©Silberschatz, Korth and Sudarshan1.1Database System Concepts COMP319: Introduction Course...
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Transcript of ©Silberschatz, Korth and Sudarshan1.1Database System Concepts COMP319: Introduction Course...
©Silberschatz, Korth and Sudarshan1.1Database System Concepts
COMP319: IntroductionCOMP319: 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, [email protected]
Tutor: Andrew Revel, [email protected]
Lecturers: Dr Mark Utting and Dr Wilhelm Steinbuss
Web Site: http://www.cs.waikato.ac.nz/Teaching/COMP319B
Textbook: Database System Concepts, Silberschatz, 4th Ed.
©Silberschatz, Korth and Sudarshan1.2Database System Concepts
COMP319 Course StructureCOMP319 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
©Silberschatz, Korth and Sudarshan1.3Database System Concepts
COMP319 AssessmentCOMP319 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%)
©Silberschatz, Korth and Sudarshan1.4Database System Concepts
Overall DBMS System Structure Overall DBMS System Structure
©Silberschatz, Korth and Sudarshan1.5Database System Concepts
Instances and SchemasInstances 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.
©Silberschatz, Korth and Sudarshan1.6Database System Concepts
A Sample Relational DatabaseA Sample Relational Database
©Silberschatz, Korth and Sudarshan1.7Database System Concepts
Data Definition Language (DDL)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
©Silberschatz, Korth and Sudarshan1.8Database System Concepts
Data Manipulation Language (DML)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 customerwhere 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.
©Silberschatz, Korth and Sudarshan1.9Database System Concepts
Transaction ManagementTransaction 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.
©Silberschatz, Korth and Sudarshan1.10Database System Concepts
Database UsersDatabase 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 . . .
©Silberschatz, Korth and Sudarshan1.11Database System Concepts
Database AdministratorDatabase 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