《Oracle数据库规则管理器和表达式开发人员指南》

需积分: 5 15 浏览量更新于2024-01-27 收藏 1.14MB PDF 举报

Oracle Database Rules Manager and Expression Developer's Guide是一本关于Oracle数据库的规则管理器和表达式开发人员指南。该指南提供了有关使用Oracle Database中的规则管理器和表达式过滤器的详细信息。这本指南适用于Oracle Database 11g Release 2（11.2）版本，并且具有权威的版权信息。在这本指南中，主要作者是Aravind Yalamanchi和Rod Ward，还有其他几位贡献者，如William Beauregard、Timothy Chorma、Dieter Gawlick、Helen Grembowicz、Lory Molesky和Deborah Ow。他们的专业知识和经验为读者提供了宝贵的指导。这本指南主要围绕Oracle数据库中的规则管理器和表达式过滤器展开，这是一个强大的工具，可以帮助开发人员管理和应用各种规则和约束。规则管理器允许开发人员通过定义和管理规则来提高数据库的性能和可用性。表达式过滤器则可以帮助开发人员在查询中应用自定义表达式以过滤数据。该指南的内容包括规则管理器和表达式过滤器的概述、安装和配置、使用指南以及高级主题。读者可以学习如何定义和管理规则，如何使用表达式过滤器进行查询优化，以及如何处理常见的问题和错误。此外，该指南还提供了详细的示例和实用技巧，帮助读者更好地理解和应用规则管理器和表达式过滤器。读者可以通过阅读实际案例和实践任务来巩固自己的知识，并将其应用到实际项目中。总之，Oracle Database Rules Manager and Expression Developer's Guide是一本全面而且实用的指南，适用于想要深入了解和应用Oracle数据库规则管理器和表达式过滤器的开发人员。阅读这本指南可以帮助读者提高数据库的性能和可用性，并在开发过程中遇到问题时提供解决方案。无论是初学者还是有经验的开发人员，都可以从这本指南中获得很多有价值的知识和技巧。

What is a Rule?

1-2 Oracle Database Rules Manager and Expression Filter Developer’s Guide

If you have an existing Expression Filter application and want to upgrade it to a Rules

Manager application, first see Section D.1, which describes an implementation of

Expression Filter and Rules Manager. Next, see Section D.2, which describes the

process of upgrading an Expression Filter application to a Rules Manager application.

1.1 What is a Rule?

A rule is a directive to guide or influence a process behavior. A rule consists of a

conditional expression that you specify using the attributes you define in a

corresponding event structure. When an instance of the event structure satisfies a rule

condition, a rule action takes place. When the rule action executes, event management

policies define how to handle an event instance. This, in a nutshell, describes how a

typical rules-based system works.

Typically, rules follow Event-Condition-Action (ECA) rule semantics where an event

happens and if a rule condition evaluates to true for this event, then it performs some

prescribed action. The ECA components are defined as:

■ Event -- the state information for the process

■ Condition -- the Boolean condition that evaluates to true or false for the event

■ Action -- the action to be carried out if the rule condition evaluates to true for the

event

The standard notation for ECA rules is:

ON <event structure>

IF <condition>

THEN <action>

where, the ON clause identifies the event structure for which the rule is defined, the IF

clause specifies the rule condition, and the THEN clause specifies the rule action.

An example of a rule is the following: If a customer chose to fly Abcair Airlines to

Orlando and if his stay in Orlando is more than 7 days, then offer an Acar rental car

promotion to him. Using the ECA notation, this rule is:

AddFlight (Custid, Airline, FromCity, ToCity, Depart, Return)

Airline = 'Abcair' and ToCity = 'Orlando' and Return-Depart >= 7

THEN

OfferPromotion (CustId, 'RenralCar', 'Acar')

where:

The ON clause identifies the event structure for this rule.

The IF clause defines the rule condition using variables in the event structure.

The THEN clause defines the commands that represent the action for this rule.

Rules Manager

Rules Manager, a feature of Oracle Database, offers interfaces to define, manage, and

enforce complex rules in the database. The five elements of a Rules Manager

application are:

1. An event structure you define as an object type with attributes that describe

specific features of an event.

2. A rule consists of a condition and action preferences.

Developing Rules Applications

1-4 Oracle Database Rules Manager and Expression Filter Developer’s Guide

1.2 Developing Rules Applications

Developing a rules application using Rules Manager requires a somewhat different

approach toward application development. Typically, you would scan through a new

API and other reference material, then create some sample scripts based on the

examples to get a feel for how the feature works. Next, you might begin to apply these

methods learned to your own application. However, this is where you might get

bogged down in the detail of the implementation because the approach to Rules

Manager application development uses a somewhat different focus. The focus is on

the decision points that already exist in your application and that is all. You need not

focus on all the supporting parts of your application that do not necessarily pertain to

these decision points.

As an application developer you must ask yourself the following questions:

■ Where are the decision points in my application?

■ What are the decisions that each decision point is making?

■ How is each decision being made?

■ Once a decision is made how does it execute in the application?

Note that each decision point may use one or more rules that may involve one or more

events happening in some sequence.

Once you determine the decision points in your application, you integrate Rules

Manager into your application by using the standard notation for ECA rules to model

each decision point as described in Section 1.1. It is best to keep your approach as

simple as possible.

For example, using Rules Manager for the simplest case, if your application has a

decision point that uses one or more rules each relying on a single instance of an event

structure that happens in the application, you would define a primitive event structure

to model this event activity. In a complex event scenario, if your application has

another decision point that uses one or more rules, each relying on multiple instances

of the same or different event structures that happen in some sequence, define a

composite event structure consisting of separately defined primitive event structures

for each individual event that happens. The composite event structure couples these

primitive events together to model the composite event activity. Next, create the rule

class. Creating the rule class implicitly creates the rule class table containing an

expression column to store the rule conditions and one or more action preferences

columns you use to determine the appropriate action when the rule evaluates to true.

In addition to the rule class table, the previous step also creates an action callback

procedure that you can modify to execute the action for the matching rules.

This unique approach lets you quickly integrate Rules Manager into existing

applications as easily as if it were a new application because you only need to focus on

the decision points contained in your application or in your data analysis for a new

application. Remember Rules Manager stores, processes, and matches rules with

instances of either incoming single events or groups of events to resolve the rules

concentrated around each decision point. The object then becomes how best to model

these decision points using Rules Manager. This is explained in Part I, "Rules

Manager".

剩余197页未读，继续阅读

weixin_40191861_zj

粉丝: 83
资源: 1万+

《Oracle数据库规则管理器和表达式开发人员指南》

Oracle Database Backup and Recovery User's Guide.pdf

Oracle Database Object-Relational Developer's Guide 11g Release

Oracle Database 2 Day + Java Developer’s Guide 11g Release 2-138

Oracle Database Advanced Application Developer's Guide 11g Relea

Oracle Database 2 Day Developer's Guide 11g Release 2

Oracle Database 2 Day Developer's Guide 11g Release 2 (11.2

Oracle Database 11g SQL Developer's Guide

Oracle Database Workspace Manager Developer's Guide 11g Release 2 (11.2) - 340: 了解Oracle Workspace...

Oracle Database 2 Day + Application Express Developer’s Guide

Oracle DatabaseWorkspace Manager Developer's Guide 11g Release 2

最新资源