Relation DB Model

Relation DB Model

1. Structure

   • Relation
     • Rows
     • Columns
     • Properties
       • No duplicate tuples
       • Sequential of Tuples not have important
       • Each Attribute can keep only one value
     • Kind of Relation
       • Base Relation
         • A relation that defined to keep data and bring it to use when create relation with ' Data Dictionary ' like SQL command such as CREATE TABLE 
         • A relation that defined to keep data and bring it to use when create relation with ' Data Dictionary ' like SQL command such as CREATE TABLE
       • View of Virtual Relation
         • A relation that created by each user . Cause each user wants different data . So create ' View ' for convenience to use and keep security 
         • A relation that created by each user . Cause each user wants different data . So create ' View ' for convenience to use and keep security
     • Domain
       • Defining range and data's type to prevent from typing mistake into relation
     • Tuple
       • Data in each relation . Might insert, modify, delete
     • KEY
       • Primary Key
       • Foreign Key
       • Alternate Key / Secondary Key
       • Simple Key
       • Combine Key / Composite Key