Database Development and Administration

Database Administrator (DBA)

• In charge of enterprise database development
• Improves the integrity and security of organizational databases
• Uses Data Definition Language (DDL) to develop and specify data contents, relationships, and structure
• Stores these specifications in a data dictionary or a metadata repository

Data Dictionary

• Contains data about data (metadata)
• Relies on specialized software component to manage a database of data definitions
• Contains information on:
  • The names and descriptions of all types of data records and their interrelationships
  • Requirements for end users’ access and use of application programs
  • Database maintenance
  • Security

Database Development Phases

• Data planning process
• Database design process
• Data resource management

Data Planning Process

• Develop an enterprise model that defines the basic business process of the enterprise
• Define the information needs of end users in a business process
• Identify the key data elements that are needed to perform specific business activities (entity relationship diagrams)

Entity Relationship Diagram

• Represents data relationships in a business process

Database Design Process

• Data relationships are represented in a data model that supports a business process
• Logical design:
  • Schema: overall logical view of relationships
  • Subschema: logical view for specific end users
  • Data models for DBMS
• Physical design:
  • How data are to be physically stored and accessed on storage devices

Logical and Physical Database Views

• Logical view: represents data relationships and structure
• Physical view: represents how data is physically stored and accessed

Data Resource Management

• Uses data management, data warehousing, and other IS technologies
• Manages data resources to meet the information needs of business stakeholders
• Data stewards:
  • Dedicated to establishing and maintaining the quality of data
  • Need business, technology, and diplomatic skills
  • Focus on data content

Types of Databases

• Operational databases
• Distributed databases
• External databases
• Data warehouses

Operational Databases

• Stores detailed data needed to support business processes and operations
• Examples: customer, human resource, inventory

Distributed Databases

• Copies or parts of databases stored on servers at multiple locations
• Improves database performance at worksites
• Advantages:
  • Protection of valuable data
  • Data can be distributed into smaller databases
  • Each location has control of its local data
  • All locations can access any data, anywhere
• Disadvantages:
  • Maintaining data accuracy
• Replication:
  • Look at each distributed database and find changes
  • Apply changes to each distributed database
  • Very complex
• Duplication:
  • One database is master
  • Duplicate the master after hours, in all locations
  • Easier to accomplish

External Databases

• Databases available for a fee from commercial online services, or free from the Web
• Examples: hypermedia databases, statistical databases, bibliographic and full text databases
• Search engines like Google or Yahoo are external databases

Hypermedia Databases

• Contains hyperlinked pages of multimedia
• Interrelated hypermedia page elements, rather than interrelated data records

Components of Web-Based System

• Web browser (or client)
• Web application server
• Database server

Data Warehouses

• Stores static data that has been extracted from other databases in an organization
• Central source of data that has been cleaned, transformed, and cataloged
• Data is used for data mining, analytical processing, analysis, research, decision support
• Data warehouses may be divided into data marts:
  • Subsets of data that focus on specific aspects of a company (department or business process)