1. Teacher Workshop
Database Design
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2. File-Based System Approach
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3. Database Approach
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4. Database
Shared collection of logically related data (and a description of this data)
designed to meet the information needs of an organization
System catalog (metadata) provides description of data to enable -
Program data independence
Logically related data comprises entities, attributes, and
relationships of an organization’s information
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5. Database Management System (DBMS)
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6. Database Approach Data definition language (DDL).
Permits specification of data types, structures and any data constraints.
All specifications are stored in the database.
Data manipulation language (DML).
General enquiry facility (query language) of the data.
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7. Components of DBMS Environment
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8. History of Database Systems
First-generation
Hierarchical and Network
Second generation
Relational
Third generation
Object-Relational
Object-Oriented
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9. ANSI-SPARC Three-Level Architecture
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10. Differences between Three Levels of ANSI-SPARC Architecture
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11. Data Independence and the ANSI-SPARC Three-Level Architecture
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12. Relational Data Model
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13. Network Data Model
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14. Hierarchical Data Model
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15. Instances of Branch and Staff Relations
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16. Alternative Terminology for Relational Model
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17. Mathematical Definition of Relation
Consider three sets D1, D2, D3 with Cartesian Product D1 ´ D2 ´ D3; e.g.
D1 = {1, 3} D2 = {2, 4} D3 = {5, 6}
D1 ´ D2 ´ D3 = {(1,2,5), (1,2,6), (1,4,5), (1,4,6), (3,2,5), (3,2,6), (3,4,5), (3,4,6)}
Any subset of these ordered triples is a relation.
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18. Relational Keys Primary Key Alternate Keys Foreign Key
Candidate key selected to identify tuples uniquely within relation.
Alternate Keys
Candidate keys that are not selected to be primary key.
Foreign Key
Attribute, or set of attributes, within one relation that matches candidate key of some (possibly same) relation.
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19. Integrity Constraints
Entity Integrity
In a base relation, no attribute of a primary key can be null.
Referential Integrity
If foreign key exists in a relation, either foreign key value must match a candidate key value of some tuple in its home relation or foreign key value must be wholly null.
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20. ER diagram of Branch Has Staff relationship

21. Attributes Attribute Attribute Domain
Property of an entity or a relationship type.
Attribute Domain
Set of allowable values for one or more attributes.

22. ER diagram of Staff and Branch entities and their attributes

23. Multiplicity of Staff Manages Branch (1:1) relationship

24. Semantic net of Staff Oversees PropertyForRent relationship type

25. Multiplicity of ternary Registers relationship

26. Summary of multiplicity constraints

27. Chapter 17 - Outline Build a logical data model (LDM) from a CDM
Validate LDM to ensure that
It accords the data requirements
It supports all the transactions
Merge local LDMs into a global model
Is the global LDM a true and accurate representation of the data requirements?

