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Chapter 3 Database Management 1 2 Chapter 3 Objectives Understand why databases are important to modern organizations Understand how databases work Understand how organizations can maximize their strategic potential with databases 3 Database Management for Strategic Advantage Database – a collection of related data organized in a way to facilitate data searches Use databases to: – – – – Create a book Track book sales Set salaries and wages Pay employees 4 Database Management for Strategic Advantage The Database Approach: Foundational Concepts – DBMS – Database Management Systems – Use a DBMS software to create, store, organize, and retrieve data from a single database or several databases – Example: Microsoft Access 5 Database Management for Strategic Advantage Advantages of the Database Approach – – – – – – – – – Program-data independence Minimal data redundancy Improved data consistency Improved data sharing Increased productivity of application development Enforcement of standards Improved data quality Improved data accessibility Reduced program maintenance 6 Database Management for Strategic Advantage Effective Management of Databases – The database administrator (DBA) : • Works with programmers and analysts to design and implement the database • Works with users and managers to establish database policies • Implements security features and establishes database permissions 7 Key Database Activities Entering and Querying Data – Form – Structured Query Language (SQL) – Query by example (QBE) 8 Key Database Activities Creating Database Reports – Report – a compilation of data that is organized and produced in printed format – Report Generators 9 Key Database Activities Database Design – – – – Must be organized Few or no redundancies Data model – a map of entity relationships Keys • Primary key • Combination primary key • Secondary key 10 11 Key Database Activities Database Associations – One-to-one (teams to stadiums) – One-to-many (player to team) – Many-to-many (players to games) 12 Key Database Activities Entity-Relationship Diagramming (ERD) – Commonly used when designing databases – One draws entities (tables) as boxes and lines between entities to show relationships 13 Key Database Activities The Relational Model of Databases – Entities linked by a common key field • Records = rows • Fields = columns – Other models exist • Hierarchical • Network • Object-oriented model 14 Key Database Activities Normalization – A technique for making complex databases more efficient and more easily handled by the DBMS – Eliminates data redundancy 15 16 17 Key Database Activities Data Dictionary – A document that explains each piece of information in the database • Field name • Data type – Numeric, text, date/time – Useful for sorting and allocating storage • Is this field a key field? • Business rules – Update authority – Valid data values 18 How Organizations Get the Most from Their Data Linking Web Sites to Databases – Example: Amazon • 2.5 million titles • Managing online data effectively 19 How Organizations Get the Most from Their Data Data Mining – A method for better understanding data – Information on customers, products, markets, etc. – Drill down: from summary to more detailed data – Sort and extract information – Trends, correlations, forecasting, statistics 20 How Organizations Get the Most from Their Data Data Mining – Online Transaction Processing (OLTP) • Immediate automated responses to user requests • Multiple concurrent transactions • A big part of interactive Internet e-commerce 21 How Organizations Get the Most from Their Data Data Mining – Online Analytical Processing (OLAP) • Graphical software tools that provide complex analysis of data stored in a database • Drills down to deeper levels of consolidation • Time series and trend analysis • “What if” and “why” questions 22 How Organizations Get the Most from Their Data Data Mining – Merging Transaction and Analytical Processing • Real-time OLAP diminishes performance because the database must be “locked” during execution time • Solution: replicate transactions on a 2nd database server 23 How Organizations Get the Most from Their Data Data Mining – Merging Transaction and Analytical Processing • Operational Systems – Interact with customers and run a business in real time – Examples: Order processing, reservation systems • Informational Systems – Support decision making based on stable point-in-time or historical data 24 How Organizations Get the Most from Their Data Data Warehousing • Integrating multiple large databases into a single repository • Queries, analysis, and processing • Purpose: put key business information into the hands of decision makers • Cost: millions 25 How Organizations Get the Most from Their Data Data Marts • Instead of one large data warehouse, many organizations create multiple data marts • Each contains a subset of the data • Example: finance, inventory, personnel • Each data mart is customized for particular DSS applications • Cost: typically less than $1 million 26