Information Systems and Databases Flashcards
Attribute
A defined property (or characteristic) of an entity in a database. Eg Entity = customer, attribute = name, address (ie fieldname)
Centralised database
A centralised database has all its data residing in one place
Composite key
A combination of two or more fields used to identify a record in the database.
Database
An organised collection of related data, stored in a way that meaningful information can be extracted.
Data dictionary
A list of field names containing information about how the data in each field is to be constructed
Data independence
The property of a DMA that allows you to change the schema at one level without requiring a change at the next level.
Data integrity
The accuracy, reliability and consistency of data. A well-designed database will enforce data integrity. An example: A use could accidentally try to enter a phone number in a date field.
Data mining
An analysis process that discovers new unintended relationships amongst data.
Data quality
Identifies how reliable and effective the data is in database; involves the accuracy of the data
Data redundancy
Repeated data in a database.
Data security
The process of protecting data from destructive forces and unwanted actions of unauthorised users
Data validation
The process of checking the validity of data at the data entry stage
Data warehouse
Electronic storage of a large amount of information, used as a method for collecting data from a range of sources. Used to provide meaningful business insights through mining of the data.
DBMS
Database Management System is software designed to define, manipulate, retrieve and manage data.
Distributed database
A database that consists of two or more file located at different sites on a computer network
Entity
A specific thing about which a system (ie database) collects. An entity is represented as a table in a database, eg customer, car, book
First normal form
Each table cell should contain a single value and each record should be unique
Flat file system
A stand- alone table of data
Foreign key
The primary key of another table, linked by a relationship, that must appear in all tables linked tables.
Form
Database object used for data entry. A form is the user interface for filling a table.
Hypermedia
Any media type, eg image, video, text, audio that allows interactivity, typically by touching a screen or clicking a mouse
Key
A field in database table used to sort data
Metadata
Information about data that provides a common ground for people working on a project at the same time
Network database
A database model that allows multiple records to be linked to the same owner file.
Normalising
The process of organising data in a database, eg creating tables and establishing relationships between those table according to rules designed to protect data and enforce data integrity and reduce data redundancy.
OLAP (Online Analytical Processing)
A software tool that provides analysis of data stored in a database and is used in data mining
OLTP (Online transaction processing)
Refers to a class of systems that facilitate and manage transaction-oriented applications, typically for data entry and retrieval transaction processing
Organising
Arranging data into tables within a database.
Primary key
An attribute that has a unique value, used to identify individual records, eg student number, ISBN of a book, rego plate of a car.
QBE (query by example)
A visual method of query where the search criteria is entered into an empty record and the records meeting this criterion will be displayed
Query language
A non-procedural language, designed to allow the database used to ask questions of the database
Redundancy
Repeated data in a database
Relational database
Multiple tables within a database that are linked by relationships and key fields
Relationship
The way in which entities (field names) are related to one another – the primary key is used to link entities
Schema
An organised plan of an entire database showing where the data is found (tables and fieldnames) and the logical relationships
Second Normal form
A relation is in second normal form if it is 1st normal form AND every non key attribute is fully functionally dependent on the primary key.
Single key
Any single attribute that uniquely identifies each record in a table
SQL
Structured Query Language is the standard language used to manage data in a database
Table
Displays information about an entity, eg customers, sales, products. A row in a table represents one record.
Validation
Check of the data to see if it is reasonable and lies within a predefined set of values
Verification
Check of the data source to see if it is correct
