Database Design P1, M1 & D1

Topics: SQL, Database, Relational model Pages: 5 (1351 words) Published: April 26, 2014
Assignment 1
Database design

Database is a place to store lots of data, imagine it as a giant virtual filling cabinet that can be organized in many ways. There’s software called (DBMS) which stands for database management system which allows the user to manage data in database such as; create, delete or update.

Entities

Entities are objects with significant mass and purpose, in database entities are tables. Every table contains many fields/attributes. The user must create a table before inputting any data. When creating a table you need to define a few things, data type, fields name & a description.

Fields Name

This is a column heading, this will display the title for the column etc first name, last name, address.

Data Type

This is the content of the data & the data type decides what content can be inputted & the file size.

Description

This is used to explain the content & shows a list of ‘limitations’ the user can change to get a more accurate reading etc. input mask.

Attributes
A characteristic, for example; a field has many attributes such as data like numbers or letters. Attributes can be used as a synonym for a “field”. In DOS systems, each files has an attribute, each file has many properties that shows if the file is “read only”, visible or encrypted. Queries

A query is use for searching some specific record. It allow user to set conditions and then search the record which match the conditions. User also is able to make the search mix up with other table and sort the order of the result.

Reports

A Report is a summary of record. Everything you plain to print should put inside. Its purpose is for user to view information quickly and easily so display the result simply and efficiently is the main point.

Forms

Form is used for collect and edits information and transfers them to table. It is similar to application forms that allow user to fill in or delete their data easily and it also able to let user design own user interface. User can insert as much control as they like to build the user interface beautifully. Relationships

Relationship types

Database relationships are very similar in that they're associations between tables. There are three types of relationships: One-to-one: both tables of the relationship have one field that matches up, for example; a married couple that both have a child that has no relation to the other partner. This rarely ever happens in a business organization One-to-many: one-to-many is where one table has none/one or many relations with the other table’s fields but the other table has only none/one field. For example, you have only one mother, but your mother may have several children. Many-to-many: Both tables have one/many relations to each other’s fields. Usually in this instance there are usually 3 tables.

Benefits
The benefits of having databases online are that it’s easier & quicker to do. The amount of paper saved & room is very beneficial. Its quicker & easier for the user to find important data in the database. The user can make forms to find & read information easier. The user can set rules to make the data input more accurate & legit. You can save the information on multiple storage units (hard drives) So if the information has been tampered with, there’s always a spare copy somewhere safe.

Task 2

Primary key

The primary key of a relational table uniquely identifies each attribute in the table. Primary keys could be a unique attribute such as “social security number” for a person or student etc. Primary keys may consist of a single attribute or multiple attributes in combination. Primary keys connect tables together in relationships

Referential integrity

there is a feature with databases called relational database management systems (RDBMS's) that prevents users or applications from entering inconsistent data. Most RDBMS's have referential integrity rules that you can apply when you create a...
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