Modern Database Management
MODERN DATABASE MANAGEMENT
- Database o An organized collection of logically related data. o May be any size and complexity.
- Data o A stored representation of objects and events that have meaning and importance in the user’s environment. o Become useful when placed in some sort of context. o Structured
• Facts such as the customer name, address, and telephone number.
• The most important structured data types are numeric, character, and dates.
• Stored in tabular form
• Found in traditional database. o Data are often preprocessed and stored in summarized form in databases that are used for decision support.
- Data vs. Information o Information – data that have been processed in such a way that the knowledge of the person who uses the data is increased.
• May be data to some and information to others.
• A way to convert data into information is to summarize them or otherwise process and present them for human interpretation.
- Metadata o Data that describe the properties or characteristics of end-user data and the context of that data.
• Some of the properties described include data names, definitions, length (or size), and allowable values.
• Include the source of the data, where the data are stored, ownership (or stewardship), and usage.
• “Data about data”
- Traditional File Processing Systems o Built at the time when there were no databases. o Useful for business applications o Computers had to store, manipulate, and retrieve large files of data. o The basic structure and purpose have changed little over several decades. o Often there is duplication of some of the files used by multiple applications.
- Disadvantages of File Processing Systems o Program-data dependence
• File descriptions are stored within each database application program that accesses a given file.
• Would have to change updated file descriptions in every application that accesses that files.
• Very timely
• Could cause errors when
- Database o An organized collection of logically related data. o May be any size and complexity.
- Data o A stored representation of objects and events that have meaning and importance in the user’s environment. o Become useful when placed in some sort of context. o Structured
• Facts such as the customer name, address, and telephone number.
• The most important structured data types are numeric, character, and dates.
• Stored in tabular form
• Found in traditional database. o Data are often preprocessed and stored in summarized form in databases that are used for decision support.
- Data vs. Information o Information – data that have been processed in such a way that the knowledge of the person who uses the data is increased.
• May be data to some and information to others.
• A way to convert data into information is to summarize them or otherwise process and present them for human interpretation.
- Metadata o Data that describe the properties or characteristics of end-user data and the context of that data.
• Some of the properties described include data names, definitions, length (or size), and allowable values.
• Include the source of the data, where the data are stored, ownership (or stewardship), and usage.
• “Data about data”
- Traditional File Processing Systems o Built at the time when there were no databases. o Useful for business applications o Computers had to store, manipulate, and retrieve large files of data. o The basic structure and purpose have changed little over several decades. o Often there is duplication of some of the files used by multiple applications.
- Disadvantages of File Processing Systems o Program-data dependence
• File descriptions are stored within each database application program that accesses a given file.
• Would have to change updated file descriptions in every application that accesses that files.
• Very timely
• Could cause errors when