REA Model

• resources,events, agents
• business events, affect firm resources and involve agents who participate

Step 2 and 4 for REA Model

Identifying Entities

Create Entity Relationship Diagrams

Step one and Six of REA Model

Identify business and economic events

Converty ER Diagrams into database tools

Step Three and Five in REA Model

Identify Relationships among entities

Identify attributes of entities

Normalization

Ensuring attributes are in appropriate tablles and that the design of database promotes accurate and nonredundant storage of data.

First Normal Form

THIRD NORMAL FORM

NO TRANSITIVE DEPENDICIES

SECOND NORMAL FORM

IN 1ST NORMAL FORM AND ALL ATTRIBUTES IN EACH RECORD  DEPEND PRIMARILY ON RECORDS PRIMARY KEY

TRANSITIVE DEPENDICIES

SAME RECORD DOES NOT CONTAIN ANY DATA FIELDS WHERE DATA FIELD A DETERMINES DATA FIELD B

RESOURCES

THINGS OF ECONOMIC VALUE

BUSINESS EVENT

AFFECT IMPORTANT ASPECTS OF AN ORGANIZATION

.

ECONOMIC EVENTS

AFFECT AN ORGANIZATIONS FINANCIAL STATEMENTS

ONE-TO-MANY

CARDINALITY RULE THAT EXPLAINS AGENT EVENT RELATIONSHIPS

DATABASE

LARGE COLLECTION OF ORGANIZED DATA THAT CAN BE ACCESSED BY MULTIPLE USERS AND U SED BY MANY DIFFERENT COMPUTER APPLICATIONS

DBMS

DATABASE MANAGEMENT SYSTEMS

FIRST STEP IN DATA HIERARCHY

DATA FIELD

THIRD STEP IN DATA HIERARCHY

FILE

SECOND STEP IN DATA HIERARCHY

RECORD

FOURTH STEP IN DATA HIERARCHY

DATABASE

PRIMARY KEY

DATA FIELD IN EACH RECORD THAT IS A UNIQUE IDENTIFIER

FOREIGN KEY

ENABLE USERS TO REFERENCE ONE OR MORE RECORD IN OTHER TABLES

RECORD STRUCTURE

SPECIFIC DATA FIELDS IN EACH RECORD OF A DATABLE TABLE

DATA DICTIONARY

DESCRIBES THE DATA FIELDS IN EACH DATABASE RECORD

<DATA FILE ABOUT DATA ITSELF>

REFERS TO THE LOCKING MECHANISMS THAT DO NOT ALLOW MULTIPLE USERS TO ACCESS THE SAME RECORD AT THE SAME TIME

DATA INTEGRITY

CONTROLS DESIGNED BY DEVELOPERS TO TEST FOR DATA COMPLETENESS, CONFORMANCE TO DATA TYPE SPECIFIED FOR DATA FIELD, VALID CODE AND REASONABLE TEST