1. Database Management:

2. Files and Databases
File: A collection of records or documents dealing with one organization, person, area or subject. (Rowley)
Manual (paper) files
Computer files
Database: A collection of similar records with relationships between the records. (Rowley)
graphic, statistical, business data, images, etc.
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3. Database
A Database is a collection of stored operational data used by the application systems of some particular enterprise.
(C.J. Date)
Paper “Databases”
Still contain a large portion of the world’s knowledge
File-Based Data Processing Systems
Early batch processing of (primarily) business data
Database Management Systems (DBMS)
IS 257 – Spring 2004

4. Terms and Concepts Database Management System -- DBMS
Software system used to define, create, maintain and provide controlled access to the database and repository
IS 257 – Spring 2004

5. Terms and Concepts Repository Data Dictionary
The place where all metadata for a particular database is stored
may also include information on relationships between files or tables in a particular database
IS 257 – Spring 2004

6. Terms and Concepts Metadata Data about data
In DBMS means all of the characteristics describing the attributes of an entity, E.G.:
name of attribute
data type of attribute
size of the attribute
format or special characteristics
Characteristics of files or relations
name, content, notes, etc.
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7. From File Systems to DBMS
Problems with File Processing systems
Inconsistent Data
Inflexibility
Limited Data Sharing
Poor enforcement of standards
Excpensive program maintenance
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8. DBMS Benefits Minimal Data Redundancy Consistency of Data
Integration of Data
Sharing of Data
Ease of Application Development
Uniform Security, Privacy, and Integrity Controls
Data Accessibility and Responsiveness
Data Independence
Reduced Program Maintenance
IS 257 – Spring 2004

9. Terms and Concepts Data Independence
Physical representation and location of data and the use of that data are separated
The application doesn’t need to know how or where the database has stored the data, but just how to ask for it.
Moving a database from one DBMS to another should not have a material effect on application program
Recoding, adding fields, etc. in the database should not affect applications
IS 257 – Spring 2004

10. Database Environment CASE Tools DBMS User Interface Application
Programs
Repository
Database
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11. Database Components DBMS Application Programs Design tools Database
===============
Design tools
Table Creation
Form Creation
Query Creation
Report Creation
Procedural
language
compiler (4GL)
=============
Run time
Form processor
Query processor
Report Writer
Language Run time
User
Interface
Applications
Application
Programs
Database
Database contains:
User’s Data
Metadata
Indexes
Application Metadata
IS 257 – Spring 2004

12. Types of Database Systems
PC Databases
Centralized Database
Client/Server Databases
Distributed Databases
Database Models
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13. PC Databases
E.G.
Access
FoxPro
Dbase
Etc.
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14. Centralized Databases
Cental
Computer
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15. Client Server Databases
Network
Client
Database
Server

16. Distributed Databases
Location B
Location C
computer
computer
Homogeneous
Databases
computer
Location A
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17. Distributed Databases
Client
Heterogeneous
Or Federated
Databases
Remote
Comp.
Local Network
Database
Server
Comm
Server
Remote
Comp.
Client
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18. Terms and Concepts Database Application
An application program (or set of related programs) that is used to perform a series of database activities:
Create
Read
Update
Delete
On behalf of database users
IS 257 – Spring 2004

19. Range of Database Applications
PC databases
Usually for individual
WorkGroup databases
Small group use where everyone has access to the database over a LAN
Departmental databases
Larger than a workgroup – but similar
Enterprises databases
For the entire organization over an intranet (or sometimes the internet)
IS 257 – Spring 2004

20. Data Models A collection of tools for describing:
Data relationships
Data semantics
Data constraints
Object-based logical models
Entity-relationship model
Object-oriented model
Semantic model
Functional model
Record-based logical models
Relational model (e.g., SQL/DS, DB2)
Network model
Hierarchical model (e.g., IMS)
CIS-552

21. Entity-Relationship Model
Example of entity-relationship model
customer-street
social-security
account-number
customer-city
customer-name
balance
depositor
customer
account
CIS-552

22. Relational Model Example of tabular data in the relational model:
CIS-552

23. Data Definition Language (DDL)
Specification notation for defining the database schema
DDL compiler generates a set of tables stored in a data dictionary
Data dictionary contains metadata
(data about data)
Data storage and definition language – special type of DDL in which the storage structure and access methods used by the database system are specified
CIS-552

24. Terms and Concepts Database activities: Create Read Update Delete
Add new data to the database
Read
Read current data from the database
Update
Update or modify current database data
Delete
Remove current data from the database
IS 257 – Spring 2004

25. Terms and Concepts Enterprise Entity Attributes Data values
Organization
Entity
Person, Place, Thing, Event, Concept...
Attributes
Data elements (facts) about some entity
Also sometimes called fields or items or domains
Data values
instances of a particular attribute for a particular entity
IS 257 – Spring 2004

