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Managing Data Resources. Chapter 7. Data hierarchy. Bit Byte Field Record File Database – a group of related files. Basic data concepts. An entity is a person, place, thing or event on which we maintain information, for example, a student record
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Managing Data Resources Chapter 7
Data hierarchy • Bit • Byte • Field • Record • File • Database – a group of related files
Basic data concepts • An entity is a person, place, thing or event on which we maintain information, for example, a student record • An attribute is a field describing a characteristic or quality of an entity, for example, student name • A key field is an identifier field
Traditional File Environment • Manually create several different data management programs • As compared with modern database management systems, traditional file environment has many problems.
Problems with the traditional file environment • Data redundancy and confusion • Program-data dependence • Lack of flexibility • Poor security • Lack of data-sharing and availability
The database environment • Avoid problems happened in the traditional file environment • A single database serves multiple applications and also easily allow users to draw together all the information for other applications • The database management system acts as the interface between the application programs and the data • But is much more expensive and need professional management • Can rent it through application software providers (ASP)
Components of a DBMS • A data definition language • A data manipulation language • A data dictionary
A data definition language • Is used to specify the content and structure of the database • Define each data element
A data manipulation language • Is used to manipulate data in the database for some application through some application software • Structured query language, or SQL, is a famous data manipulation language
Data dictionary • An automated or manual file that stores definition of data elements and data characteristics such as usage, physical representation, ownership, authorization and security
Database trends • OLAP vs. OLTP – On line transaction processing does not analyze data using multidimensional data analysis called on line analytical processing • Data warehouses are databases that store current and historical data of potential interest to managers throughout the company
Benefits of data warehouses • Improved information • Easy access • The ability to model and remodel the data in the warehouse • Uses OLAP and datamining to help refocus businesses
Linking internal DB to the web • Legacy system • Middle ware • SQL • Application server customer program • Internet • Web browser
Key organizational elements in the database environment • Data administration • Data planning and modeling methodology • Database technology and management • users
Data administration • Data as an organizational resource • Administration means to develop information policy, to plan for data including overseeing database design and monitoring how information system specialists and end-users use data • The head of it is called CIO
Database administration • Define and organize database structure and content • Develop security procedures to safeguard the database • Develop database documentation • Maintains the database management software