TECHNOLOGY
Why is it important to understand the the concept of binary system?
It will help you to be a better programmer.
2 different fractions used in ancient Egyptian scribe.
Egyptian Fraction and Horus-Eye Fraction
What is prosody?
The study and use of the basic rhythmic structure of a verse or lines in verses of poetry.
Who developed the binary system that we use today and when?
Gottfried Leibniz in 1679
Who introduced the Boolean algebra and when?
George Boole (British) in 1854
The main logic operations of Boolean Algebra
1. Congugation (AND) ^
2. Disjunction (OR) V
3. Negation (NOT) ]
Boolean logic operates as
Logic gates
What computer is the first freely programmable computer in the world which used Boolean Logic and Binary Floating Point Numbers.
Z1 Computer
Who designed the Z1 Computer?
Konrad Zuse (German civil engineer, inventor and computer poineer. He designed it from 1936 to 1937 and finished at 1938.
What is computer?
An electronic device for storing and processing data.
What is binary?
A numeric system that only uses 2 digits - 0 and 1
Computers use what systems to store data and perform calculations?
Binary System
Pictures and characters are represented in the computers memory as Binary Information.
This information is referred to as
"Computers language."
Byte is enough storage location for a
letter, an alphabet, a character or a small number.
In the digital world, the transistors act as
tiny binary switches that control the flow of electricity.
What are transistors?
Fundamental building block of computer circuitry.
Closed switch represented as ___& open switch represented as ___.
1 & 0 respectively
What system do computers used to represent data in switches?
Binary Coding System
What numbers are employed by this following numbers?
Binary number system
Decimal number system
Hexagonal number system
Octal number system
2
10
16
8
What is octale number system?
Digital numbers system that operates at a base of 8.
What is the importance of using octale number system?
To reduce the bulkiness of the binary information.
Advantages and disadvantages of octale.
Advantages
1. Size of binary string in octale representation is small.
2. Chances of errors are minimized.
3. Bits can be easily converted when needed.
Disadvantages
1. Data in octale form must always be converted to binary form thus there is an additional converting operation needed by the digital circuits.
What is hexadecimal number system?
The number system that operates at the base of 16.
10 digits are numbers while 6 are extra symbols.
(0123456789ABCDEF)
Hexadecimal numbers are usually indicated by
Ox prefix /h suffix
In a computer jargon, four bits is called
A nibble
Most computers used the hexadecimal system to represent most error codes like
STOP codes and Blue Screen of Death
Why do programmers use hexadecimal system?
Because their values are shorter.
Hexadecimals are used in
Hyper-Text Markup Language color codes to represent specific colors.
3 types of DBMS users. Name them
1.Administrators
2. Designers
3. End users
Name the 3-tier Architecture
1. Presentation Tier (Client Tier)
2. Application Tier (Logic Tier)
3.Database Tier
What is the 3-tier architecture?
The way of organizing applications into 3 layers. Each work independently to improve maintenance, scalability, and security.
What is Entity-Relationship Model and what is its purpose?
The graphical representation of a database's structure. It is used to plan the logical structure of databases before they are technically implemented.
ER Model is based on
Entities and their attributes
Relationships among entities
What is relationship?
The logical association among entities.
State all the mapping cardinalities.
a) one to one
b) one to many
c) many to one
d) many to many
What is Relational Model?
A way of organizing tables (called relation) with rows and columns.
What is Database Schema?
Is the skeleton structure that represents the logical view of the entire database.
Name the 2 broad categories of Database Schema.
1. Physical Database Schema
2. Logical Database Schema
What is physical database schema?
The layout of how data is stored in the hardware.
What is Logical Database Schema?
A structured framework outlining how data is organized within a databse system, focusing on tables, views, columns and constrains witgout specifying the physical storage.
State the difference between database schema and database instance.
Database Schema is the skeleton of databade while database instance is a state of operational database with data at any given time.
What is Data independence?
The ability to change the structure of a data without affecting the applications that uses the data.
What is metadata?
Data about data
There are two types of data independence. Name them.
1. Logical Data Independence
2. Physical Data Independence
What is local data independence?
The ability to make changes to the logical structures of a database without alternation tothe application problems that access the data.
What is physical data independence?
The ability yo change the internal schema of a database without changing yhe local schema or the applications thst rely on it.
What are entities?
An object or thing in the real world with an independent existence.
What are attributes?
attributes are the properties of entity (ies)
Types of attributes
1. Simple attribute- cannot be divided into smaller parts.
2. Composite attribute- can be divided into smaller sub-parts.
3. Derived attribute- values derived from other attributes
4. Single-value attributes- single value for each entity.
5.Multi-value attribute- multiple values of a single entity.
What is key?
Collection of attributes that uniquely identifies an entity among entiry set.
What is relationship?
Association among entities.
What is mapping cardinalities?
The association of entities to another entinies through relationship.
Types of cardinality. Name them
@ 0-1
@ one-to-many
@ many-to one
@ many- to-many
Entities are represented by what shape?
Rectangles
What shape represent attributes?
Ellipse
Multivalued attributes are represented with
Double ellipse
Derived attributes are represented with
Dashed ellipse
Relationship are represented with
Diamnond-shaped box
What is a binary relationship?
A relationship where two entities are participating.
What is instance?
A single row of specific data.
What is cardinality?
Number of relationship between rows in one table with rows in other.
What is a participation constrain?
It defines how much involvement an entity must have in a relationship.
Name the two types of participation constrains.
1.Total participation
2. Partial participation
What is total participation?
Each entity is involved in the relationship and is represented with double lines.
What is partial participation?
Not all the entities are involved and is represented with single lines.
What is generalization?
The process of generalizing entities.
What is specialization?
Process of dividing a group of entitues into sub-groups based on their characteristics.
What is abstraction?
Hiding the complex details of how a data is stored and maintain and showing only the useful information to the user.
What are the characteristics of database management?
1. Real-world entity
2. Relation-based table
3. Isolation of data and application
4. Less redundancy
5. Consistency
6. Query language
7. ACID properties
8. Multiuser and Concurrent access
9. Multiple views
10. Security
What is the role of administrators in DBMS?
Maintain the DBMS and are responsible for maintaining the database.
What is the role of the designers in DBMS?
People who actually work on the designing part of the database.
What are the role of end users of DBMS?
They reap the results produced by the designers.