Power Designer n See course web page for additional information on using Power Designer n Business rules – Come from a description of activities – Example “Each author of a book receives a certain percentage of royalties. Royalty fees are calculated as a percentage of sales, and the percentage of royalties increases with the number of books sold.”

Power Designer n Types of business rules – Facts -- a publisher publishes 1 or more titles n ER diagram will take care of these – Definition -- explanation of a field – Formula -- royalty fees are 10 percent of sales – Validation -- percentage of royalties must equal 100 percent

Power Designer n Domains – Valid set of values for one or more attributes – Several attributes may have the same domain n usually not a 1:1 relationship between each attribute in the table and each domain – Examples BirthDate, HireDate, MeetingDate all share the DATE domain PurchasePrice, ListPrice share the MONEY domain

Power Designer n Domains – A fully developed data model includes domains for each of the model’s attributes – Functions of domains n determine allowable operations on attribute n determine which attributes can be compared with one another or used in combination with one another n determine allowable set of values for an attribute n help determine sizes and formats for corresponding database fields

Power Designer n Domains – Apply a data type to each domain; a data type can be used by more than one domain – Edit the data type for the domain to adjust the length and precision if necessary – When you assign a domain to an attribute, the attribute inherits the characteristics of that domain – Changes to a domain will be updated for all the attributes in that domain

Power Designer n Applying business rules – Apply to the level at which the rule most relates n if the rule affects an attribute, apply at the attribute level n if the rule affects an entity, apply at the entity level – Each business rule should be applied to an object in the data model (attributes, entities, relationships) – Applying the rules is a reminder to the designer of the conditions attached to an object

Power Designer n Applying check parameters – More general check parameters can be added at the domain level; usually added at the attribute level – For any field with a set of values or yes/no fields n LIST the values n DESCRIBE the values n examples Welfare (Y/N) Y -- On welfare; N -- Not on welfare Status (O,C,P) O -- Case is open; C -- Case closed; P -- Case pending

Power Designer n Views – Equivalent to a recordset returned by a query – All task screens and all reports should be based on information from n a subset of a table n subsets of more than one table – Remove fields that do not belong to the view – Edit the views using group by, where, and order by tabs