28. Objectives of SQL Consists of standard English words:
1) CREATE TABLE Staff(staffNo VARCHAR(5),
lName VARCHAR(15),
salary DECIMAL(7,2));
2) INSERT INTO Staff VALUES (‘SG16’, ‘Brown’, 8300);
3) SELECT staffNo, lName, salary
FROM Staff
WHERE salary > 10000; 28
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29. SELECT Statement FROM Specifies table(s) to be used.
WHERE Filters rows.
GROUP BY Forms groups of rows with same
column value.
HAVING Filters groups subject to some
condition.
SELECT Specifies which columns are to
appear in output.
ORDER BY Specifies the order of the output. 29
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30. Example 6.1 All Columns, All Rows
List full details of all staff.
SELECT staffNo, fName, lName, address,
position, sex, DOB, salary, branchNo
FROM Staff;
Can use * as an abbreviation for ‘all columns’:
SELECT * 30
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31. Example 6.1 All Columns, All Rows31
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32. Example 6.2 Specific Columns, All Rows
Produce a list of salaries for all staff, showing only staff number, first and last names, and salary.
SELECT staffNo, fName, lName, salary
FROM Staff; 32
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33. Example 6.2 Specific Columns, All Rows33
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34. Example 6.4 Calculated Fields
Produce list of monthly salaries for all staff, showing staff number, first/last name, and salary.
SELECT staffNo, fName, lName, salary/12
FROM Staff; 34
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35. Example 6.5 Comparison Search Condition
List all staff with a salary greater than 10,000.
SELECT staffNo, fName, lName, position, salary
FROM Staff
WHERE salary > 10000; 35
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36. Example 6.6 Compound Comparison Search Condition
List addresses of all branch offices in London or Glasgow.
SELECT *
FROM Branch
WHERE city = ‘London’ OR city = ‘Glasgow’; 36
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37. Example 6.7 Range Search Condition
List all staff with a salary between 20,000 and 30,000.
SELECT staffNo, fName, lName, position, salary
FROM Staff
WHERE salary BETWEEN AND 30000;
BETWEEN test includes the endpoints of range. 37
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38. Example 6.8 Set Membership
List all managers and supervisors.
SELECT staffNo, fName, lName, position
FROM Staff
WHERE position IN (‘Manager’, ‘Supervisor’); 38
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39. Example 6.9 Pattern Matching
Find all owners with the string ‘Glasgow’ in their address.
SELECT ownerNo, fName, lName, address, telNo
FROM PrivateOwner
WHERE address LIKE ‘%Glasgow%’; 39
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40. Example 6.10 NULL Search Condition
List details of all viewings on property PG4 where a comment has not been supplied.
There are 2 viewings for property PG4, one with and one without a comment.
Have to test for null explicitly using special keyword IS NULL:
SELECT clientNo, viewDate
FROM Viewing
WHERE propertyNo = ‘PG4’
AND comment IS NULL; 40
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41. Example 6.11 Single Column Ordering
List salaries for all staff, arranged in descending order of salary.
SELECT staffNo, fName, lName, salary
FROM Staff
ORDER BY salary DESC; 41
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42. SELECT Statement - Aggregates
ISO standard defines five aggregate functions:
COUNT returns number of values in specified column.
SUM returns sum of values in specified column.
AVG returns average of values in specified column.
MIN returns smallest value in specified column.
MAX returns largest value in specified column. 42
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43. Example 6.16 Use of MIN, MAX, AVG
Find minimum, maximum, and average staff salary.
SELECT MIN(salary) AS myMin,
MAX(salary) AS myMax,
AVG(salary) AS myAvg
FROM Staff;
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44. Example Use of GROUP BY
Find number of staff in each branch and their total salaries.
SELECT branchNo,
COUNT(staffNo) AS myCount,
SUM(salary) AS mySum
FROM Staff
GROUP BY branchNo
ORDER BY branchNo; 44
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45. Example 6.19 Subquery with Equality
List staff who work in branch at ‘163 Main St’.
SELECT staffNo, fName, lName, position
FROM Staff
WHERE branchNo =
(SELECT branchNo
FROM Branch
WHERE street = ‘163 Main St’); 45
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46. Example 6.21 Nested subquery: use of IN
List properties handled by staff at ‘163 Main St’.
SELECT propertyNo, street, city, postcode, type, rooms, rent
FROM PropertyForRent
WHERE staffNo IN
(SELECT staffNo
FROM Staff
WHERE branchNo =
(SELECT branchNo
FROM Branch
WHERE street = ‘163 Main St’)); 46
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47. Example Simple Join
List names of all clients who have viewed a property along with any comment supplied.
SELECT c.clientNo, fName, lName,
propertyNo, comment
FROM Client c, Viewing v
WHERE c.clientNo = v.clientNo; 47
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48. Example 6.26 Three Table Join
For each branch, list staff who manage properties, including city in which branch is located and properties they manage.
SELECT b.branchNo, b.city, s.staffNo, fName, lName,
propertyNo
FROM Branch b, Staff s, PropertyForRent p
WHERE b.branchNo = s.branchNo
AND s.staffNo = p.staffNo
ORDER BY b.branchNo, s.staffNo, propertyNo; 48
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49. Example 6.26 Three Table Join
Alternative formulation for FROM and WHERE:
FROM (Branch b JOIN Staff s USING branchNo)
AS bs JOIN PropertyForRent p USING staffNo 49
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50. Example 6.35 INSERT … VALUES
Insert a new row into Staff table supplying data for all columns.
INSERT INTO Staff
VALUES (‘SG16’, ‘Alan’, ‘Brown’, ‘Assistant’, ‘M’, Date‘ ’, 8300, ‘B003’); 50
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51. Example 6.38/39 UPDATE All Rows
Give all staff a 3% pay increase.
UPDATE Staff
SET salary = salary*1.03;
Give all Managers a 5% pay increase.
SET salary = salary*1.05
WHERE position = ‘Manager’; 51
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52. Example 6.41/42 DELETE Specific Rows
Delete all viewings that relate to property PG4.
DELETE FROM Viewing
WHERE propertyNo = ‘PG4’;
Delete all records from the Viewing table.
DELETE FROM Viewing; 52
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