Grade 11 Computer Science

Relational Databases  Using the link below, answer questions in your notebooks  Look at Kites.accdb database to refresh your memory Link  ict.com/gcse_computing/ocr/databases/relational/miniweb /index.htm ict.com/gcse_computing/ocr/databases/relational/miniweb /index.htm Quiz  ict.com/gcse_computing/ocr/databases/relational/quiz/eng arde_relationaldb.htm ict.com/gcse_computing/ocr/databases/relational/quiz/eng arde_relationaldb.htm

Database Questions 1. Give some advantages and disadvantages of a flat file database 2. Give a definition of a relational database 3. What is a primary key – give an example 4. What is a foreign key – give an example 5. Why must a database have ‘integrity’? 6. Why must a database must be up to date and accurate?

Database Answers Advantages of a flat file database are:  All records are stored in one place  Easy to understand  Simple sorting and filtering can be carried out  Can use a standard spreadsheet as simple database

Database Answers  Disadvantages of a flat file database are:  Potential Duplication – data can be repeated again and again which leads to problems  Records are not always unique – the doubling of the same data can be confusing  Harder to update  Inefficient – can be really slow to use as lots of data is repeated and maybe not needed  If you access to the one table, you have access to the whole database, which compromises security

Database Answers  A Relational Database is a two or more tables that are linked together that share data. The data is organized and systematic and is updated between tables so any changes made in one table, is shared and updated between all other tables.  A Primary Key is a unique identify that belongs to one table but can appear in other tables as well – ID number is a good choice for as every number is unique and individual  A Foreign Key is a Primary Key that appears in another table to link two tables together

Database Answers  Data Integrity means that data and information that is in your database is trustworthy. You are able to trust what it is telling you. This is because it is up to date because it is updated, it is accurate (no mistakes) and consistent so data in one table that appears in the another table is the same. For example, one person does not have their name spelt with two different spellings

Definitions  Query – a request made by the user to extract data from the database OR  A question asked of the database  Report - a printout of the query OR  Information from the Query in a different format  Integrity – all data is updated regularly including new information which is consistent and accurate

Web Design Revision  Answer Question 4 from Chapter 4 Web Design.pdf from page 36 in your copybooks  Write the question before each answer!  Information you need is from pages 33 to 36