Chapter 11 Data Administration, Database Administration, and Data Dictionaries Fundamentals of Database Management Systems by Mark L. Gillenson, Ph.D. University of Memphis Presentation by: Amita Goyal Chin, Ph.D. Virginia Commonwealth University John Wiley & Sons, Inc.

Chapter Objectives Define and compare data administration and database administration. List and describe the advantages of data administration. List and describe the advantages of database administration.

Chapter Objectives List and describe the responsibilities of data administration. List and describe the responsibilities of database administration.

Chapter Objectives Explain the concept of metadata. List and describe such metadata realizations as passive and active data dictionaries, relational DBMS catalogs, and data repositories.

Database Management The “people side” of database management consists of two parts: Data Administration Database Administration

Data Administration A planning and analysis function that is responsible for: setting data policy and standards promoting the company’s data as a competitive resource accounting for the use of data providing liaison support to systems analysts during application development

Database Administration More operationally oriented. Responsible for the day-to-day monitoring and management of the company’s various active databases. Responsible for providing liaison support to program designers during application development. Carries out many of the policies set by data administration.

Advantages of Data and Database Administration Data as a shared corporate resources. Efficiency in job specialization. Operational management of data. Managing externally acquired databases. Managing data in the decentralized environment.

Data as a Shared Corporate Resource Virtually all aspects of business have become dependent on their information systems and the data flowing through them. Data may well be the most important corporate resource because it describes all of the others.

Data as a Shared Corporate Resource The effective use of its data can give a company a significant competitive advantage. Data, like other resources, tends to be scarce. The dedicated departments that manage the company’s data are the data administration and database administration departments.

Efficiency in Job Specialization Many of the functions involved in the management of data are highly specialized and require specific expertise. This argues for a full-time staff of specialists who do nothing but manage a company’s data and databases.

Operational Management of Data At the operational level, for the day-to-day management of the company’s production databases, an independent department must be responsible. Data should be managed by an independent group whose loyalty is to the overall company and not to any individual function.

Managing Externally Acquired Databases Some databases are not designed by a company’s own personnel but are acquired as part of purchased software packages. For example, Enterprise Resource Planning (ERP) software.

Managing Data in the Decentralized Environment Permits user departments all over the company to handle some or all of their information systems needs on their own, without having to rely on the central information systems organization. Decentralization is a fact of life to a greater or lesser degree in virtually all companies.

Managing Data in the Decentralized Environment Many people are quite content to develop their own databases on their PCs. However, there is a very strong argument that says that data and database administration are even more important in a decentralized environment than in a centralized one. Most companies have a hybrid centralized/decentralized environment.

The Responsibilities of Data Administration Data coordination. Data planning. Data standards. Liaison to systems analysts and programmers. Training. Arbitration of disputes and usage authorization. Documentation and publicity. Data’s competitive advantage.

Data Coordination In the centralized/decentralized environment, with data and copies of data scattered among mainframe computers, local area network servers, and even PCs, the possibility of inconsistency and error increases. Data coordination becomes the job of the data administrators, by which they maintain a reasonable amount of control over the company’s data.

Data Planning Begins with determining what data will be needed for future company business efforts and the applications that will support them. Related to strategic data planning is the matter of what hardware and software will be needed to support the company’s information systems operations in the future.

Data Standards For example, controlling the way that attribute names, table names, and other data related names are formed. For example, insisting on consistency in the way the programs that access the database are written, especially in regard to the database call instructions.

Liaison to Systems Analysts and Programmers Data administrators are responsible for providing support to the systems analysts and programmers in all matters concerning the data needed by an application. Data analysts are generally involved in database design at some level, but the decision of what that precise level of involvement should be is dependent on a number of factors.

Training Data administration may be responsible for training all those in the company who have a reason to understand the company’s data and, in some cases, the DBMS environment.

Data Ownership Who owns the data? Since data is a resource of value to the company, the data “belongs” to the company’s owners or stockholders. Practically, data is controlled by its user or primary user.

Data Ownership If ownership has been established and a new application requires the use of existing data, then it is the job of data administration to act as an intermediary and approach the owner of the data with the request for data sharing.

Arbitration of Disputes and Usage Authorization If there is a dispute over data sharing, then the data administration group acts as an arbitrator between the disagreeing parties.

Documentation and Publicity The data management function is responsible for documenting the data environment. Documentation includes: a description of the data and the databases, plus programs, reports, and which people have access to these items.

