Textbook Notes (369,205)
Canada (162,462)
ITM 100 (123)
Ron Babin (33)
Chapter 7

ITM100 Chapter 7 Notes.docx

3 Pages
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Department
Information Technology Management
Course Code
ITM 100
Professor
Ron Babin

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Chapter 7: Databases and Data Warehouses Data – raw facts that describe the characteristics of an event. Information - data converted into a meaningful and useful context. Granularity refers to the extent of detail within the data and information (fine and detailed vs coarse and abstract) Transactional data – encompasses all of the data contained within a single business process or unit of work, and its primary purpose is to support performing daily operational tasks. Organizations capture and store transactional data in databases and they use it when performing operational tasks and repetitive decisions such as analyzing daily sales figures and production schedules to determine how much inventory to carry. Analytical information – encompasses all organizational information, and its primary purpose is to support the performance of higher level analysis tasks. Real time data- immediate up to date data Real time information – immediate, up to date information Real time system – provides real-time transactional data and/ or real time analytical info in response to query requests Most organizations use real time systems to exploit key corporate transactional data. 5 qualities of data Accuracy Completeness Consistency Uniqueness Timeliness Several issues with low quality data; - Missing data - Incomplete data - Inaccurate data - Duplicates - Wrong - Incomplete data since its invalid Sources of low quality data are; 1. Customers, especially online where they can enter inaccurate data or info to protect their privacy 2. Data or info from different systems having different data or info entry standards and formats 3. Employees entering abbreviated or erroneous data or info by accident or to save time 4. Third party and external data or info that contains inconsistencies, inaccuracies and errors Database- maintains data about various types of objects, events, people and places Hierarchical database model – organized into a tree like structure that allows repeating data using parent/child relationships, in such a way that it cannot have too many relationships. Network database model – flexible way of representing objects and their relationships. Relational database model – type of database that stores data in the form of logically related two dimensional tables. Entity- person, place, thing, transaction or event about which data are stored Entity class – collection of similar entities. Attributes – called fields or columns are characteristics or properties of an entity class. Primary key is a field (or group of fields) that uniquely identifies a given entity in a table Foreign key – relational database model is a primary key of one table that appears as an attribute in another table and acts to provide a logical relationship between the two tables. Relational database + - Increased flexibility - physical view – data deals with the physical storage of data on a storage device such as a hard disk
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