Client/Server Mode

      • CHAPTER 9 Transactions

      • CHAPTER 10 Configurations and Tuning

      • CHAPTER 11 Replication

      • CHAPTER 12 Advanced Issues

    • PART 3 db4o in the Real World

      • CHAPTER 13 From RDBMS to OODBMS

      • CHAPTER 14 Technical Considerations When Using db4o

      • CHAPTER 15 The Business Case for db4o

    • APPENDIX A Working with the ObjectManager

    • APPENDIX B Quick Reference

    • APPENDIX C Bibliography

    • INDEX

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