Bài giảng Romney_ais13 - Chapter 18: Implementing an REA Model in a Relational Database

Implementing an REA Model in a Relational DatabaseChapter 1818-1Learning ObjectivesIntegrate separate REA diagrams for individual business cycles into a single, comprehensive organization-wide REA diagram.Build a set of tables to implement an REA model of an AIS in a relational database.Explain how to write queries to retrieve information from an AIS relational database built according to the REA data model.18-2Combining REA DiagramsIndividual REA diagrams can be combined to form an integrated REA diagram by:Merging redundant resource entities (e.g., inventory is acquired in expenditure cycle and reduced in the sales cycle)Merging redundant event entities (e.g., disburse cash event appears in the expenditure cycle and the payroll cycle)18-3Integrated REA Diagram RulesEvery event must be linked to at least one resource.Every event must be linked to two agents who participate in that event.Every event that involves the disposition of a resource must be linked to an event that involves the acquisition of a resource (give-get exchange).Every resource must be linked to at least one event that increments that resource and to at least one event that decrements that resource.If event A can be linked to more than one other event, but cannot be linked simultaneously to all of those other events, then the REA diagram should show that event A is linked to a minimum of 0 of each of the other events.If an event can be linked to any one of a set of agents, then the ERA diagram should show that event is linked to a minimum of 0 of each of those agents.18-4Using an REA Diagram to Build a Relational DatabaseCreate tables for each distinct entity and M:N relationshipAssign attributes to each tableIdentify primary keysConcatenated keys for M:N relationship tableUse foreign keys to implement 1:1 and 1:N relationships18-5Deriving Accounting Information from REA DiagramJournalsInformation contained in event tablesLedgersInformation contained in resource tables (increment and decrements of events)Financial statementsInformation contained in resources and events using a set of queries Management reportsFinancial and nonfinancial information18-6Key TermConcatenated keys18-7