Databases are used to store data. Data can be entered into a database, and it can be retrieved from a database. Information is data which is organised into a more human readable format. There are two types of people concerned with databases. Those that design databases, and those that use databases. You will already have used database theory whenever you have made a table to store your results in science, maths or geography. The purpose of this unit is to level up your skills in order that you can create databases with multiple tables, and become a more proficient user.
Databases can be visualised as a series of related tables of information. Each table stores information about a type of entity. The rows of each table store records - information about a specific entity. The columns of each table store information about one aspect of each entity. There are four basic commands which a database can perform once it is designed.
Create - that is make a record
Retrieve - that is get information about a record
Update - That is take stored information and enter new information in the same record.
Delete - That is to remove the record from the database
Aims
This is an introduction to databases, and how they are used
By the end of this unit you will learn:
Level 3
(data) Understands difference between data and information
(data) knows why storing information in a flat file dataabse can improve storing and saving information
(data) can use filters and single criteria searches
Level 4
(data) performs searches using boolean and relational operators.
(data) analyses data and information.
Level 5
(data) knows that computers use binary to represent all information
(data) defines datatypes - (real and boolean)
(data) queries data on a flat database using SQL
Level 6
(data) distinguishes between data, and the storage strategy
(data) understands the use and need of an index key in a database.
Level 7
(data) understands boolean logic
(data) understands how and why data is typed in QBE and SQL
Activity 1
The planets are interesting features of our solar system which we can use to make a database for. We can use this database later to extract critical information to use later.
Learning aims:
Level 3 Data
Create and edit data in a flat file database
The planets
Our information about the planets comes from the following source http://www.bobthealien.co.uk/table.htm.
The first step in designing a database is to design a set of facts. a fact is a sentence that relates to a set of information.
Example
The planet with the name ___ has a mass of ___ kg.
The planet with the name ___ has a diameter of ___m.
The planet with the name ___ has a density of ___ kg/m3
Note that each of these "binary facts" goes with the same pattern. The entity with the unique property ___ has a property of ___
What is the entity in each of the examples?
What is the unique property in eack of the examples?
What are the properties in each of the three examples?
Write 4 more binary fact sentences from the tables provided.
When we talk about databases - we call these properities "fields". We call the field that is unique to each entity its "key"
The purpose of a key is to speed up searching for things.
In this activity you will prepare a flat file database. This is not too different to what you could achieve in Excel, and yes excell may be a better tool for what yuou achieve in this activity, but we will take this further in the next exercises.
Answer the questions, and resubmit into the moodle.
Upload your answers to the moodle.
Activity 4
Going further
Learning aims:
Level 6
(data) distinguishes between data, and the storage strategy
(data) understands the use and need of an index key in a database.
What about the moons?
So far we have used a simple flat database. A flat database is based on only one table. We can make much more use of our database if we use a relational structure. In this exercise we will expand our database by expanding it to encompas a second type of entity.
New entiry types require new tables. We are going to have to design a new table which relates to moons. This is very simmilar to the process we did for creating the table about planets except that we will be including one extra field which links our moon to the correct planet.
When we have done this we can do some cool things, We will make a new type of form, and report that deals with the moons to demonstrate some of these features.
What to hand in.
Please submit the following in a single word document
A set of binary facts related to the moons.
A conceptual schema diagram including the moons.
A schema
Screenshots of your database design tables
Screenshots of your forms and queries.
Activity 5
Database Creation Exercise
Learning aims:
Independant use of all learning aims.
Task
Pick one project brief, and create a database which resolves the problem stated.
Create a movie database which contains the details of the movies you have watched and the actors/actresses who atarred in them
Create a database of the courses available to you at the local colleges, make sure all the relavent details for each course are included.
Create a database for storing homework assignments in. Include all the relavent details.
You will need to hand in the following:
A set of binary facts related to the problem.
A conceptual schema diagram including the problem.
A schema
Screenshots of your database design tables
Screenshots of your forms and queries.
Activity 6
Extension Exercise
Learning aims:
Level 7
(data) understands boolean logic
(data) understands how and why data is typed in QBE and SQL