'relational'에 해당되는 글 1

  1. 2011.02.18 Relational Database Fundamentals
 

Relational Database Fundamentals

Education | 2011.02.18 06:31 | Posted by 스마트 안전보건

Relational (Tables) Database Fundamentals
   * Information is everywhere in an organization   
   * Information is stored in databases 
   * Database – maintains information about
      * various types of objects (inventory),
      * events (transactions),
      * people (employees),
      * places (warehouses)   
   * Database models include: 
      * Hierarchical database model 
      * Network database model  
      * Relational database model
         * stores information in the form of logically related two-dimensional tables 

Entities and Attributes
   * Entity – a person, place, thing, transaction, or event about which information is stored 
      * The rows in each table contain the entities 
      * In Figure 6.5 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities   
   * Attribute (field, column) – characteristics or properties of an entity class 
      * The columns in each table contain the attributes 
      * In Figure 6.5 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name

2.jpg 


Keys and Relationships
Primary keys and foreign keys identify the various entities (tables) in the database 
   * Primary key – a field (or group of fields) that uniquely identifies a given entity in a table 
   * Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables 

 

Relational Database Advantages
   * Increased flexibility 
   * Increased scalability and performance 
   * Reduced information redundancy 
   * Increased information integrity (quality) and information security 

 

Relational Database Disadvantages
   * High cost
   * Specialized staff
   * Increased vulnerability

3.jpg

이 글은 스프링노트에서 작성되었습니다.

신고

'Education' 카테고리의 다른 글

2011 Horizon Report (Ed. Tech.)  (0) 2011.02.19
TechTrends journal  (0) 2011.02.19
Relational Database Fundamentals  (0) 2011.02.18
E-business models  (0) 2011.02.18
Educational games  (0) 2011.02.17
This is the results of Shape lecture  (0) 2011.02.15
 

티스토리 툴바