1. Recap of Mar 4: File Organization Major concepts: –Files are made up of records; records are made up of fields –Disk blocks are smaller than files and larger than records; files must be split into disk blocks for storage (and the records in a file must be grouped somehow for storage on disk blocks, independent of the file organization) Fixed-length records Variable length records Block structure: fixed-packed or slotted page File structure: heap, sequential, hashed, or clustered Details of the above file structures

2. Data Dictionary The data dictionary (also called system catalog) stores metadata -- data about data. For example: Information about relations –names of relations –names and types of attributes of each relation –names and definitions of views –integrity constraints User and account information, including passwords

3. Data Dictionary Statistical and descriptive data –number of tuples in each relation Physical file organization information –how relation is stored (sequential, hash, clustered, etc.) –physical location of relation -- operating system file name or disk addresses of blocks containing records of the relation Information about indices –(about which more after the midterm, when we cover chapter 12)

4. Data Dictionary In effect, the data dictionary is a mini database. The data within can either be stored as: –special-purpose data structures and code to access it, or –a set of relations, using the existing database structures and code to access it (most common solution)

5. Data Dictionary Example of a possible system catalog representation: Relation-metadata =(relation-name, number-of-attributes, storage-organization, location) Attribute-metadata =(attribute-name, relation-name, domain-type, position, length) User-metadata =(user-name, encrypted-password, group) Index-metadata =(index-name, relation-name, index-type, index-attributes) View-metadata =(view-name, definition)

6. Reading and Review Upcoming dates: –Mar 11: HW#2 is due –Mar 11 and 13: midterm review –Mar 18: midterm Text Sections we’ve covered: –Chapter 1: Introduction –Chapter 2: E-R data model –Chapter 3 (except 3.4 & 3.5): Relational model –Chapter 4: SQL –Chapter 6: Integrity and Security –Chapter 7 up to and including 7.7: Relational-Database Design –Chapter 11 (except 11.3 and 11.9): Storage and File Structure

7. Reading and Review Chapter 1: Introduction 1.1: Applications and motivation 1.2: Database systems vs. file systems 1.3: Views 1.4: Data models 1.5: Database languages 1.6: Database users and administrators 1.7-1.10: other stuff 1.11: Summary

8. Reading and Review Chapter 2: Entity-Relationship Model 2.1: Basic concepts: entities (entity-sets), relationship (set)s, and attributes 2.2: Constraints and mapping 2.3: Keys 2.4: Design issues 2.5: E-R Diagram 2.6: Weak entity sets 2.7: Extended E-R features (specialization, aggregation) 2.8: Design of an E-R schema 2.9: Reduction of an E-R schema to tables 2.10: (ignore) 2.11: Summary

9. Reading and Review Chapter 3: Relational Model 3.1: Structure of relational databases 3.2: The relational algebra 3.3: Extended relational-algebra operations 3.4, 3.5: (ignore) 3.6: Tuple relational calculus 3.7: Domain relational calculus 3.8: Summary

10. Reading and Review Chapter 4: SQL 4.1: Background 4.2: Basic structure 4.3: Set operations 4.4: Aggregate functions 4.5: Null values 4.6: Nested subqueries 4.7, 4.8: (ignore) 4.9: Modification of the database 4.10: (ignore) 4.11-4.14: (really ignore) 4.15: Summary

11. Reading and Review Chapter 6: Integrity and Security 6.1: Domain Constraints 6.2: Referential Integrity 6.3: Assertions 6.4: Triggers 6.5: Security and Authorization 6.6, 6.7: (ignore) 6.8: Summary

12. Reading and Review Chapter 7: Relational-Database Design 7.1: First Normal Form 7.2: Pitfalls in Relational-Database Design 7.3: Functional Dependencies 7.4: Decomposition 7.5: Desirable Properties of Decomposition 7.6: BCNF 7.7: Third Normal Form 7.8-7.10: (ignore) 7.11: Summary

13. Reading and Review Chapter 11: Storage and File Structure 11.1: Overview of physical storage media 11.2: Magnetic Disks 11.3: RAID (not responsible for this) 11.4: Tertiary Storage 11.5: Storage Access 11.6: File Organization 11.7: Organization of Records in Files 11.8: Data Dictionary Storage 11.9: (ignore) 11.10: Summary