Glossary


In this book, I've tried to be precise and consistent in my use of terms. The terms come from many sources, including the JDO specification and other specifications for the Java platform. In some cases, they are common in the industry, and you can look them up in the Free On-Line Dictionary of Computing. To find this wonderful resource on the Web, search for the word "FOLDOC". In some cases, I have invented my own terms. Although the terms are defined as they are introduced in the book, their definitions are collected together here for your convenience.

A

ACID Properties

Acronym for Atomicity, Consistency, Isolation, and Durability. Transactions are atomic if a series of change requests can be combined into one all-or-nothing request. The transactional service either accepts all changes or returns an error when the user commits the transaction. The service rejects all changes when the user rolls back the transaction. Transactions are consistent if at the beginning of the transaction and at the end of the transaction the service has enforced the defined data constraints. The service may impose its own constraints, and it may allow the user to define additional constraints. If the service allows concurrent transactions, then the transactions are isolated if the modifications made in one transaction are visible to another transaction only in clearly defined ways. Finally, transactions are durable if the work of committed transactions is never lost. The durability guarantee assumes that the media that stores the information is not lost, and it does not prevent a later transaction from undoing the work of an earlier transaction.

API

Application Programming Interface. Refers to both the specification for a library of services that applications can use, and, informally, another name for the library itself.

Application data class

A class defined by the application whose primary purpose is to hold state that can be stored and retrieved from the datastore. Application data classes must be enhanced to support the PersistenceCapable interface before JDO can manage objects of their type.

Application data object

An instance of an application data class.




Using and Understanding Java Data Objects
Using and Understanding Java Data Objects
ISBN: 1590590430
EAN: 2147483647
Year: 2005
Pages: 156
Authors: David Ezzio

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