2005 spring csmuintroduction to information management1 organizing data john sum institute of...
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2005 SPRING CSMU Introduction to Information Management
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Organizing Data
John Sum
Institute of Technology Management
National Chung Hsing University
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Data
Data A necessity for almost any enterprise to carry out its business.
Consists of raw facts, and when organized may be transformed into information.
Database A collection of data organized to meet users’ needs
Database Management System (DBMS) A group of programs that manipulate the database and provide
an interface between the database and the user of the database or other application programs.
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CharacterBasic building block of information, represented by a byte.
FieldA group of characters.
RecordA collection of related fields.
TableA collection of related records.
DatabaseA collection of integrated and related tables.
The Hierarchy of Data
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Entity A generalized class of people, places, or things
(objects) for which data is collected, stored, and maintained.
Attribute A characteristics of an entity; something the
entity is identified by. Keys
A field or set of fields in a record that is used to identify the record.
EntitiesCustomer,Employee
AttributesCustomer name, Employee name
Primary keyA field or set of fields that uniquely identifies the record.
Data Entities, Attributes, and Keys
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Key Field Attributes
Entities(records)
Keys and Attributes
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The Traditional Approach
The Traditional ApproachSeparate files
are created and stored for each application program.
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The Database Approach
The Database Approach A pool of related data is shared by multiple
application programs. Rather than having separate data files, each application uses a collection of data that is either joined or related in the database.
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The Database Approach
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Planned Data Redundancy A way of organizing data in which the
logical database design is altered so that certain data entities are combined.
Summary totals are carried in the data records rather than calculated from elemental data.
Some data attributes are repeated in more than one data entity to improve database performance.
Data Modeling and Database Models
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Data Model A map or diagram of entities and their relationships.
Enterprise data modeling Data modeling done at the level of the entire organization.
Entity-Relationship (ER) diagrams A data model that uses basic graphical symbols to show
the organization of and relationships between data.
Data Modeling
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Attributes
Entities
Relationship
Entity Relationship (ER) Diagram
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Hierarchical Database Model A data model in which the data is organized in a top-down,
or inverted tree structure.
Network Data Model An expansion of the hierarchical database model with an
owner-member relationship in which a member may have many owners.
Relational Data Model All data elements are placed in two-dimensional tables,
called relations, that are the logical equivalent of files.
Database Models
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Hierarchical Database Model
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A Network Data Model
Members
Owners
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A Relational Data Model
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Relational Database Terms
Selecting Data manipulation that eliminates rows according to
certain criteria.
Projecting Data manipulation that eliminates columns in a table.
Joining Data manipulation that combines two or more tables.
Linked Related tables in a relational database together.
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Description Dept. Number Manager SSN Lastname HiredateSales Manual 598 098-40-1370 Fiske 01-05-1985
Linking Data Tables to Answer an Inquiry
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Logical Access Path
Application requires information from the DBMS.
Physical Access Path
DBMS accesses a storage device to retrieve data.
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Logical and Physical Access Paths
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Concurrency Control A method of dealing with a situation in which two or more
people need to access the same record in a database at the same time.
Data Manipulation Language (DML) The commands that are used to manipulate the data in a
database.
Structured Query Language (SQL) A standardized data manipulation language.
Manipulating Data
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Structured Query Language
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Database Output
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Microsoft Access Lotus Approach Orcale IBM DB2
DBMS Selection Criteria
Database size
Number of concurrent users
Performance
Integration
Features
The vendor
Cost
Popular DBMS
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Distributed Databases
A database in which the actual data may be spread across several smaller databases connected via telecommunications devices.
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Distributed Databases
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Open Database Connectivity (ODBC) A set of standards that
ensures software written to comply with these standards can be used with any ODBC-compliant database.
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The automated discovery of patterns and relationships in a data warehouse.
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Data Mining