DATA RESOURCE MANAGEMENT
Dzulfikar Muhammad A.
Computer science
Semester 2
Character. The most basic logical element is the character, which consists of a single alphabetic, numeric, or other symbol. While it may take several bits or bytes to represent a character digitally, remember that these refer to physical storage, not the logical concept of the character itself.
Field. A field is a grouping of characters that represent a characteristic of a person, place, thing, or event. A person's name is typically placed in a field. A field is a data item. A data field represents an attribute or some entity.
Record. A record is a collection of interrelated fields. For example, an
employee's payroll record usually contains several fields, such as their name, social security number, department, and salary. Records may be fixeddlength or variabledlength.
File. A file is a collection of interrelated records. For example, a payroll file might contain all of the payroll files for all the employees of a firm. Files are usually classified by the application for which they are used.
Database. A database is an integrated collection of logically interrelated records or files. For example, the personnel database of a firm might contain payroll, personnel action, and employee skills files. The data stored in a database is independent of the application programs using it and of the type of secondary storage devices on which it is stored.
Under the database management approach, data records are consolidated into databases that can be accessed by many diferent application programs. A database management system (DBMS) is a set of computer programs that control the creation, maintenance, and use of the databases of an organization and its end users. Four major DBMS facilities include:
Database Development. A DBMS allows control of development to be placed with database administrators. The administrator uses a data definition language (DDL) to develop and specify the data contents, relationships, and structure of each database, and to modify these specifications when necessary. This
approach improves integrity and security for the organizational databases. The information is stored in a data dictionary, which uses data definitions to specify what all the records and files are, can be, and, if desired, to automatically enforce data element definitions when fields, records, or files are modified.
Database Interrogation. A DBMS allows end users without programming skills to ask for information from a database using a query language or report generator. Queries are usually made one of two ways:
SQL (Structured Query Language). This uses the basic form of
QBE (Query by Example). This method allows users to point and click on display boxes for each of the data fields in one or more files to specify the rules of the search
Database Maintenance. Updating the databases and other maintenance are conducted by transaction processing programs.
Application Development. A DBMS makes application development much easier and quicker by allowing developers to include data manipulation language (DML) statements in their programs that let the DBMS perform necessary datadhandling activities.
Six major types of databases are illustrated on the slide and used by computerd based organizations:
Operational Databases. These databases store detailed data needed to support the operations of the entire organization. They are also called subject area databases (SADB), transaction databases, and production databases. These also include databases of Internet and electronic commerce activity, such as click stream data or data describing online behavior of visitors at a company’s website.
Data Warehouse Databases. These store data from current and previous years that has been extracted from the various operational and management
databases of the organization. As a standardized and integrated central source of data, warehouses can be used by managers for pattern processing, where key factors and trends about operations can be identified from the historical record. Data Marts. Are subsets of the data included in a Data Warehouse which focus on specific aspects of a company, e.g. department, business process, etc. Distributed Databases. These are the databases of local workgroups and departments at regional ofces, branch ofces, and other work sites needed to complete the task at hand. They include relevant information from other
organizational databases combined with data and information generated only at the particular site. These databases can reside on network servers, on the World Wide Web, or on Intranets and Extranets.
End User Databases. These consist of a variety of data files developed by end users at their workstations. For example, an end user in sales might combine information on a customer’s order history with her own notes and impressions from facedtodface meetings to improve followdup.
A data warehouse stores data that has been extracted from various operational, external, and other databases within the organization.
To create a data warehouse, data from various databases are captured, cleaned, e.g. sorted, filtered, converted, and transformed into data that can be better used for analysis. The data is then stored in the enterprise data warehouse, from where it can be moved into data marts or to an analytical data store that holds data to support certain types of analysis.
Metadata, that defines the data in the data warehouse, is stored in a Metadata Directory that is used to support data administration. A variety of analytical software tools can then be used to query, report, and analyze data.
One such means for analyzing data in a data warehouse is called data mining. In data mining, the data in a data warehouse are analyzed to reveal hidden patterns and trends in historical business activity. This can help managers make decisions about strategic changes in business operations.
The rapid growth of websites on the Internet and corporate intranets and extranets has dramatically increased the use of databases of hypertext and hypermedia documents.
