Information Management: Data and Metadata

The Need for Information

• Organizations rely on a vast assortment of information
• Valued information can be an asset to organizations with careful strategy
• IT contributes to improved information management
• Businesses gain economic value from IT through competitiveness, high productivity and greater revenue

Data, Information & Metadata

• Data is defined as recorded facts that can be accessed
• Examples of data formats are text, numbers, figures, graphics, images and audio/video recordings
• Data can be recorded with the intention to be re-used by an intended user
• Information is data accessed by a user for a specific reason
• Accessing needed information requires performing an activity such as searching, processing or manipulating data
• Metadata describes the structure and properties of data
• Metadata is essential for the proper understanding and use of data

Organizing Data

• Data model provides the principles for organizing data
• Data structure is described as a logical collection of data elements
• Data element is described as a group of data items
• Data item is the simplest element of data and is described at atomic

File-Based Data Organization

• The file based model was a popular data model for decades.
• The file-based model is logically organized with constructs of fields (data items), records (data elements), and files (data structures).

File-Based System Limitations

• Defines the collection as application programs that performs service for end-users
• Each program defines and manages its data
• Lacks efficient access, no direct query support
• Directory creation and hierarchical organization are limited
• Lacks sophisticated support for concurrency
• Durability is not ensured

File System Drawbacks

• Data redundancy and inconsistency occur because of multiple file formats and information duplication.
• Difficulty in accessing data because writing a program is required to carry out a new task
• Data isolation is an issue, since multiple files are in different formats making it hard to write new retrieval programs
• Integrity problems arise because integrity constraints become part of the program code, and new constraints are hard to add
• Atomicity of updates results in failures potentially leaving inconsistent databases
• Concurrent access to files necessitates performance, but uncontrolled concurrent accesses lead to inconsistencies
• Security problems can arise

Database Approach

• Controlled database access options include a security system, an integrity system, a concurrency control system, a recovery control system and a user-accessible catalog.

What is a Database?

• A database is a shared collection of logically related data, and its description, to meet an organization's needs
• Organized information that can be easily accessed, managed, and updated
• The system catalog (metadata) provides data description and enables program-data independence
• A database can store significant information and allow for information sharing and flexible use of data in various applications

Application Examples

• Typical applications include supermarket stock control, university registration systems, video/car rental services and travel agencies
• Additional examples are library information systems, reservations systems, and banking systems
• Bioinformatics (e.g. gene databases), Criminal Justice (e.g. fingerprint matching), Multimedia Systems and even the web use databases.

Database Terminologies

• A table is a group of related records
• Database is a structured, related data collection on a computer, organized for efficient access
• Database metadata represents database structure including content not directly the data itself
• Metadata contains the names of the data structures, data types, descriptions, and other characteristics.
• A field is an information category in a column; a record is a group of related fields

Primary Key

• Relates to a field value that is unique to a record

Data Types

• The type of data stored in a field

Database Management System (DBMS) Details

• Manages the creation, maintenance, and database use, along with the organizations end users
• Serves to create, manage and manipulate large streams of data
• DBMS software allows users to define, create, maintain and control the access to a database
• A database application program interacts via SQL to the DBMS

Database Management System (DBMS) Uses

• Used for creating databases, insertion, storage, retrieval, update, and deletion of data
• Maintenance of databases
• A computer-based system intended to enhance efficient interaction between users and database information

Typical DBMS Functionality

• Defines a database using data structures, types and constraints
• Constructs the database via secondary mediums
• Manipulates the database via reporting, insertion, deletion, modification etc.
• Maintains concurrency and sharing by users while maintaining validity and consistency

DBMS Features

• Protection measures to prevent unauthorized access
• Active processing (taking internal actions on data)
• Presentation of data or visualization

Benefits of a DBMS

• Data independence is achieved through application programs being as independent as possible from data storage details
• Efficient data access with sophisticated storage and retrieval techniques
• Application development time is reduced
• Data integrity and security is achieved by enforcing integrity constraints
• Data centralization streamlines data administration
• Supports concurrent access and crash recovery

Other DBMS Benefits

• Controlling redundancy
• Data consistency
• More information from the same amount of data
• Data sharing
• Improved integrity
• Improved security
• Enforcement of standards
• Economies of scale
• Balance conflicting requirements
• Improved data accessibility and responsiveness
• Increased productivity
• Improved maintenance through data independence
• Increased concurrency
• Improved backup and recovery services

DBMS System Architecture

• Consists of front-end applications, which provide easy interaction between the database and end users
• End-users (business users) use systems to support their work
• Indirect interaction involves end-users communicating with the database via front-end apps.
• Direct interaction involves end-users communicating directly with the database

Steps in Database Systems Development

• First is defining requirements
• Next, is database modeling
• Then is its implementation
• After which, is its development
• Followed by database use
• Ended by, administration and ongoing Maintenance

Requirements of Definition

• Collection, definition, and visualization, identifying necessary data, capabilities and functionalities.
• Collection is clearly defined and stated in what is written, and then visualized
• Collection is a critical step in the development of the database

Visualization

• A conceptual database model is used to create visualization of requirement with use of entity relationship ER modeling

Iterative Nature

• Is within the database requirements collection, definition and the visualization process.

Database Modeling Details

• Logical database modeling is creation of implentable database by DBMS Software
• This follows a conceptual database modeling
• A conceptual model creates a visualization of requirements from the collection period
• From the database model step, it is used as a blueprint for the actual (logical database model)
• The logical model is the actual model, is created during modeling step and implemented during the DBMS

Steps In Implementation and the Structure Query Language (SQL)

• DBMS to implement the database model
• Usage of Relational DBMS (RDBMS)
• SQL is a language used by relational DBMS software
• SQL includes commands for creating, modifying, and deleting database structures (these are used during database implementation)

Developing Front-End Apps

• Designing and creating apps for use by end-users
• Built on database model and requirement specification
• Contains interfaces such as forms and accessible reports via menus.

Database System Releasing

• Used for use by the end consumers and population to its final release

Database In Use

• Insertion, modification, deletion, and retrieval

System Database Administration and Maintenance

• Activities to support the database for end use including helping with technical and general issues
• Provide security for information
• Ensure sufficient hard drive space
• Implementing backup and recovery procedures.

Database Scope

• Scope can range in size from single user, to a large business
• These have the same fundamentals in development (requirements, modelling, implementation etc.)

Database Analysts, Designers, and Developers

• Analysts are involved in visual collection, definition, and visual stage
• Designers are database modelers involved in architectures of database modeling
• Developers are in charge of implementing the database as working, in the DBMS Software.

Database System: Front End Applications

• Collecting, designing, and defining the needs in charge of analysts
• Developers in charge of front-end apps design

DBA (Database Administrators) and Users

• DBA tasks related to task of maintenance within the system

System: End Users and Complexity

• Uses it to support work or personal tasks
• Users will differ in
• How technical they are
• How much data they need
• how often they access it

Drawback of DMBS

• Complexity,
• Size,
• Cost to maintain,
• hardware costs,
• Conversion costs
• Performance
• Higher Failure Rate

Oracle Databases

• Is a popular software package for use, it also includes:
• IBM DB2 - Microsoft SQL Server - Sybase
• Informix
• PostgreSQL
• MySQL
• Microsoft Access