Documentation and Publicity The data management group should perform a publicity function, informing potential users of what data already exists in the database. May help employees discover how to automate more of their work.

Data’s Competitive Advantage Data can provide a competitive advantage for the company. Data administrators are in a unique position to understand how the company “works.”

Data’s Competitive Advantage It is the responsibility of the data administration function to respond to questions about how the company’s business procedures can be adjusted or modified to improve the company’s operating efficiency.

The Responsibilities of Database Administration DBMS performance monitoring. DBMS troubleshooting. DBMS usage and security monitoring. Data dictionary operations. DBMS data and software maintenance. Database design.

Database Performance Monitoring One of the key functions performed by database administration. It is important to know how fast the various applications are executing as part of ensuring that response time requirements are being met.

DBMS Troubleshooting The database administrators should be the troubleshooting interface. Make an assessment of what went wrong and coordinate the appropriate personnel needed to fix it, including systems programmers, application programmers, and the data administrators themselves.

DBMS Usage and Security Monitoring Database administrators keep track of which applications are running in the database environment and can track who is accessing the data in the database at any moment. Security: making sure that only authorized personnel access the data. Usage: the need to maintain records on the amount of use the various users make of the database.

Data Dictionary Operations The database administration group is responsible for the operational aspects, as opposed to the planning aspects, of the data dictionary and any other metadata tools.

DBMS Data and Software Maintenance These activities include: installing new versions of the DBMS installing “fixes” or “patches” to the DBMS performing backup and recovery operations any other tasks related to repairing or upgrading the DBMS or the database.

Database Design There is a wide range in database administration responsibilities for database design. In the centralized environment, database administration is responsible for physical database design and possibly logical database design. In the decentralized environment, database administration role is usually of a consultant.

Data Dictionaries The IS function has been so busy developing and running systems to support all the other corporate functions that it took a long time before it could invest the resources to develop information systems to support itself.

Data Dictionaries Metadata - data about data Data dictionary - a database about data

An Example of Metadata General Hardware Company’s database

A Simple Data Dictionary Metadata stored in the data dictionary database.

Data Dictionary In addition to tracking the basic facts about the represented entities, a data dictionary must keep track of the relationships between the entities.

Data Dictionary Represents the many-to-many relationship between the tables and attributes shown in the data dictionary’s TABLES table and ATTRIBUTES table.

Passive and Active Data Dictionaries Passive Data Dictionary Used for documentation purposes. Data about the entities in the IS environment are entered into the dictionary and cross-referenced as one-to-many and many-to-many relationships. A self-contained database used for documenting the IS environment.

Passive and Active Data Dictionaries Active Data Dictionary Interacts with the IS environment on a real-time basis. Input into the data dictionary Output from the data dictionary

Data Dictionary: Entities and Attributes Data-Related Entities Databases Tables Attributes Web Pages Software-Related Entities Application Programs Database Management Systems Jobs

Data Dictionary: Entities and Attributes Hardware-Related Entities Computers Disks Local-Area Networks Outputs Reports Queries People

Data Dictionary: Relationships Table (or file) Construction: Which attributes (or fields) appear in which tables (or files). Security: Which people have access to which databases or tables or files. Impact of Change: Which programs might be affected by changes to which tables or files. (Note: this has become much less of an issue due to the data independence of relational databases.)

Data Dictionary: Relationships Physical Residence: Which tables or files are on which disks. Program Data Requirements: Which programs use which tables or files. Responsibility: Which people are responsible for updating which databases or tables or files.

Uses and Users The heaviest users of the data dictionary will be IS management and the data administration and database administration functions under them. Systems analysts and program designers can use the data dictionary: as a source of information about what entities, attributes, and so forth already exist in the IS environment. as a documentation device for new information.

Relational DBMS Catalogs A highly active but limited-scope data dictionary that is very closely tied in to the operations of the relational DBMS. Composed of relational tables and may be queried with standard SQL commands.

Relational DBMS Catalogs Database entity data stored includes: Databases Tables Attributes Views Indexes Users Disks

Relational DBMS Catalogs Do not include such entities as reports and nonrelational files. The main purpose of the relational catalog is to accurately support the relational query optimizer. Provides a roadmap through the database data for anyone who wants to query the data or explore new ways to use the data.

Data Repositories A large-scale data dictionary that includes entity types generated and needed by the latest IS technologies. In the CASE environment, the data repository holds the same types of data that traditional data dictionaries hold, as well as CASE-specific data such as reusable code modules.

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