The document reviews database concepts like fields, attributes, data types, primary keys and validation rules. It provides examples of designing databases to store student information and sales data. It also discusses database objects like tables, queries, forms and reports. Entity-relationship diagrams are explained as a way to model relationships between entities like one-to-one, one-to-many and many-to-many. Examples are given of modeling relationships for students, forms, employees, projects and more.

1. Review of database basics

2. Fields Attributes ‘ atomic’ Data types Primary key Validation rules Input masks L: letter A-Z (required) ?: letter A-Z (optional) 0: number 0-9 (required) 9: number (optional) range (or limit) check, e.g. between 10 and 20, >10 list check, e.g. ‘a’ OR ‘b’ OR ‘c’ (better as a dropdown list) Design a database to store personal information of 6 th Form students

3. tables queries (select some data only) macros forms (on screen) reports (on paper) what the user can see add a new student see all students see all in Year 13 list of all students list of all in Year 13 ? Design a database to store personal information of 6 th Form students

4. Primary key? Starter £4.00 3 13 1125 £2.00 2 12 1125 £4.00 1 13 1124 £3.00 1 14 1123 £2.00 2 12 1123 £4.00 3 13 1122 £2.00 2 12 1122 price quantitySold stockNum orderNum

5. Database exercise

6. Project number Project name Employee number Employee name Rate category Hourly rate 1. consider single table Consider the Employees and Projects table on the webpage 2. assign primary key(s)? Project number Project name Employee number Employee name Rate category Hourly rate 5. spot another (less obvious) Employee number Employee name Rate category Hourly rate Project number Employee number 6. …and remove it Employee number Employee name Rate category Project number Employee number Project number Project name Rate category Hourly rate 3. spot repeated groups of data… Project number Project name Employee number Employee name Rate category Hourly rate 4. …and remove them Employee number Employee name Rate category Hourly rate Project number Employee number Project number Project name

7. Entity-relationship diagrams

8. Entity-relationship diagrams

10. form student ONE form(s) contains ONE student(s) MANY MANY event world record ONE event(s) has ONE world record(s) MANY MANY employee project ONE employee(s) can work on ONE project(s) MANY MANY ( ) ( ) ( ) ( ) ( ) ( )

11. event world record ONE event(s) has ONE world record(s) MANY MANY ( ) ( ) event world record might as well merge into the one table (nothing to be gained from having two) a ONE-to-ONE relationship

12. form student ONE form(s) contains ONE student(s) MANY MANY ( ) ( ) This is what you are after It makes your database more efficient a ONE-to-MANY relationship form student

13. employee project ONE employee(s) can work on ONE project(s) MANY MANY ( ) ( ) Impossible to do in your database! Needs to be resolved… a MANY-to-MANY relationship employee project employee project employee_project Use a ‘link’ table between them  

17. publisher book author film actor director student course customer product stock item supplier staff employee project Others to practice with

18. Project number Project name Employee number Employee name Rate category Hourly rate 1. consider single table Consider the Employees and Projects table on the webpage 2. assign primary key(s)? Project number Project name Employee number Employee name Rate category Hourly rate 5. spot another (less obvious) Employee number Employee name Rate category Hourly rate Project number Employee number 6. …and remove it Employee number Employee name Rate category Project number Employee number Project number Project name Rate category Hourly rate 3. spot repeated groups of data… Project number Project name Employee number Employee name Rate category Hourly rate 4. …and remove them Employee number Employee name Rate category Hourly rate Project number Employee number Project number Project name

19. Impossible to do in your database! Needs to be ‘resolved’… a MANY-to-MANY relationship employee project 1. first ERD Consider the Employees and Projects table again: employee project employee_project Use a ‘link’ table between them 2. second ERD employee project employee_project Employee number Employee name Rate category Hourly rate Employee number Project number Project number Project name 3. consider attributes 4. spot repeated group of data and remove employee project employee_project Employee number Employee name Rate category Employee number Project number Project number Project name rate Rate category Hourly rate