1. defines and regulates the collection, storage, management, use of data
1.1. 5 major parts of a database system
1.1.1. Hardware
1.1.1.1. All the system's physical devices
1.1.2. Software
1.1.2.1. Operating system software
1.1.2.2. DBMS software
1.1.2.3. Application programs and utility software
1.1.3. People
1.1.3.1. System and database administrators
1.1.3.2. Database designers
1.1.3.3. Systems analyst and programmers
1.1.3.4. End users
1.1.4. Data
1.1.4.1. The collection of facts stored in the database
1.1.4.2. New node
1.1.5. Procedures
1.1.5.1. Instructions and rules that govern the design and use of the database system
2. Data redundancy
2.1. File system structure makes it difficult to combine data from multiple sources
2.2. Organizational structures promotes storage of same data in different locations
2.2.1. Data redundancy
2.2.1.1. Same data stored unnecessarily in different places
2.2.1.1.1. 1. islands of information
2.2.1.1.2. 2. Increases the probability of having different versions of the same data
2.2.1.2. Possible results of uncontrolled data redundancy
2.2.1.2.1. 1. Poor data security
2.2.1.2.2. 2. Data inconsistency
2.2.1.2.3. 3. Data-entry errors
2.2.1.2.4. 4. Data integrity problems
2.2.2. Data anomalies
2.2.2.1. Develop when not all the required changes in the redundant data are made successfully
2.2.2.1.1. Update anomalies
2.2.2.1.2. Insertion anomalies
2.2.2.1.3. Deletion anomalies
2.3. Data stored in different locations unlikely to be updates consistently
3. Database management system (DBMS)
3.1. Collection of programs
3.2. Manage structure and control access to data
3.3. The intermediary between the user and the database
3.3.1. Advantages of a DBMS
3.3.1.1. Improved data sharing
3.3.1.2. Improved data security
3.3.1.3. Improved data access
3.3.1.4. Improved decision making
3.3.1.5. Minimized data inconsistency
3.3.2. Disadvantage of DBMS
3.3.2.1. Increased cost
3.3.2.2. Management complexity
3.3.2.3. Maintaining currency
3.3.2.4. Vendor dependence
3.3.2.5. Frequent update / replacement cycles
3.4. Enables data to be shared
3.5. Presents the end user with an integrated view of data
3.6. Provides more efficient and effective data management
3.7. Improves sharing, security, integration, access, decision-making, productivity
4. Problems
4.1. Effect the information that can be created as well as data accuracy
4.1.1. 1. Lengthy development times
4.1.2. 2. Difficulty of getting quick answers
4.1.3. 3. Complex system administration
4.1.4. 4. Lack of security and limited data sharing
4.1.5. 5. Extensive programming
5. Dependence (practical significance of data dependence is the difference between logical and physical format)
5.1. Structural
5.1.1. Access to a file is dependent on its own structure
5.1.2. All file programs are modified to conform to a new file structure
5.2. Data
5.2.1. Data access changes when data storage characteristic change
6. Independence
6.1. Structural
6.1.1. File structured is changed without affecting the application's liability to access the data
6.2. Data
6.2.1. Data storage characteristic are changed without affecting the program's ability to access the data
7. Database system
8. DBMS functions
8.1. Data dictionary management
8.1.1. Stores definitions of data elements and relationships in a data dictionary
8.1.2. Changes automatically recorded in the dictionary
8.1.3. Provides data abstraction, removes structural and data dependency
8.2. Data storage management
8.2.1. Creates and manages complex structures required for data storage
8.2.2. Performance tuning: activities that make the database perform more efficiently
8.2.3. Stores the database in multiple physical data files
8.3. Data transformation and presentation
8.3.1. Transform data entered to conform to required data structures
8.3.2. Transforms physically retrieved data to conform user's logical expectations
8.4. Security management
8.4.1. Creates a security system that enforces user security and data privacy
8.4.2. Determine which users can access the database, which items can be accessed
8.5. Multiuser access control
8.5.1. Uses sophisticated algorithms to ensure concurrent access does not affect integrity
8.6. Backup and recovery management
8.6.1. Enables recovery of the database after a failure
8.7. Data integrity management
8.7.1. Minimizes redundancy and maximizes consistency
8.8. Access languages and application programming interfaces
8.8.1. Query language
8.8.1.1. Lets the user specify what must be done without having specify how
8.8.2. Structured Query Language
