Accounting Systems Chapter 4 Exam Prep

What are the two Approaches of Database Design?

1. Normalization • An assumption that everything initially stored in one large table 2. Semantic Data Modelling • An alternative way to design well-structured relational databases • Database designer uses knowledge of (i) how business processes typically work and (ii) information needs associated with transaction processing to draw a graphical picture of what to be included in the database • The resulting figure directly used to create relational tables

What is a DBMS?

A database management system (DBMS) acts as an interface between the database (data in files) and the various application programs (softwares). Data is separate from the software so we need an interface to demonstrate the relationship between the database and application programs.

What is a Database System?

A database system is a combination of the database (different interrelated files that are centrally coordinated), the DBMS, and the application programs that access the database through the DBMS.

What are the two attributes of relational Databases?

Primary Key: the row in a table (related to one table) Foreign Key: Foreign key is a primary key in another table which are interrelated or connected and provide data about certain aspects

What is a Schema?

Schema is the logical structure of the database and has a lot of files that are interrelated and centrally recorded. It shows the relationships between the elements (files) in a database.

What is a relational Database?

This is abstract data model that represents the contents of a database in the form of a table. It represents the conceptual and external schema as if that "data view" was truly stored in one table. A relational database is a tabular analysis or representation of data. • Each row and column show some relationship of the data • Can be used to explain the value of assets e.g. 2001 value, 2002 value • Each row in a relation is called a tuple • Each column contains data about one attribute of an entity

Explain the logical view of data.

This is for users at the external level of the database and describes how the user or programmer conceptually organises and understands the data. For example, suppose a sales manager views all customer information as being stored in a table.

Explain the Physical View of Data.

This is for users at the internal level of the database and describes how data is physically arranged in the file and stored in the system (usually on the computer).

Why have a set of related tables?

• Because errors can occur • Data stored in one large table can be redundant due to: Update anomaly - When data is not correctly recorded due to multiple records with same data Insert anomaly - When unable to add a record to the database Delete anomaly - Removing a record also removes unintended data from the database

What are the Three Levels of Schemas?

• Conceptual Level Schemas Organization wide view of entire database (inventory, sales, cash, purchases are all important to know overall position from an organizational perspective) Lists all the data elements and shows their relationships • External Level Schemas Individual user view of a portion of database Each view is a sub-schema because they are small parts of the database • Internal Level Schemas A low level view of database Describes how data are actually stored and accessed (record layouts, definitions, addresses, and indexes)

What are the DBMS Languages?

• Data Definition Language (DDL) Builds the data dictionary Creates the database Describes logical views for each user Specifies record or field security constraints • Data Manipulation (changing the structure of data not fraud) Language (DML) Changes the content in the database updating, inserting, and deleting data • Data Query (more information needed with question in mind) Language (DQL) o Enables users to retrieve, sort, and displayer specific data from the database • A Report Writer A language that simplifies report creation

List some advantages of Database System

• Data Integration: A user can make use of the data because files are integrated. • Data Sharing: With authorized access someone can get data from the data files from one place with ease • Minimizing Data Redundancy and Data Inconsistency: Eliminates the same data being stored in multiple files, thus reducing inconsistency in multiple versions of the same data • Data Independence: Data is separate from the programs that access it. Changes can be made to the data without necessitating a change in the programs and vice versa • Cross-Functional Analysis: Relationships between data from various organization departments can be more easily combined • Reporting flexibility: reports can be revised early and generated as needed and the database can be easily browsed to research a problem or obtain detailed information underlying a summary report • Central management of data: Data management is more efficient because a database administrator is responsible for coordinating, controlling and managing data

Discuss how database systems will affect the future of accounting.

• Database systems may profoundly affect the fundamental nature of accounting. For instance, database systems may lead to the abandonment of the double-entry accounting model. • If the amounts associated with a transactions are entered into a database system correctly, then it is necessary to store them only once, not twice • Database systems also have the potential to significantly alter the nature of external reporting • Perhaps the most significant effect of database systems will be the way accounting information is used in decision making • Relational databases, however, provide query languages that are powerful and easy to use • Managers can concentrate solely on specifying what information they want • Databases are good but not enough • Database Helps accountant to process data and produce information • Basic or fundamental accounting knwoeldge and well as IT knowledge is required so accounting will not disappear. It knowledge is making accounting stronger

Explain how you design a Database System

• Develop a conceptual view of the entire database • The conceptual view illustrates the different files and relationships between the files • The data dictionary is a "blueprint" of the structure of the database and includes data elements, field types, programs that use the data elements, outputs, and so on.

Explain how you design a relational database?

• You need to draw a table with columns and rows then provide data • Need to think about the keys (if only one table then the rows will be primary key. If you have more than one table you need to think about foreign key)