26. Terms and Concepts Records File
The set of values for all attributes of a particular entity
AKA or “rows” in relational DBMS
File
Collection of records
AKA “Relation” or “Table” in relational DBMS
IS 257 – Spring 2004

27. Terms and Concepts Key Primary Key
an attribute or set of attributes used to identify or locate records in a file
Primary Key
an attribute or set of attributes that uniquely identifies each record in a file
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28. Terms and Concepts DA DBA
Data administrator - person responsible for the Data Administration function in an organization
Sometimes may be the CIO - Chief Information Officer
DBA
Database Administrator - person responsible for the Database Administration Function
IS 257 – Spring 2004

29. Terms and Concepts Data Administration Database Administration
Responsibility for the overall management of data resources within an organization
Database Administration
Responsibility for physical database design and technical issues in database management
Data Steward
Responsibility for some subset of the organization’s data, and all of the interactions (applications, user access, etc.) for that data
IS 257 – Spring 2004

30. Terms and Concepts Models (1) Levels or views of the Database
Conceptual, logical, physical
(2) DBMS types
Relational, Hierarchic, Network, Object-Oriented, Object-Relational
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31. Models (1) Conceptual Model Logical Internal Model requirements
External
requirements
Application 1
Application 2
Application 3
Application 4
Internal Model
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32. Data Models(2): History
Hierarchical Model (1960’s and 1970’s)
Similar to data structures in programming languages.
Books
(id, title)
Publisher
Subjects
Authors
(first, last)
IS 257 – Spring 2004

33. Data Models(2): History
Network Model (1970’s)
Provides for single entries of data and navigational “links” through chains of data.
Subjects
Books
Authors
Publishers
IS 257 – Spring 2004

34. Data Models(2): History
Relational Model (1980’s)
Provides a conceptually simple model for data as relations (typically considered “tables”) with all data visible.
IS 257 – Spring 2004

35. Data Models(2): History
Object Oriented Data Model (1990’s)
Encapsulates data and operations as “Objects”
Books
(id, title)
Publisher
Subjects
Authors
(first, last)
IS 257 – Spring 2004

36. Data Models(2): History
Object-Relational Model (1990’s)
Combines the well-known properties of the Relational Model with such OO features as:
User-defined datatypes
User-defined functions
Inheritance and sub-classing
IS 257 – Spring 2004

37. Database System Life Cycle
Growth,
Change, &
Maintenance 6
Operations 5
Integration 4
Design 1
Conversion 3
Physical
Creation 2
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38. Design Determination of the needs of the organization
Development of the Conceptual Model of the database
Typically using Entity-Relationship diagramming techniques
Construction of a Data Dictionary
Development of the Logical Model
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39. Conversion
Convert existing data sets and applications to use the new database
May need programs, conversion utilities to convert old data to new formats.
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40. Integration
Integration of converted applications and new applications into the new database
IS 257 – Spring 2004

41. Operations All applications run full-scale
Privacy, security, access control must be in place.
Recovery and Backup procedures must be established and used
IS 257 – Spring 2004

42. Growth, Change & Maintenance
Change is a way of life
Applications, data requirements, reports, etc. will all change as new needs and requirements are found
The Database and applications and will need to be modified to meet the needs of changes
IS 257 – Spring 2004

43. Data Manipulation Language (DML)
Language for accessing and manipulating the data organized by the appropriate data model
Two classes of languages
Procedural – user specifies what data is required and how to get those data
Nonprocedural – user specifies what data is required without specifying how to get those data
CIS-552

44. Transaction Management
A transaction is a collection of operations that performs a single logical function in a database application.
Transaction-management component ensures that the database remains in a consistent (correct) state despite system failures (e.g. power failures and operating system crashes) and transaction failures.
Concurrency-control manager controls the interaction among the concurrent transactions, to ensure the consistency of the database.
CIS-552

45. Storage Management
A storage manager is a program module that provides the interface between the low-level data stored in the database and the application programs and queries submitted to the system.
The storage manager is responsible for the following tasks:
Interaction with the file manager
Efficient storing, retrieving, and updating of data
CIS-552

46. Database Administrator
Coordinates all the activities of the database system; the database administrator has a good understanding of the enterprise’s information resources and needs:
Database administrator’s duties include:
Schema definition
Storage structure and access method definition
Schema and physical organization modification
Granting user authority to access the database
Specifying integrity constraints
Acting as liaison with users
Monitoring performance and responding to changes in requirements
CIS-552

47. Overall System Structure
indices
Statistical data
Data files
Data dictionary
disk storage
CIS-552