8.8.2.1. De facto query language and data access standard supported by the majority DBMS vendor
8.9. Database communication interfaces
9. The differences between:-
9.1. Data
9.1.1. Raw facts
9.1.2. Formatted for storage, processing and presentation
9.1.3. Building blocks of information
9.2. Information
9.2.1. Result of processing raw data to reveal meaning
9.2.2. Requires context to reveal meaning
9.2.3. Foundation of information
9.2.3.1. Accurate, relevant, timely information is the key to good decision making
9.2.3.1.1. Good decision making is the key to organizational survival
9.2.4. Bedrock of knowledge
9.2.5. Produced by processing data
9.2.6. Reveal meaning in data
10. Historical Roots: Files and File Systems
10.1. Reasons:
10.1.1. Complexity of database design easier to understand
10.1.2. Understanding file system problems helps to avoid problems with DBMS systems
10.1.3. Knowledge of file system useful for converting file system to database system
10.2. Composes of collection of file holders
10.2.1. Each tagged and kept in cabinet
10.2.2. Organized by expected use
10.3. Content of each file holder logically related
10.4. Manual system served as a data repository for small data collections
10.4.1. Cumbersome for large collections
10.5. Data processing (DP) specialist
10.5.1. Wrote software that managed the data
10.5.2. Designed the application programs
10.6. Number of files increased, file systems evolved
10.6.1. Store, retrieve and modify data
10.6.2. Owned by individual or department that commissioned its creation
10.7. Data processing (DP) manager
11. Evolution of file system data processing
11.1. 1. Manual file systems
11.1.1. Accomplished thru a system of file holders and filling cabinets
11.2. 2. Computerized file systems
11.2.1. Data processing specialist created a computer-based system to track data and produce required report
11.3. 3. File system redux (modern end-user productivity tools)
12. Database
12.1. Shared, integrated computer structure that stores a collection of data
12.1.1. Metadata
12.1.1.1. Data about data
12.1.1.2. Provides description of data characteristics and relationships in data
12.1.1.3. Complements and expands value of data
12.1.2. End user data
12.1.2.1. Raw fact of interest to end user
12.2. Can be classified according to:
12.2.1. Unstructured data exists in its original state
12.2.2. Structured data results from formating. (applied based on type of processing to be performed
12.2.3. Semi-structured data
12.2.3.1. Processed to some extent
12.3. Types of database
12.3.1. Single-user database
12.3.1.1. Supports only one user at a time
12.3.1.1.1. Desktop database- single-user, runs on PC
12.3.2. Multiuser database
12.3.2.1. Supports multiple users at the same time
12.3.2.1.1. Workgroup database- supports a small number of users or a specific department
12.3.2.1.2. Enterprise database- supports a large number of users across many department
12.3.3. Centralized database
12.3.3.1. Data located at a single site
12.3.4. Distributed database
12.3.4.1. Data distributed across several different sites
12.3.5. Analytical databse
12.3.5.1. Stores historical data and business metric used exclusively for tactical or strategic decision making
12.3.5.1.1. Data warehouse
12.3.5.1.2. Online analytical processing (OLAP)
12.3.5.1.3. Business intelligence
12.3.6. Cloud database
12.3.6.1. Created and maintained using cloud data services
12.3.7. General purpose database
12.3.7.1. Contains a wide variety of data used in multiple disciplines
12.3.8. Discipline-specific database
12.3.8.1. Contains data focused on specific subject areas
12.3.9. Operational database
12.3.9.1. Designed to support a company's day-to-day operations
12.4. Why database design is important
12.4.1. Focuses on design of database structure used for end-user data
12.4.2. Well-designed database
12.4.2.1. Facilitates data management
12.4.2.2. Generates accurate and valuable information
12.4.3. Poorly designed database
12.4.3.1. Causes difficult-to-trace errors
12.4.3.2. Lead to poor decision making
13. Characteristic of data
13.1. - ubiquitous
13.2. -pervasive
14. Basic terminology
14.1. 1. Data
14.1.1. Raw fact - Telephone number, a birth date, a customer name
14.2. 2. Field
14.2.1. A characters or a group of characters that has specified meaning
14.2.2. Used to define and stores data
14.3. 3. Record
14.3.1. A logically connected set of one or more fields
14.3.2. Ex: The fields that constitute a record of a customer might consists of the customer's name, phone number
14.4. 4. File
14.4.1. A collection of related record