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Lecture 5 MIS/Decision Support Content for Weeks 5 and 6 • Discussion of OLTP v MIS/Decision Support • Review characteristics of a Normalised Relational Data Model • Consider the suitability of relational model for online transaction processing (OLTP); table access example • Consider the unsuitability of relational model for informational processing; table access example • Consider why organisations will generally implement informational systems on a different platform to the transaction processing systems CO6002 Modern Databases Lecture 5 2 Decision-making As defined by Baker et al in their 2001 study “efficient decision-making involves a series of steps that require the input of information at different stages of the process, as well as a process for feedback”. CO6002 Modern Databases Lecture 5 3 Decision Making Process Decision making at different levels • Operational • Tactical • Strategic Information and knowledge form the backbone of the decision making process CO6002 Modern Databases Lecture 5 4 Types of Decision Making Operational • Related to daily activities with short-term effect • Structured decisions taken by lower management Tactical • Semi-structured decisions taken by middle management Strategic • Long-term effect • Unstructured decisions taken by top management • Decision making steps include • Problem identification • Finding alternative solutions and making a choice CO6002 Modern Databases Lecture 5 5 DIKDA Cycle User Decision Making Triggering To be used in Applies Intelligence to Analysis Knowledge Forming Data CO6002 Modern Databases To produce Lecture 5 Action Generating more Information 6 Decisions • • Made up of a composite of information, data, facts and beliefs. Data by itself does not constitute useful information unless it is analysed and processed. CO6002 Modern Databases Lecture 5 7 A Decision • Is only as good as the data that informed it • Is only as good as the system which exists to implement it • Is only good if you have the means to implement it • Is only good if other people understand it and are agree/ready to implement it CO6002 Modern Databases Lecture 5 8 Operational vs. Informational Processing CO6002 Modern Databases Lecture 5 9 OLTP and OLAP OLTP • On-line Transaction Processing • Concerned with day to day running of the business OLAP • On-line Analytical Processing • Analysis of large amounts of data for management decision-making purposes • