1. بسم الله الرحمن الرحيم

2. Welcome Welcome to حسب304 An Introduction to databases.
We hope you will enjoy it.

3. Information about course
إسم المقرر : مبادئ قواعد البيانات An Introduction to databases
رمز المقرر :حسب304

4. Database course - People
المحاضر: أ.ايمان محمد الحسن.
Office hours: Tuesday 10-2.
مساعدى التدريس:

5. Cont.
مدة الدراسة :
محاضرة واحدة أسبوعيا لمدة اربعة عشر أسبوعا ، مدة المحاضرة ساعتان .
تقييم المقرر:
60% الامتحان النهائي
20% الامتحان نصف الفصلي
5% الحضور
15% تمارين

6. متطلبات المقرر
الإلمام بإحدي لغات البرمجة وإحدي برامج إدارة نظم قواعد البيانات.

7. أهداف المقرر
التعرف على قواعد البيانات ولماذا الاتجاه الي استخدام نظم قواعد البيانات بدلاً عن النظم التقليدية القديمة ثم كيفية تصميم قاعدة بيانات جديدة وبأسس علمية صحيحة و التعرف علي لغات برامج نظم قواعد البيانات.

8. Elmasri and Shamkant. "Fundamentals of Database Systems".
المراجع المستخدمة
المرجع الاساسي:
Elmasri and Shamkant. "Fundamentals of Database Systems".
5th edition.
مرجع إضافي:
Thomas M. Connolly &Carolyn E.Begg"DataBase Systems,A practical Approach To Design ,Implementation ,And Management Second Edition.
Two references are published by Addison Wesley .

9. Database Systems in two words
This course is an introduction to database systems
Considers questions how to design, implement and use data intensive computer applications
Majority of the practical tasks in industry require applying relatively not complex algorithms to huge amounts of well structured data.Accordingly, efficiency of an application depends on the quality of (logical and physical) data organization.

10. Why Learn Database Systems
Wherever you go, there are databases:
Student records
Airlines and hotels reservations,
Bank accounts
One of the first things people will ask you in an job interview is:
“What do you know about databases?”
Databases are a matured area with a sound theoretical foundation and great practical knowledge

11. محتويات المقرر
1. المفاهيم العامة لقواعد البيانات ومستخدمي قواعد البيانات
Chapter (1):Databases and Database Users
Introduction
1.2 An example
Characteristics of Database Approach
Actors on the Scene
Workers behind the Scene
Advantages of using a DBMS
A Brief History of DB Application
When Not to Use a DBMS

12. Cont. 2.مفاهيم نظم قواعد البيانات ومعماريتها
Chapter(2) : Database Systems Concepts and Architecture
2.1Data Models, Schemas, and Instances.
2.2Three-schema Architecture and Data Independence.
2.3 Database Languages and Interfaces
2.6 Classification of Database Management Systems

13. 3.9 Relationship Types of degree higher than two.
Cont.
3. نموذج الكائنات المرتبطة
Chapter(3): Data Modeling Using The Entity Relationship (ER) Model.
3.1 Using High-Level Conceptual Data Models for Database Design.
3.2 An Example Database Application
3.3 Entity Types, Entity Sets, Attributes, and Keys.
3.4 Relationships, Relationship Types, Roles, and Structural Constraints.
3.5 Weak Entity Types.
3.6 Refining the ER Design for the COMPANY Database.
3.7 ER Diagrams, Naming Conventions, and Design Issues.
3.9 Relationship Types of degree higher than two.

14. Cont. 4 نموذج الكائنات المرتبطة المحسن.
Chapter(4): Enhanced Entity Relationship(EER) Model.

15. Cont. Chapter(5): Relational data Model and Relational Constraints.
5.النموذج العلائقي
Chapter(5): Relational data Model and Relational Constraints.
5.1 Relational Data Model Concepts
5.2 Relational Constraints and Relational Database Schemas
5.3 Update Operations ,transaction ,and Dealing with Constraints Violations

16. 6.1 Unary Relational Operations
6 الجبر العلائقي Chapter(6) the Relational Algebra AND relational calculus
6.1 Unary Relational Operations
6.2 Relational Algebra Operations from set theory
6.3 binary Relational Operations

17. cont. 7. تحويل نموذج الكائنات الي النموذج العلائقي
Chapter (7): ER to Relational Mapping
7.1 relational DB design using ER –to- Relational Mapping.

18. cont. 8. لغة الاستفسارات الهيكلية
8. لغة الاستفسارات الهيكلية
Chapter (8) :Structured Query Language SQL-99:schema Definition, constraints , queries, and views.
8.1 SQL Data Definitions , Constraints and data types
8.2 Specifying Constraints In SQL.
8.3 schema change statements in SQL.
Basic Queries in SQL.
8.5 More Complex SQL Queries.
8.6 Insert . Delete , And Update Statements In SQL.
8.8 Views (Virtual Table) In SQL.

19. Cont. 9. الاعتماد الدالي والتبسيط
Chapter(10):Functional Dependencies and Normalization for relational Databases.
10.1 Informal Design Guidelines for Relation Schemas.
10.2 Functional Dependencies
10.3 Normal forms Based on Primary Keys
10.4 General Definitions of Second and Third Normal Forms.

20. تمارين (1) قراءة ( chapter( 1 . (2) تمرين معملي (1) :
(2) تمرين معملي (1) :
أكتب برنامجا بلغة C++ ينشئ ملفا لتخزين بيانات 30 طالب حيث يحتوي أي سجل للطالب علىخمسة حقول إسم الطالب, رقمه,عامه الدراسي , عمره, وعنوانه.وايضاً يقوم هذا الملف بتخزين بيانات 20 مقرر تدرس للطلاب, أي سجل للمقرر يحتوي على ثلاثة حقول إسم المقرر ,رقم المقرر,والسنة الدراسية التي يدرس بها.
بعد كتابة البيانات في الملف تأكد من أنه تم حفظها بصورة سليمة عن طريق قراءتها من الملف وإستعراضها على الشاشة على شكل تقرير به اسماء الطلاب وارقامهم واسماء المقررات التي يدرسونها . ثم استعرض ايضاً اسماء طلاب السنة الاولى مرتبة حسب الاعمار.

21. CHAPTER (1)

22. Introduction
تستخدم نظم قواعد البيانات في معظم الموؤسسات المختلفة كالبنوك , الموؤسسات التعليمية,مكاتب الحجز الجوي,المصانع الخ
(databases plays a critical rule in almost all areas where computers are used ,including business ,ecommerce, engineering, medicine,…etc)
التطبيقات التقليدية لنظم قواعد البيانات: البيانات إما نصوص text)) اوارقام numbers)).
امثلة للتطبيقات الحديثة لنظم قواعد البيانات:
Multimedia DB systems
Geographical information system (GIS)
Data Warehousing And Data Mining
Interaction Between DB And WWW
Active DBs
Temporal DBs

23. General concepts Definition of DB : collection of related data.
)قاعدة البياتات هي عبارة عن مجموعة من البيانات ذات العلاقة ببعضها البعض(.
this defn is more general.
Essential database characteristics are:
Represents an aspect of the real world (miniworld, UoD),
Well structured (even has a strict regular structure),
Reflects (or should reflect) current state of the UoD,
Has users and applications,
Stored in a permanent (persistent) computer memory, and
Accessed and manipulated using a DBMS
All these characteristics have to be met
UOD :universe of discourse

24. What Is a Database? Student represented in Real World
Facts about world and behaviour of world
represented in
contents and operations of a database
Student
LName
FName
StudId
Major
Ahmed
Amna
04-12
Comp
Ali
Osman
02-34
Math
A/ Alla
Esraa
06-20
Stat
Users
Database

25. Another definition: A DB is a shared collection of logically related data (and description of this data ),designed to meet the information needs of an organization.

26. Definition of Data (Datum)
Data is a value of a property of an individual UoD object or a relationship (between two UoD objects) at a particular period of time.
Example
UoD object(s)
Ali
Ali & CompSci dep
Property
Age
Number of Points
Time
Feb 2005
Value 21
240

27. تختلف أحجام قواعد البيانات كما تختلف درجة تعقيدها.

28. Database Management System (DBMS) نظم ادارة قواعد البيانات
A collection of programs that enable:
Defining (describing the structure),
Constructing (populating by data),
Manipulating (querying, updating),
Preserving consistency,
Protecting from misuse,
Recovering from failure, and
Concurrent using
of a database.

29. Another definition
DBMS: A software system that enables users to define ,create, maintain the database and provides controlled access to this database.
DBMS either general purpose or specific purpose software.

30. Database systems نظم قواعد البيانات
DB+DBMS DB system

31. Example of DB

32. Characteristics of the DB approach
Difference between DB systems(DB approach) and file-based systems (traditional file processing).
Definition of file-based system: A collection of application programs that perform services for the end-users such as production of reports. Each program defines and manages its own data.

