1 Chapter 1 Introduction to Accounting Information Systems Chapter 5 Database Management Systems
Dec 28, 2015
1
Chapter 1
Introduction to Accounting Information
Systems
Chapter 5
Database
Management
Systems
Learning Objectives
• Understand techniques to model complex accounting phenomena in E-R diagram
• Develop E-R diagrams that model effective accounting database structures
• Recognize components of relational tables and keys to effective DB design
• Understand use of SQL to create relational tables during implementation
• Manipulate tables to extract data
3
Entities/Attributes
• Entity - object, event, or agent about which data are collected– Objects - Inventory, equipment, cash
– Events - Orders, sales, purchases
– Agents - Customers, employees, vendors
• Attribute - item of data that characterizes and entity or relationship
4
Attribute hierarchy for entity Client
5
Model representations for entities and attributes
6
Relationships
7
Constraints on data model relationships
EMPLOYEE WORKS_COMPLETEDWorks
EMPLOYEE WORKS_COMPLETEDWorks
a. Cardinality constraints
b. Participation constraints
1 N
(1,1) (0,N)
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Relational Databases
• Relation - collection of data representing multiple occurrences of an object, event, or agent.
• Tuples (rows) - set of data that describe an instance of the entity represented by a relation; like a record in traditional file structure.
• Attributes (columns) - items of data that characterize an object, event, or agent; like fields in traditional file structure.
9
Mapping E-R Diagram to Database
• Create separate relational table for each entity.
• Determine primary key for each relation. Must uniquely identify any row within table.
• Determine attributes for each entity.
• Implement relationships among entities. (Primary key in one table exists as attribute in every table (entity) where relationship specified in E-R.
• Determine attributes, if any, for relationship tables.
10
Hours
Name Contact Phone_noStreet_address City State Zip_codeClient_No.
Client_No.Employee_No. Date
CLIENT
WORK_COMPLETED
Employee_No. Soc_Sec_No Supervisor_No Billing_RatePay_RateName
EMPLOYEE
TRAINING_COMPLETED
Employee_No. Date Hours Train_code
RELEASE_TIME
Employee_No. Date Hours Vacation_Sick
Schema - billing & HR database
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Hours
Name Contact Phone_noStreet_address City State Zip_codeClient_No.
Client_No.Employee_No. Date
CLIENT
WORK_COMPLETED
Employee_No. Soc_Sec_No Supervisor_No Billing_RatePay_RateName
EMPLOYEE
TRAINING_COMPLETED
Employee_No. Date Hours Train_code
RELEASE_TIME
Employee_No. Date Hours Vacation_Sick
Referential constraints - relational schema
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13
SQL : Relational DB Query Language
• Used to
– define database systems
– query DB for information
– generate reports from DB
– access DB from within programs
• De facto standard DB language
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Constructing DBs using SQL
• Assign name to relation
• Assign names to attributes
• Specify data type for attributes
• Specify constraints, when appropriate, on the attributes.
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Other SQL functions
• Update DB -– add tuple using INSERT– remove tuple using DELETE– change attribute value using UPDATE
• Query DB using SELECT/WHERE
• Generate standard reports from DB– ad hoc (as necessary)– repetitive - might generate subschema view
Learning Objectives
• Understand techniques to model complex accounting phenomena in E-R diagram
• Develop E-R diagrams that model effective accounting database structures
• Recognize components of relational tables and keys to effective DB design
• Understand use of SQL to create relational tables during implementation
• Manipulate tables to extract data