Working with Rules

This section describes how to create, delete, and edit your rules or decision tables in Rule Team Server.

Create a Rule

You may want to create a new rule inside an exsiting RuleDoc.

To create a new rule:

Delete a Rule

You may want to delete a rule or decision table from your RuleDoc.

Note that deleting all the rules in a RuleDoc will not delete the RuleDoc itself, as it still may contain text, images, or objects that you may want to keep. Also, you may want to keep an empty RuleDoc to preserve its history under SharePoint.

To delete a rule or decision table from an existing RuleDoc:

Editing Rules in the Rule Editor

The Rule Editor lets you edit your business rules.

The rule statements that make up a rule appear as complete phrases because they use a natural-language approach, but when constructing or editing them you see that they are made up of combinations of modifiable building blocks, which represent business terms, operators, and values. For example, in the following rule statement:

the building block the current load is a business term, is more than is an arithmetic operator, and 5000 is a value.

In the Rule Editor you construct rules from the predefined building blocks by entering text or numbers in fields, or by selecting terms in lists. Note that you can filter the choices available in the list by starting to type a word or phrase.

Furthermore, a business term may be part of a longer phrase. For example, selecting an item such as the following in your drop-down list

will require you to subsequently complete the business term <the customer> in that phrase.

Add or Remove Rule Statements

You can add or remove rule statements in order to refine your rules.

At least one action must be specified in the action part of a business rule. Consequently, you will not be able to delete the last action of a rule.

Control How Condition Statements are Combined

When the condition part of a rule contains more than one statement, you can control whether the condition part of the rule is met if all or any of its rule statements are valid.

To change how condition statements are combined:

Negate a Condition Statement

To negate a condition statement:

Open an Empty Part of a Rule

If the title of a part of a rule appears in italics, this means that it is currently empty.

To open an empty part of a rule:

Entering Values in Fields

You may want to enter a value in a field instead of selecting it from a drop-down list.

To change to a field:

Use Lists of Categories

In large business rule applications, it is possible to reduce the number of terms that appear in your drop-down lists by the use of categories.

If your application has been setup to use categories, the Rule Editor will display the Category combo box.

Select a term in the combo box to only display in your drop-down lists terms from that category.

Selecting All means that the terms from all the categories will be displayed in your drop-down lists.

Handle Error Messages

The Rule Editor will underline in red any terms that are not correct.

To remove these error messages, simply correct the term, for example by typing-in a number rather than typing-in text.

Use the Variables Defined by the Rule Editor

The Rule Editor defines one variable for each type of business term that it encounters, and identifies it with the word "the". For example, if customer is something you work with in your rules, the Rule Editor will define a variable called the customer which you can use.

If your rule requires you to refer to more than one occurrence of a customer, you have to explicitly define the other variables in the Definitions part.

Editing Rules in Decision Tables

The Decision Table Editor displays the rows and columns of your decision tables, and provides features that let you edit your rules.

It is made up of a table part, as well as a toolbar at the top that lets you access to features that either enhance readability or give you more information on your decision tables:

Preconditions, rule information, and messages are displayed just below the decision table. When you access these features, the icon disappears from the toolbar until you close the feature (by clicking the X at the top right of its display area).

Displaying rule or column information

Use the rule information icon or click directly on a row number to display the rule at the bottom of the editor in its usual If-Then form.

Similarly, placing your cursor over a column header will display in the tooltip the entire condition or action.

Expand or contract groups of rows

Sort columns

Enable paging mode

Use the paging mode icon if you want to only display a certain amount of rows at a given time rather than the entire table.

Once paging mode is enabled, you use the scrollbar at the right of the decision table to access the other pages of rules.

Click on the paging mode icon again to disable paging mode.

Add a Row

You can add rows to decision tables to create new rules (you must have the RuleDoc checked out to do so).

To add a row:

Delete a Row

You can delete rows from decision tables (you must have the RuleDoc checked out to do so).

To delete a row:

Edit a Cell

Cells are edited by either typing in values, selecting predefined values from a drop-down list, or by changing the operator that acts on a given cell.

To edit a cell:

Decision Table Errors

Rule Team Server advises you of errors in your decision table by:

Errors caused by incomplete or invalid expressions in your decision tables are signaled by a red mark, whereas errors caused by overlapping entries or entries with gaps are signaled by a blue mark. These are described as follows:

Expression Errors

Rule Team Server verifies that the values you enter in the cells of a decision table match the type of value the column expects, and that the number of arguments is correct.

For example, you get an error when you do not provide both the maximum and minimum values for a range of numbers, or if you enter text when you should enter a number.

Overlap Errors

Rule Team Server verifies that the values you enter for a given condition throughout the different rows do not overlap or are not identical.

Consider for example a column for the age of the customer:

In this example, customers that are 29 years old will satisfy the condition of both rows; this is signaled as an overlap error.

Gap Errors

Rule Team Server verifies that the cells in a condition column consider all possible cases. This ensures that there are no gaps in your tables.

Consider for example a column for the age of the customer:

In this example, customers that are 31 years old will never be taken into account; this is signaled as a gap error.

Disabling an Action Cell

It is possible to disable any action cells so that the action is not carried out for that particular row. This is equivalent to clearing the contents of the cell, except that you keep the information it contains in view of re-enabling it.

To disable an action cell:

Displaying Ruleflow

Ruleflows define the "flow" of execution of business rules and decision tables in a rule project in terms of three kinds of tasks--rule, action and flow--and the transitions between them.

Ruleflows are contained in RuleDocs and you can consult them in the Rule Editor:

Ruleflows are composed of the following parts:

Start Points and End Points

Every ruleflow has one start point and at least one end point. Start and end points are graphical markers for the start and end of a ruleflow. They do not have any functional properties.

Tasks begin executing after a ruleflow's start point, and stop executing when an end point is reached.

Tasks

A ruleflow consists of linked tasks. The tasks of a ruleflow contain the instructions for which rules to execute and in what order. Some tasks (rule tasks) contain a list of business rules and decision tables to execute. You can also have tasks that just perform actions (action tasks), and some that contain other ruleflows (flow tasks).

Initial and Final Actions

One or more actions can be attached to a task. Initial actions are applied before a task is performed, and final actions are applied after a task is performed. Initial and final actions are defined in the same way as actions for an action task.

Transitions and Transition Conditions

Transitions connect tasks in a ruleflow and define the "flow" of the ruleflow from one task to another. Transitions are unidirectional, and conditions can be attached to them.

Transition conditions provide a mechanism to control the ruleflow from task to task. Transition conditions are defined the same way as conditions in a business rule. For example, with the following condition on the transition between the Eligibility and Pricing rule tasks, the Pricing rules can only be performed when the customer is eligible, otherwise the Other Offers rule task is executed.

"Else" Paths

When a condition is added to a transition, a path with no condition must always be provided to act as the "else" path, that is, the path to take when the condition is not true must be specified.

There can be many transitions after a task. However, only one of them can be an "else" path, that is, all the transitions except the else path must have conditions. For example, in the following there are three transitions after the Eligibility rule task. If the eligibility cannot be determined using the existing information the More Information rule task is executed. If the customer is definitely eligible, the Pricing rule task is executed. An else path is provided to the Other Offers rule task for the case in which the customer is definitely not eligible.