1. Programming Constructs
Andrew Csizmadia
Monday 5th December 2016

2. Prerequisites for Learners
For learners to be successful in using and engaging with programming theory, they will need to be:
Familiar with fundamental programming constructs: selection, sequence and iteration
Able to successfully read pseudocode
Able to successfully write pseudocode
Able to successfully debug pseudocode
Able to use successfully use Computational Thinking concepts

3. arrays

4. Simple vs Structured Data Types
Simple data type => data element contains a single value
Structured data type => a data element contains a collection of data values
x : 15
avg : 84.35
ch : ‘A’
scores :
name : ‘C’ ‘L’ ‘Y’ ‘D’ ‘E’

5. Big Idea - Array
A variable can have a value that combines many values.
You can:
Extract one value
Update part of the variable
This idea is essential for representing complex data in programs:
a song,
an image
a map

6. Big Idea - Arrays An array is a static data structure, Can: Cannot:
i.e. its size is fixed
Can:
Select (i.e. index) one entry
Update one entry
Cannot:
Add an extra entry to the start or end
Insert/remove item from the middle

7. Arrays Arrays are Structured Static Data Types
They have a means of accessing individual components using an index
Values can be retrieved from and stored in the structure
Structure given a single name
Votes 12 34 23 43 21 35 22
Index 1 2 3 4 5 6
Individual elements accessed by index (integer Value) indicating relative position in collection

8. Arrays (1D) - Overview Structure - List
Techniques - Create, Initialise, Search, Sort, Find Item, Reverse
Implementation:
Python (List)
Application(s):
Searching (Linear, Binary)
Sorting (i.e. Quicksort)

9. Two-Dimensional (2D) Arrays
Arrays may have multiple dimensions.
Two-dimensional arrays can be visualized as tables with rows and columns.
A two dimensional array is really an “array of arrays” where each element of a one-dimensional array contains another array.

10. Declaring a 2D Array
Here is how you would declare a two-dimensional array chessboard with 8 rows and 8 columns:
chessboard = table[8] [8]
chessboard = table[8, 8]
chessboard[8][8]
chessboard[8, 8] 1 2 3 4 5 6 7
Rows 1 2 3 4 5 6 7
Columns

11. Which Way to label?
Which way should be label/reference a two dimensional array? 1 2 3 4 5 6 7 7 6 5 4 3 2 1
Rows
Rows OR 1 2 3 4 5 6 7 1 2 3 4 5 6 7
Columns
Columns
Which square is Chessboard [4, 4] is referring to?

12. Conceptualizing Two-D Arrays
int [ ] [ ] table = new int [4][5];
The variable table references an array of four elements.
Each of these elements in turn references an array of five integers … table is really an array of arrays.

13. Conceptualizing Two-D Arrays
More specifically, table is an array of four memory locations and in each memory location of that array there is an array that has five memory locations. So table[0] refers to the first row of the 2D array and table[1] refers to the second row, table[2] refers to the third row and table[3] refers to the fourth row.
Using the code table[2][3] allows us to work with the memory location in the third row and fourth column named row 2 column 3.

14. Conceptualizing Two-D Arrays
A table of numbers, for instance, can be implemented as a two-dimensional array. The figure shows a two-dimensional array with four rows and five columns that contains some numbers.

15. Accessing an Element of a Two-D Array
Suppose we name the array table; then to indicate an element in table, we specify its row and column position, remembering that index values start at 0:
x = table[2][3]; // Set x to 23, the value in (row 2, column 3)

16. Arrays (2D) - Overview Structure - Table
Techniques - Create, Initialise, Search, Sort, Find Item, Reverse
Implementation:
Python (List of lists)
Application(s):
Storing a table of data
Image representation
Game simulation
Modelling relationships, networks and maps with graphs
Building blocks for other data structures, i.e. trees

17. records

18. Records In computer science, a record :
In computer science, a record :
contains a collection of data for each entity
usually recorded as a row in a table

19. SQL (STRUCTURED Query Language)

20. SQL (Structured Query Language)
SQL stands for Structured Query Language.
It is the most commonly used relational database language today.
SQL works with a variety of different fourth-generation (4GL) programming languages, such as Visual Basic, Python.

