Database

Database

A database is a collection of data or information which is held together in an organised or logical way.

Types of database:

•     Flat-file database: A flat file database is a type of database that stores data in a single table.

               Advantages: Easy to understand, Easy to implement, less skills are required to design.

               Disadvantages: Data inconsistency, slow for huge database, potential duplication

 

•    Relational database: is a collection of stored data that is organized into multiple tables linked to one another using key fields.

               Advantages: Data is only stored once, complex queries can be carried out, Easier to change data.

               Disadvantages: takes more time to be designed compared to flat-file, extra skills needed to link tables.

 

Field :

A field is a single piece of data about one person or one thing. Many fields make up a record. A field is usually a single column within a multi-column table. It is a single data item, such as Name, DOB …ect

 

Key fields (Primary key): The key field is a unique identifier for each record.

 

Record:

A record is all of the data about one person or one thing. A record is made up of one or more ‘fields’.

 

Table:

A table contains a set of records. Tables can be permanent or they can be created by a query for temporary use. You set up relationships between tables in order to create a relational database.

 

Query:

A query is a request for information from a database which matches a set of criteria.

You use queries all the time when you use a search engine such as Google. You type in the term that you want some information about and click ‘search’. The search engine looks through its database and displays a list of results which match the term that you used.

 

Report:

A report is a document (paper or electronic) that presents data in an easy-to-read, professional format.

Reports can be created within database applications such as Access. In this case the results of database queries are presented in an attractive format, with headings, fonts and colours designed to enhance understanding of the data.