databases3 - Database Management A GIS can answer the...

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Database Management
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A GIS can answer the question: What is where? WHAT: Characteristics of attributes  or features WHERE:   In geographic space Often a “more involved” retrieval Attribute query Spatial query
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Need some way of organizing data That supports access and update Think about finding a book in a library  or a “contact” in your cell phone’s  contacts list 
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A simple way of thinking about organizing information. Locational information, but no coordinates, however.
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Data Organization Data Item Basic building block of a database Occurrence or instance of a particular  characteristic  pertaining to a given  entity In DB terminology, a data item is often called an ‘ attribute ’  or a ‘stored  field The values can be numeric, string, boolean, time, etc.
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Data Organization A set of attributes are used to represent the state of  real-world features (e.g., a row in an ArcGIS table) E.g. all the attributes of an employee - employee id,  department, salary, level, etc. All attributes of a road segment Formally referred to as a ‘tuple’ in RDBMS  (sometimes referred to as a record)
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Data Organization Data File A grouping of related records/tuples ‘Related records’ means that it represents different  occurrences  of the same class of entities E.g. a data file containing information of all the  employees of a particular company, roads in a county
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Data Organization Databases Higher level of data organization- multiple related data files Databases can be managed in several ways - a DBMS (R-DBMS)  are commonly used today More about this later…
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Given me a spatial example of: Entities Attributes about the entities Records/tuples Data files Databases
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We can begin to accumulate several instances of a common type of information. Not unlike telephone directories (info about phone numbers) or a library database (info about books) or set of roads or hotels
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Flat File  Database Record Value Value Value Attribute Attribute Attribute Record Value Value Value Record Value Value Value
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Basic structure of flat file. Historically, the structure has been relatively “rigid
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This note was uploaded on 04/01/2012 for the course 044 005 taught by Professor Davidbennett during the Fall '11 term at University of Iowa.

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databases3 - Database Management A GIS can answer the...

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