* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 4
Survey
Document related concepts
Global serializability wikipedia , lookup
Commitment ordering wikipedia , lookup
Microsoft SQL Server wikipedia , lookup
Serializability wikipedia , lookup
Microsoft Access wikipedia , lookup
Entity–attribute–value model wikipedia , lookup
Open Database Connectivity wikipedia , lookup
Extensible Storage Engine wikipedia , lookup
Oracle Database wikipedia , lookup
Ingres (database) wikipedia , lookup
Microsoft Jet Database Engine wikipedia , lookup
Functional Database Model wikipedia , lookup
Concurrency control wikipedia , lookup
Relational model wikipedia , lookup
Clusterpoint wikipedia , lookup
Transcript
Chapter 4 Database Processing Agenda • • • • • • • • • Purpose of Database Terminology Components of Database System Multi-user Processing Database Design Entity-relationship Model Database Administration Database Security Discussion, Design, and Case Study Purpose of Database • to keep track of things that involve more than one theme Terminology - I • Database – A collection of self-describing and integrated records • The hierarchy of data elements – Bytes – columns – fields – rows (records) – tables (files or relations) – database • Database – A collection of tables plus relationships (in terms of) among rows (records) in these tables • Relationships – Primary key: a column or group of columns to identify a unique row in a table – Foreign key: a non-key column or field in one table that links to a primary key in another table Hierarchy of Data Elements Examples of Relationships Among Rows Terminology - II • Relational database – Tables – Relationship using primary key and foreign key • Metadata – The structure of the database – The data describe the data • Field name, data type, description, property Metadata Example (in Access) Components of a Database Components of Database System • Database management system (DBMS): software – To create tables, relationships, and other structure – To process (read, insert, modify, or delete) data – To produce forms, reports, and queries through database application – To administer (security, back up, recover, clean up, and enhance performance) a database • Structured Query Language (SQL) – An international standard language for processing a database • Product types – Enterprise DBMS: IBM (DB2), Microsoft (SQL Server), Oracle Corporation (Oracle), Open-source (MySQL) – Personnel DBMS: Microsoft (Access) for 15 or less users Components of a Database Application System Use of Multiple Database Applications Four Application Programs on Web Server Computer Multi-user Processing • More than one user accessing a particular database table at same time • Lost-update problem • Lock Database Design • Create data model – Logical representation of database based on users view on the business environment (user’s requirements) – Data and relationships that users want to track • Create database design – The process of converting a data model into tables, relationships, and data constraints – Normalization: the process of converting poorly structured tables into two or more well-structured tables to avoid data integrity problems • Users’ reveiw • Create database Entity Relationship Model - I • Components – – – – Entity: physical object (rectangular) Attributes: characteristics of the entity Primary key: identifier Relationship: primary key and foreign key (line) • Normalization – The process of converting poorly structured tables into two or more well-structured tables – Every table describe a single topic or theme – To avoid data integrity problems – To avoid generating incorrect and inconsistent information – Trade off between performance – Normal form Entity Relationship Model - II • Entity-relationship diagram – Entity: rectangular – Relationship: line • • • • One-to-one: 1:1 One-to-many (crow’s foot): 1:N Many-to-many: N:M Many-to-many relationship has to be changed to two 1:N relationship via an intersection table • Maximum cardinality • Minimum cardinality Database Development Process Example Relationships Showing Minimum Cardinalities Transforming a Data Model into a Database Design Representing a 1:N Relationship - I Representing a 1:N Relationship - II Representing a N:M Relationship Database Administration - I • Functions – Manage the development, operation, and maintenance of a database to achieve the organization’s objectives – Balance conflicting goals to protect the database and maximize its availability for authorized use • DBA – Database administrator or office of database administration – an auditor, a consultant, sometimes a policeman, and a diplomat working as a liaison between the users and professional developers Database Administration - II • DBA responsibilities – – – – – Database development Database operation Backup and recovery Adopt new database change requirements Create a steering committee consisting of key users • Steering committee – Community-wide decisions regarding the development, use, and maintenance of the database – Community-wide policies for the processing of the database – Processing rights (minimum) Database Security • • • • Firewall OS and DBMS patches Physical access security User accounts, roles, and minimum permission • Processing and error logs • Security emergency plan Discussion • Ethics (81a-b) – What should the company do to avoid the situation at first place? – What should the company do to properly handle Kelly’s case – What should Kelly do to avoid the stated consequence after querying the database? – What could Kelly do to save his career? • Opposing forces (97a-b) – What should the DBA of car dealer do to convince every salesperson to build and use a solid sales information database? • Reflections (101a-b) – What should the DBA of any organization to handle the changing requirements for a new database? – What should the DBA of any organization to handle the new requirements for a existing database? Relational Database Design • Given the following entities and their attributes – – – – – Buyer (BuyerID, BuyerName) Owner (OwnerID, OwnerName) Property (PropertyID, PropertyAddres, OwnerID) Agent (AgentID, AgentName) Sales (SalesID, BuyerID, OwnerID, PropertyID, AgentID, Price, Date) • Design a relational database – Create primary key for every entity and the necessary foreign key – Create an entity-relationship diagram Case Study • Assignment 22 (105) • Case 4-1 (107-110): questions 1, 4, and 7 (add aircraft for 7) • Case 4-2 (110-113): questions 1 and 2 Points to Remember • • • • • • • • • Purpose of Database Terminology Components of Database System Multi-user Processing Database Design Entity-relationship Model Database Administration Database Security Discussion, Design, and Case Study