Database Management Review
Chapter 1: Database Systems
Summary
• Data are raw facts. Information is the result of processing data to reveal their meaning. Accurate, relavant and timely information is the key to good decision making and good decision making is the key to organizational survival in a global environment
• Data are usually stored in a database. To implement a database and manage its contents you need a database management system (DBMS). DBMS serves as an intermediary between the user and the database. The database contains the data you have collected & “data about data” metadata.
• Database design defines the database structure. A well-designed database facilitates data management and generates accurate and valuable information. A poorly designed database can lead to bad decision making and bad decision making can lead to the failure of an organization.
• Databases can be classified according to the number of users supported, where the data are located, the type of data stored, the intended data usage and the degree to which the data are structured.
• Databases evolved from manual and then computerized file systems. In a file system, data are stored in independent files, each requiring its own data management programs. Although this method of data management is largely out-moded, understanding its characteristics makes database design easier to comprehend.
• Some limitations of file system data management are that it requires extensive programming, system administration can be complex and difficult, making changes to existing structures is difficult and security features are likely to be inadequate. Also, independent files tend to contain redundant data, leading to problems of structural and data dependence.
• Database management systems were developed to address the file system’s inherent weaknesses. Rather than depositing data in independent files, a DBMS presents the database to the end user as a single
Summary
• Data are raw facts. Information is the result of processing data to reveal their meaning. Accurate, relavant and timely information is the key to good decision making and good decision making is the key to organizational survival in a global environment
• Data are usually stored in a database. To implement a database and manage its contents you need a database management system (DBMS). DBMS serves as an intermediary between the user and the database. The database contains the data you have collected & “data about data” metadata.
• Database design defines the database structure. A well-designed database facilitates data management and generates accurate and valuable information. A poorly designed database can lead to bad decision making and bad decision making can lead to the failure of an organization.
• Databases can be classified according to the number of users supported, where the data are located, the type of data stored, the intended data usage and the degree to which the data are structured.
• Databases evolved from manual and then computerized file systems. In a file system, data are stored in independent files, each requiring its own data management programs. Although this method of data management is largely out-moded, understanding its characteristics makes database design easier to comprehend.
• Some limitations of file system data management are that it requires extensive programming, system administration can be complex and difficult, making changes to existing structures is difficult and security features are likely to be inadequate. Also, independent files tend to contain redundant data, leading to problems of structural and data dependence.
• Database management systems were developed to address the file system’s inherent weaknesses. Rather than depositing data in independent files, a DBMS presents the database to the end user as a single