Logical and Physical Database Organizations

Logical and Physical Database Organizations

1. Sequential File Organization

   • Organización secuencial Índice
     • The indices are generated and included as sequential index file is organized and stored.
       • Primary Index
       • Secondary Index

2. Random File Organization

   • Hashed Keys
   • Rehashing
   • Collision
     • Open Address method
     • External chaining
     • Coalesced chaining

3. Other Organizations and Access Methods

   • Choice of File Organization and Access Methods
     • The factors affecting choice includes
       • Security and Backup
       • Hit Rate
       • Size
       • .Reference and Enquiry

4. Other Types of Storage Methods

   • The main types of storage are
     • Serial-access storage (SAS
     • Immediate-access storage (IAS)
     • Direct-access storage (DAS)

5. File Calculations

   • Two basic types of calculation are often needed when using files
     • The storage space occupied by the file
     • The time taken to read or write the file