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File and Database Design

This class examines the essential strategies for effective file and database design. It covers selecting the appropriate storage formats for attributes based on logical data models, grouping attributes into physical records, and arranging records in secondary memory for fast access and updates. Participants will learn to understand fields, records, files, and databases, focusing on critical concepts such as data types, primary keys, data integrity, and referential integrity. Additionally, the course covers file organization types, denormalization, and designing relational databases to ensure efficient data retrieval and security.

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File and Database Design

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  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.

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