33. An example of file based system
Academic office
Academic office files
Data entry and reports
File handling routines
File definition
File definition
Account office
Account office files
Data entry and reports
File handling routines
File definition

34. ماهي عيوب نظم الملفات التقليدية؟
Separation and isolation of data.
Duplication of data.
Data dependence.
Incompatibility of files.
Fixed queries

35. Comparison between DB approach and TFP approach
The main characteristics of DB approach versus TFP approach are:
Self-Describing Nature of a Database System - it has a complete definition or description of the database structure and constraints. This definition is stored in the system catalog, which contains information such as the structure of each file, the type and storage format of each data item, and various constraints on the data. This information stored in the system catalog is called, Meta-data and it describes the structure of the primary database. This allows the DBMS software to work with different databases (Fig 1.1)

36. An example of a database catalog
Relations
Relation name
No-of-columns
STUDENT 4
COURSE
SECTION 5
GRADE REPORT
PREREQUISITE 3 2
Columns
Column-name
Data-type
Belong-to-relation
name
Character(30)
STUDENT
Student-number
Character(4)
Class
Integer(1)
Major
Major-type

37. Cont.
Insulation between Programs and Data and Data Abstraction - Called program-data independence. Allows changing data storage structures and operations without having to change the DBMS access programs. The structure of data files is stored in the DBMS catalog separately from the access programs.

38. Cont.
Data Abstraction: A data model is used to hide storage details and present the users with a conceptual view of the database.
Support of Multiple Views of the Data - Each users may see a different view of the database, which describes only the data of interest to that user. (fig 1.4)

39. بسم الله الرحمن الرحيم
Lecture( 2)

40. Cont. 5- Sharing of Data and Multiuser Transaction Processing :
These types of application is called online transaction processing applications(OLTP)
The DBMS must include concurrency control software to ensure that the result of multiuser access is correct.

41. Database administrator (DBA):
Database system users
Database administrator (DBA):
1-Administering the primary resource of DBsystem (DB itself) and DBMS (secondary resource).
2- responsible for authorizing access to the db, for coordinating and monitoring its use.
3- responsible for acquiring software and hardware when needed.
4-Solving the problems of the system such as security or poor system response time.

42. Cont.
DB designers:
responsible for identifying the data to be stored and for choosing appropriate structures to represent and store this data. This done after communicate with all db users in order to understand their requirements.

43. Cont.
End users: - people whose jobs require access to the database for querying, updating, and generating reports.
There are several categories of end users :
Casual end users (not formal): access db from time to time (like managers)
Naïve or Parametric end users :querying and updates db using standard types of queries (called canned transaction).
Sophisticated end users like engineers, scientists.
Stand alone users: using ready made program packages(for example tax package(.

44. Cont.
System Analysts and Application Programmers (Software Engineers) - System analysts determine the requirements of end users, and develop specifications for transactions. Application programmers implement these specifications and programs. Such analysts and programmers nowadays called software engineers.
 read section 1.5.

45. Advantages of using DBMS
Controlling redundancy:
redundancy means that storing the same data multiple times in the DB.
Redundancy problems:
1-Duplication of efforts.
2-storage space is wasting
3-Inconsistency of data
In DB approach: store each logical data item (such as a student's name) in only one place.
In some cases redundancy is necessary to improve system performance and DBMS has capability to control such redundancy. FIGURE(1.5)

46. Cont. Restricting Unauthorized Access:-
the DBA uses security and authorization subsystem (provided by DBMS) in order to specify account restrictions.
Providing Persistent Storage for Program Objects and Data Structures. Compatibility between ODBMS (object store) and OOPL(C++,JAVA).
Permitting Inferencing and actions Using Rules :-
capability for defining deduction rules for inferencing new information from the stored database facts. (active DB system ).

47. Providing Storage Structures For Efficient Query Processing:
CONT.
Providing Storage Structures For Efficient Query Processing:
DB is stored on disk, so DBMS must provide specialized data structures to speed up disk search.
DBMS often has a buffering module that maintains parts of the DB in memory buffers.
Query processing and optimization module of the DBMS is responsible for choosing an efficient query execution plan for each query.
Choosing appropriate data structure is a part of physical DB design and tuning .

48. Cont. to satisfy users with varying levels of technical knowledge.
Providing Multiple User Interfaces :-
to satisfy users with varying levels of technical knowledge.
Interfaces for casual users, form style and menu driven (GUIs).
7-Representing Complex Relationships Among Data:-a DBMS must have the capability to represent a variety of complex relationships among the data as well as to retrieve and update related data easily and efficiently.

49. Cont. capability for defining and enforcing constraints
Enforcing Integrity Constraints:-
capability for defining and enforcing constraints
(e.g., specifying a data type for each data item).
Providing Backup and Recovery:-
A DBMS must provide facilities for recovering from hardware or software failures. The backup and recovery subsystem o f a DBMS is responsible for recovery.
Read section 1.7.

