Introduction to Databases in Business Information Systems

Database

structured collection of related data stored on a computer medium

DBMS

software used for creation of databases, insertion, storage, retrieval, update, and deletion of the data in the database, and maintenance of databases

Front-End Applications

provide a mechanism for easy interaction between the users and the DBMS

Indirect interaction

user communicating with the database through front-end applications that are communicating with the DBMS on user's behalf

Direct interaction

user communicating with the database directly through DBMS

Requirements collection, definition, and visualization

the first and most critical step in the development of the database, resulting in the requirements specifying which data the future database system will hold and in what fashion, and what the capabilities and functionalities of the database system will be

Conceptual database model

a visualization of requirements by using a conceptual data modeling technique such as entity-relationship (ER) modeling

Example of Indirect interaction

an ATM user interacting with the bank's database by using the screen on the ATM machine

Example of Direct interaction

User issuing commands in the language of DBMS (typically SQL)

Database Modeling

Creation of an implementable database model

Logical Database Model

Preferred model for corporate databases, typically relational.

Relational Database Model

A structured database model using tables and relationships.

Database Implementation

Using DBMS to create an actual database.

Relational DBMS (RDBMS)

Software for implementing relational database models.

Primary Key

Unique identifier for a database table record.

Foreign Key

Field linking to a primary key in another table.

Database Deployment

Releasing the database system for business use.

Data Entry Form

Interface component for inputting data into databases.

Database Use

Operations like insertion, modification, and retrieval.

ER Diagram (ERD)

Graphical representation of database requirements.

Entities

Constructs representing tracked database items.

Entity Instances

Occurrences of a specific entity in the database.

Database Administration

Activities supporting database end users.

Database Maintenance

Ensuring database functionality and security.

Navigation Mechanism

System for accessing different application interfaces.

Attributes

Characteristics that describe an entity's details.

Unique Attribute

Attribute with distinct values for each instance.

Relationship

Connection showing how entities relate in ER modeling.

Cardinality Constraints

Limits on how many instances relate between entities.

Maximum Cardinality

Defines upper limits of entity associations.

Minimum Cardinality

Defines lower limits of entity participation.

Relationship Instances

Occurrences of a relationship between entity instances.

Relational Schema

Visual representation of a relational database structure.

Relation

Table in a relational database containing rows and columns; the main construct in the relational database model.

Column

Each must have a name, and within one table, each name must be unique.

Row

Within one table, each must be unique.

Single valued

Within each row, each value in each column must be single valued; multiple values of the content represented by the column are not allowed.

Same domain

All values in each column must be from the same predefined domain.

Relational database

Collection of related relations within which each relation has a unique name.

1:M relationship mapping

The relation mapped from the entity on the M side of the 1:M relationship has a foreign key that corresponds to the primary key of the relation mapped from the 1 side.

M:N relationship mapping

In addition to the two relations representing the two entities involved in the M:N relationship, another relation is created to represent the M:N relationship itself.

Composite primary key

The two foreign keys in the new relation formed from an M:N relationship create a composite primary key.

Entity integrity constraint

In a relational table, no primary key column can have null (empty) values.

Referential integrity constraint

In each row of a relation containing a foreign key, the value of the foreign key either matches one of the values in the primary key column of the referred relation or is null.

Database front-end

Provides access to the database for indirect use.

Form

Enables data input and retrieval for end users; provides an interface into a database relation or query.

Report

Presents the data and calculations on the data from one or more tables from the database in a formatted way.