+ Information Systems and Databases 2.2 Organisation

+ Organisational Methods Organising is the process of arranging, representing and formatting data. Computer based databases have several advantages over non- computer based databases: Easily edited. Large storage. Fast retrieval. Display options.

+ Flat File Databases A Flat-file database organises data into a single table and is suitable for many small applications. They are divided into: File is a block of data. Record is a collection of facts about a specific entry in a database. Field is a specific category in a database. Character is the smallest unit of data used.

+ Flat File Databases…Cont. Keys are fields that are used to sort and retrieve information. Single Key is a field in which each item of data is unique. Composite Key is made by joining two or more fields together. Primary Key is a single key that must have a value. Secondary Key contains items of data.

+ Relational Databases A Relational Database organises data using a series of related tables. Relationships are built between the tables to provide a flexible way of manipulating and combining data.

+ Schema A Schema is the data definition for a database. It is an organised plan of the entire database showing how and where the data is found, descriptions of the data, and the data’s logical relationships. In a relational database, the schema defines the entities, attributes and relationships.

+ Schema…Cont. Entity: Is a specific thing about which information is collected and stored. Attribute: Is a defined property of an entity. Relationship: Is the way entities are related to each other. One to one. One to many Many to many. Foreign Key: is an attribute of a table that is a primary key of another table.

+ Tables & Forms Information about an entity is displayed in a table. A Table is the organisation of data into columns and rows. Data is viewed for different purposes using forms. A form is used to view, enter and change data in a table.

+ Data Modelling & Data Dictionaries Data modelling is the process of identifying entities, the relationships between those entities and attributes of those entities. It is used to develop a schema for a database. Data dictionaries are a comprehensive description of each field in a database. It contains Metadata, which is information about the data.

+ Schematic Diagrams Schematic Diagrams are graphical tools that help define that database and develop a schema. A common schematic diagram is the entity-relationship diagram. The ERD is a graphical method of identifying the entities and showing the relationships between them. It helps to determine what data should be included or excluded from the database.

+ Normalisation Normalisation is the process of organising data into tables so that the results of using the database are unambiguous and as intended. It is a refinement that helps reduce data redundancy. The degree of Normalisation is defined in terms of forms: First Norm Form (1NF). Domain Key Normal Form (DKNF).

+ Hypermedia & Hypertext Hypermedia is a combination of media whose locations are linked electronically to provide an easy way of navigating between them. Hypertext is a system that allows documents to be cross- linked in such a way that the user can move from one document to the next by simply clicking on a link.

+ Uniform Resource Locator A URL A (Uniform Resource Locator), is the address of a file or resource on the internet. In most cases the protocol will be It will consists of: Protocol. – Transfer method used Domain Name –Address of the specific computer File Path – Full path to the file to be retrieved.

+ Storyboard Storyboard is a series of frames, each representing a different action or screen image. It is a tool used to organise hypermedia. There are four storyboard types: Linear. Hierarchical. Non-linear. Combination.

+ HTML Web pages are created using HTML (Hypertext Markup Language). An HTML editor is software that specialises in writing HTML code.