1. ©Silberschatz, Korth and Sudarshan1.1Database System Concepts COMP319: Introduction Course Structure Course Assessment Review: DBMS Structure Review: Terminology (schema, instance…) Review: The Relational Model and SQL Review: DDL, DML Review: Transaction Management Database Users and Administrator Coordinator: Dr Mark Utting, marku@cs.waikato.ac.nzmarku@cs.waikato.ac.nz Tutor: Andrew Revel, adr3@cs.waikato.ac.nzadr3@cs.waikato.ac.nz Lecturers: Dr Mark Utting and Dr Wilhelm Steinbuss Web Site: http://www.cs.waikato.ac.nz/Teaching/COMP319Bhttp://www.cs.waikato.ac.nz/Teaching/COMP319B Textbook: Database System Concepts, Silberschatz, 4 th Ed.

2. ©Silberschatz, Korth and Sudarshan1.2Database System Concepts COMP319 Course Structure Weeks 1-2: Relational DMLs  Relational Algebra/Calculus; [Chap. 3]  Advanced SQL [Chap 4] Weeks 2-6: DBMS Implementation  Disk and file structures; [Chap 11]  Indices; [Chap 12]  SQL implementation and Optimization. [Chap 13-14] Weeks 7-12: Advanced Database Design and Management  Database design via Entity-Relationship Diagrams  Sybase Power designer tool  Normal Forms up to 3NF and BCNF  Transaction Management: isolation levels; restart/recovery mechanisms; backup strategies  Security concepts

3. ©Silberschatz, Korth and Sudarshan1.3Database System Concepts COMP319 Assessment Assignments (10% each) 1. Relational Algebra/Calculus [Due: Fri 8 Aug Week 4] 2. SQL implementation and optimization [Due: Fri 12 Sep, Week 7] 3. Steinbuss 1 [Due: Fri 3 Oct, Week 10] 4. Steinbuss 2 [Due: Fri 24 Oct, Study Week] Mid Semester Test (10%) Exam (50%)

4. ©Silberschatz, Korth and Sudarshan1.4Database System Concepts Overall DBMS System Structure

5. ©Silberschatz, Korth and Sudarshan1.5Database System Concepts Instances and Schemas Similar to types and variables in programming languages Schema – the logical structure of the database  e.g., the database consists of information about a set of customers and accounts and the relationship between them)  Analogous to type information of a variable in a program  Physical schema: database design at the physical level  Logical schema: database design at the logical level Instance – the actual content of the database at a particular point in time  Analogous to the value of a variable Physical Data Independence – the ability to modify the physical schema without changing the logical schema  Applications depend on the logical schema  In general, the interfaces between the various levels and components should be well defined so that changes in some parts do not seriously influence others.

6. ©Silberschatz, Korth and Sudarshan1.6Database System Concepts A Sample Relational Database

7. ©Silberschatz, Korth and Sudarshan1.7Database System Concepts Data Definition Language (DDL) Specification notation for defining the database schema  E.g. create table account ( account-number char(10), balance integer) DDL compiler generates a set of tables stored in a data dictionary Data dictionary contains metadata (i.e., data about data)  database schema  Data storage and definition language  language in which the storage structure and access methods used by the database system are specified  Usually an extension of the data definition language

8. ©Silberschatz, Korth and Sudarshan1.8Database System Concepts Data Manipulation Language (DML) Language for accessing and manipulating the data organized by the appropriate data model  DML also known as query language Two classes of languages  Procedural – user specifies what data is required and how to get those data (Example: Relational Algebra)  Nonprocedural – user specifies what data is required without specifying how to get It (Example: Tuple Calculus) SQL is the most widely used query language  E.g.select customer.customer-name from customer where customer.customer-id = ‘192-83-7465’  Application Programs also use SQL: embedded SQL or via ODBC/JDBC  Find: all Rye customers with account balances > $700.

9. ©Silberschatz, Korth and Sudarshan1.9Database System Concepts Transaction Management A transaction is a collection of operations that performs a single logical function in a database application Transaction-management component ensures that the database remains in a consistent (correct) state despite system failures (e.g., power failures and operating system crashes) and transaction failures. Concurrency-control manager controls the interaction among the concurrent transactions, to ensure the consistency of the database.

10. ©Silberschatz, Korth and Sudarshan1.10Database System Concepts Database Users Users are differentiated by the way they expect to interact with the system Naive users – invoke one of the permanent application programs that have been written previously  E.g. people accessing database over the web, bank tellers, clerical staff Application programmers – interact with system through DML calls (e.g., ODBC/JDBC). Sophisticated users – write requests in a database query language like SQL Specialized users – write specialized database applications that do not fit into the traditional data processing framework Database Administrator...

11. ©Silberschatz, Korth and Sudarshan1.11Database System Concepts Database Administrator Coordinates all the activities of the database system; the database administrator has a good understanding of the enterprise’s information resources and needs. Database administrator's duties include:  Schema definition  Storage structure and access method definition  Schema and physical organization modification  Granting user authority to access the database  Specifying integrity constraints  Acting as liaison with users  Monitoring performance and responding to changes in requirements