21. SQL is used for: Data Manipulation Data Definition Data Administration
All are expressed as an SQL statement or command.

22. SQL
SQL Requirements
SQL Must be embedded in a programming language, or used with a 4GL like VB or Python
SQL is a free form language so there is no limit to the number of words per line or fixed line break.
Syntax statements, words or phrases are always in lower case; keywords are in uppercase.
Not all versions are case sensitive!

23. SQL and Relational Database
A Fully Relational Database Management System must:
Represent all info in database as tables
Keep logical representation of data independent from its physical storage characteristics
Use one high-level language for structuring, querying, and changing info in the database
Support the main relational operations
Support alternate ways of looking at data in tables
Provide a method for differentiating between unknown values and nulls (zero or blank)
Support Mechanisms for integrity, authorization, transactions, and recovery

24. Design SQL represents all information in the form of tables
Supports three relational operations: selection, projection, and join.
These are for specifying exactly what data you want to display or use
SQL is used for data manipulation, definition and administration .

25. Table Design Name Address Jane Doe 123 Main Street John Smith
SQL
Table Design
Columns describe one characteristic of the entity
Rows describe the Occurrence of an Entity
Name
Address
Jane Doe
123 Main Street
John Smith
456 Second Street
Mary Poe
789 Third Ave

26. Data Retrieval (Queries)
Queries search the database, fetch info, and display it. This is done using the keyword
SELECT
SELECT * FROM publishers
pub_id
pub_name
address
state
0736
New Age Books
1 1st Street MA
0987
Binnet & Hardley
2 2nd Street DC
1120
Algodata Infosys
3 3rd Street CA
The * Operator asks for every column in the table.

27. Data Retrieval (Queries)
Queries can be more specific with a few more lines
SELECT * from publishers where state = ‘CA’
pub_id
pub_name
address
state
0736
New Age Books
1 1st Street MA
0987
Binnet & Hardley
2 2nd Street DC
1120
Algodata Infosys
3 3rd Street CA
Only publishers in CA are displayed

28. Data Input Putting data into a table is accomplished using the keyword
INSERT
Variable
INSERT INTO publishers VALUES (‘0010’, ‘pragmatics’, ‘4 4th Ln’, ‘chicago’, ‘il’)
Keyword
pub_id
pub_name
address
state
0736
New Age Books
1 1st Street MA
0987
Binnet & Hardley
2 2nd Street DC
1120
Algodata Infosys
3 3rd Street CA
pub_id
pub_name
address
state
0010
Pragmatics
4 4th Ln IL
0736
New Age Books
1 1st Street MA
0987
Binnet & Hardley
2 2nd Street DC
1120
Algodata Infosys
3 3rd Street CA
Table is updated with new information

29. pub_id
pub_name
address
state
0010
Pragmatics
4 4th Ln IL
0736
New Age Books
1 1st Street MA
0987
Binnet & Hardley
2 2nd Street DC
1120
Algodata Infosys
3 3rd Street CA
Types of Tables
There are two types of tables which make up a relational database in SQL
User Tables: contain information that is the database management system
System Tables: contain the database description, kept up to date by DBMS itself
Relation
Table
Tuple
Row
Attribute
Column

30. Using SQL
SQL statements can be embedded into a program (cgi or perl script, Visual Basic, MS Access) OR
SQL statements can be entered directly at the command prompt of the SQL software being used (such as mySQL)
SQL Database

31. Using SQL CREATE DATABASE database_name USE database_name
To begin, you must first CREATE a database using the following SQL statement:
CREATE DATABASE database_name
Depending on the version of SQL being used the following statement is needed to begin using the database:
USE database_name

32. Using SQL
To create a table in the current database, use the CREATE TABLE keyword
CREATE TABLE authors (auth_id int(9) not null, auth_name char(40) not null)
auth_id
auth_name
(9 digit int)
(40 char string)

33. Using SQL
To insert data in the current table, use the keyword INSERT INTO
INSERT INTO authors values(‘ ’, ‘John Smith’)
Then issue the statement
SELECT * FROM authors
auth_id
auth_name
John Smith