Hypermedia Database: A website stores information in a hypermedia database consisting of a home page and other hyperlinked pages of multimedia or mixed media (text, graphics and photographic images, video clips, audio segments, and so on).
Browser: A web browser on your client PC is used to connect with a web network server. This server runs web software to access and transfer the web pages you request.
Web Site: A website uses a hypermedia database consisting of HTML (Hypertext Markup Language) pages, GIF (graphics image files) files, and video files.
Web Server Software: Acts as a database management system to manage the use of the interrelated hypermedia pages of the website.
The security and integrity of an organization's databases are the major concerns of the data resource management eforts. Key activities of data resource
management include:
Database Administration. This area is responsible for developing and maintaining the organization's data dictionary, as well as designing and monitoring the performance of databases, and enforcing the standards for database use and security.
Data Administration. This area involves the establishment and enforcement of policies and procedures for managing data as a strategic corporate resource. This means standardizing data so that it is available to all end users from whatever database they are working.
The relationships among the records stored in databases are based upon one of several logical database structures or models. These fundamental database structures are described below.
Hierarchical Structure. Under this treedlike structure, each data element is related only to one element above it, a sodcalled onedtodmany relationship. All records are dependent and arranged in multilevel structures.
Network Structure. This structure features a manydtodmany arrangement
whereby the DBMS can access a data element by following one of several paths. Relational Structure. This model has become the most popular structure and is used by most microcomputers. All data elements within the database are viewed as being stored in the form of simple tables. The DBMS can link data elements from various tables to provide information to end users.
ObjectdOriented Structure. Objects consist of data values describing the attributes of an entity and the operations that can be performed on the data. This is called encapsulation and allows objectdoriented database structures to better handle complex types of data such as video and audio. The objectd
oriented model also supports inheritance, allowing new objects to replicate some or all the characteristics of one or more parent objects, as shown in the slide. Such capabilities allow developers to copy and combine objects, allowing for very rapid development of new database solutions.
Multidimensional Structure. This structure uses cells within a multidimensional framework to aggregate data related to elements within a given dimension. Each cell combines with similar cells to form a coherent "cube" of information and data, which in turn is combined with other cubes to form dimensions. As a result they are both compact and easy to understand. Multidimensional
structures have fast become the most popular database structure for analytical databases that support online analytical processing (OLAP) applications.
Efcient access to data is the critical necessity of an efective database system. Key concepts and terms associated with file access include:
Key Fields. This is a unique identifier of the data record.
URLs. The files and databases on the Internet and corporate intranets and extranets use URLs (Uniform Resource Locators) for data access. Thus, pages of hyperlinked text and multimedia documents on the Web and intranet/extranet websites are accessed by URLs.
Sequential Access. This refers to the predetermined order of processing data. Each record is accessed according to the same set of commands. Access begins at the start of the file or record and proceeds, in order, to the end. This is a fast and efcient method for processing large volumes of data.
Direct Access. Under this method, records do not have to be arranged into any particular sequence on storage media, however the computer must keep track of the storage location of each record.
Key Transformation. This common direct access technique performs an
arithmetic computation on a key field or record and uses the number that results as an address to store and access that record.
Indexed Sequential Access Method. This approach combines features of both sequential and direct access. Sequential storage allows for large volume
processing while indexed addressing allows direct access of smaller amounts of data from individual records.
Database planning, beyond that of a personal or small business end user
database created by a database management package, typically requires use of a topddown data planning process based upon the systems development model covered earlier:
1. Data Planning. At this stage, planners develop a model of business processes. This results in an enterprise model of business processes with documentation.
2. Requirements Specification. This stage defines the information needs of end users in a business process. Description of needs may be provided in natural language or using the tools of a particular design methodology.
3. Conceptual Design. This stage expresses all information requirements in the form of a highdlevel model.
4. Logical Design. This stage translates the conceptual model into the data model of a DBMS.
5. Physical Design. This stage determines the data storage structures and access methods.
Data resource management is a critical management activity. Management roles include database administration, data planning, and data administration. Under the database management approach, data records are consolidated into databases that can be accessed by many diferent application programs, serving multiple users.
