1 / 10

File and Database Design

File and Database Design. Class 22. File and database design:. 1. Choosing the storage format for each attribute from the logical data model. 2. Grouping attributes from the logical data model into physical records.

aira
Download Presentation

File and Database Design

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. File and Database Design Class 22

  2. File and database design: • 1. Choosing the storage format for each attribute from the logical data model. • 2. Grouping attributes from the logical data model into physical records. • 3. Arranging related records in secondary memory so that individual and groups of records can be sorted, retrieved, and updated rapidly. • 4. Selecting media and structures for storing data to make access more efficient.

  3. What we’re looking at • Fields, Records, Files, Databases

  4. Fields • Name • Data type • Primary key(s) • Data Integrity • Handling missing data • Ownership

  5. Data Integrity • Default Value • Picture Control • Range Controls • Referential Integrity • Null Value Control

  6. Records • A group of fields stored in adjacent memory locations and retrieved together as a unit. • Denormalization (which you’ll learn in the Database class) will be done on records.

  7. Files • Different types of files: • Master File • Look-up Table file • Transaction file • Audit Trail • History files

  8. 2 File Organization Types • Sequential • Indexed

  9. What to consider in choosing file organization • Fast data retrieval • Efficient use of storage space • Protection from failures or data loss • Accommodating growth • Security from unauthorized use

  10. Designing a relational database • Create a table (file) for each entity type. • Choose a primary key for each table. • Create new tables to represent many-to-many relationships. • Add foreign keys to represent one-to-many relationships. • Define referential integrity constraints. • Evaluate schema quality and make necessary improvements. • Choose appropriate data types and value restrictions for each field.

More Related