34. Using SQL auth_id auth_name auth_city auth_state 123456789 Jane Doe
If you only want to display the author’s name and city from the following table:
auth_id
auth_name
auth_city
auth_state
Jane Doe
Dearborn MI
John Smith
Taylor
SELECT auth_name, auth_city FROM publishers
auth_name
auth_city
Jane Doe
Dearborn
John Smith
Taylor

35. Using SQL auth_id auth_name auth_city auth_state 123456789 Jane Doe
To delete data from a table, use the DELETE statement:
DELETE from authors WHERE auth_name=‘John Smith’
auth_id
auth_name
auth_city
auth_state
Jane Doe
Dearborn MI
John Smith
Taylor

36. Using SQL auth_id auth_name auth_city auth_state 123456789 Jane Doe
To Update information in a database use the UPDATE keyword
UPDATE authors SET auth_name=‘hello’
auth_id
auth_name
auth_city
auth_state
Jane Doe
Dearborn MI
John Smith
Taylor
Hello
Hello
Sets all auth_name fields to hello

37. Using SQL auth_id auth_name auth_city auth_state 123456789 Jane Doe
To change a table in a database use ALTER TABLE. ADD adds a characteristic.
ALTER TABLE authors ADD birth_date datetime null
Type
Initializer
auth_id
auth_name
auth_city
auth_state
Jane Doe
Dearborn MI
John Smith
Taylor
birth_date .
ADD puts a new column in the table called birth_date

38. Using SQL auth_id auth_name auth_city auth_state 123456789 Jane Doe
To delete a column or row, use the keyword DROP
ALTER TABLE authors DROP birth_date
auth_id
auth_name
auth_city
auth_state
Jane Doe
Dearborn MI
John Smith
Taylor
auth_state .
DROP removed the birth_date characteristic from the table

39. Using SQL auth_id auth_name auth_city auth_state 123456789 Jane Doe
The DROP statement is also used to delete an entire database.
DROP DATABASE authors
auth_id
auth_name
auth_city
auth_state
Jane Doe
Dearborn MI
John Smith
Taylor
DROP removed the database and returned the memory to system

40. Activity: w3Schools’ SQL Tutorial
Work through w3Schools’ SQL tutorial
Challenge
SQL
Learning Mat
SQL Workbook
SC : Creating and Manipulating SQL Databases

41. Activity: SQL with Khan Academy
Work through Creating SQL databases with Khan Academy
Challenge
SQL
Learning Mat
SQL Workbook
SC : Creating and Manipulating SQL Databases

42. Activity: SQL with Access
Explore using SQL with Northwest Trader
Challenge
SQL
Learning Mat
SQL Workbook
SC : Using SQL with Access

43. SQL Summary
SQL is a versatile language that can integrate with numerous 4GL languages and applications
SQL simplifies data manipulation by reducing the amount of code required.
More reliable than creating a database using files with linked-list implementation
Determine the best close for your audience and your presentation. Close with a summary; offer options; recommend a strategy; suggest a plan; set a goal. Keep your focus throughout your presentation, and you will more likely achieve your purpose.

44. Design - Subroutines
Subroutines are used to allows us to breakdown (decompose) a complex task into a set of solvable tasks in order to produce a solution to the original task.
Subroutine may be :
a function which returns value(s)
a procedure which does not return a value

45. Design - Subroutines
Using subroutines allows the designer or programmer to focus on one task as a time.
Advantages
Modular approach
Efficient – only need to replace subroutine if change is required.

46. Subroutines and Parameters
move (playerToPlay)
Value(s) can be passed to a subroutine via parameter(s) to be used in that subroutine
Aim – create a generalised subroutine, which perform the same task using different values. (Efficient design, Elegant design).
currentPlayer = playerOne
move(currentPlayer)
currentPlayer = playerTwo ① ② ③ ④

47. Task : Tic-Tac-Toe Design
Identify the subroutines that would be used to design a program to play tic-tac-toe (O-X-O)
Challenge(s)
Identify the subroutines which will need parameter(s) passed to them
Identify the subroutines (functions) which will return parameter(s)
SC : Identify the subroutines requited to play Tic-Tac-Toc (O-X-O)

48. Any questions?
Refreshments in diner 4pm