50. When Not To Use a DBMS Disadvantages Of DBMS:
High initial investment in hardware, software, and training.
Generality that a DBMS provides for defining and processing data.
Overhead for providing security, concurrency control, recovery, and integrity functions.

51. cont.
The following are the situations where the using of a DBMS is not suitable:-
The database and applications are simple, well defined, and not expected to change.
Real-time requirements for some program may not be met because of DBMS overhead.
Multiple-user access to data is not required.

52. Good bye chapter one

53. Chapter(2) :
Database system concepts and architecture.

54. Database approach provides some level of data abstraction by hiding details of data storage.
Data Model: A data model is a collection of concepts that can be used to describe the structure of a database. By structure of a database we mean the data types, relationships, and constraints that should hold on the data.
(مجموعة من المفاهيم تستخدم لوصف بنية قاعدة البيانات)
Some Data models include a set of basic operations for specifying retrievals and updates on the database.
Data models also allows the database designer to specify a set of valid user defined operations on the database objects.

55. Categories of data model
High-level or conceptual data models
Low-level or physical data models
Representational or implementation data models

56. High-level or conceptual data models
المفاهيم في هذا النوع اقرب لفهم المستخدم العادي(غير المتخصص في الحاسوب) ولذا لا تطبق هذه المفاهيم مباشرةً فى الحاسوب.
يتم تحديد هذا النموذج في الخطوة الثانية لتصميم قاعدة البيانات.
امثلة:نموذج الكائنات((entity relationship model
نموذج الكائنات المحسن enhanced entity relationship model ) )

57. Low-level or physical data models
المفاهيم في هذا النوع تتعلق بوصف كل التفاصيل عن كيفية تخزين البيانات في الحاسوب.
يوصف نسق السجلات,تنظيم السجلات وممرات الوصول للسجلات
((access paths
امثلة :unifying model, frame memory

58. Representational or implementation data models
المفاهيم في هذا النوع قد تفهم بواسطة المستخدم العادي. ولكن لاتخفي كل تفاصيل التخزين و تطبق هذه المفاهيم مباشرةً فى الحاسوب.
اي DBMS لها نموذج تطبيقي خاص بها.
تستخدم في هذه النماذج السجلات لوصف البيانات ولذ يطلق عليها
(Record-based data models).
امثلة:
relational model(يستخدم في معظم ال DBMS الحالية).
Hierarchical and network models (تستخدم في الانظمة القديمة).
Object models(تستخدم في الODBMS)

59. Schemas, Instances, and Database State
خارطة قاعدة البيانات database schema)):وصف قاعدة البيانات(description of database)
تحدد خارطة قاعدة البيانات اثناء تصميم قاعدة البيانات وهي نادراً مايحدث بها تحديث .
في معظم نماذج البيانات تكون الخارطة عبارة عن رسم توضيحي( (diagram

60. مثال لخارطة قاعدة بيانات
student
Name
Studnumber
Class
Major
course
Coursename
Coursenumber
Credithours
Department
Grade report
Studnumber
Coursenumber
Semno
Grade
prerequisite
Coursenumber
Prerequisitenumber

61. قاعدة البيانات للخارطة اعلاه
Student
Name
Studnumber
Class
Major
Ali
04-43 4 cs
Osman
05-24 2
stat
Coursename
Coursenumber
Credithours
Department
Introd to computer science
c102 4 Cs
Data structure
c202
Discrete math
c201 3
Into to DB
c406 cs
Course

62. Cont. 04-43 1 A 05-24 c202 B c406 c102 c202 Studnumber Coursenumber
Grade report
Studnumber
Coursenumber
Semno
Grade
04-43
c406 1 A
05-24
c202 B
prerequisite
Coursenumber
Prerequisitenumber
c406
c102
c202

63. Database state
البيانات في قاعدة البيانات فى لحظة معينة تسمى ب database state, or database snapshot or current set of occurrences or instances in DB.
في قاعدة البيانات اعلاه أي) schema construct ( لها set of instances .

64. الفرق بين database state وال database schema :
عند اتشاء قاعدة بيانات جديدة تحدد اولاً الخارطة ,في هذه اللحظة تكون ال DBstate خالية (empty state)
بمجرد تحميل قاعدة البيانات بالبيانات الاولية تتحول حالة قاعدة البيانات الى initial state ,أي تحديث يحول الى new state
ال DBMS مهمتها التأكد ان حالة قاعدة البيانات دائماً صحيحة (valid state) وذلك بعدم خرق أي قيد من القيود الموضحة على الخارطة.
هات مثال لتحديث صحيح وتحديث غير صحيح.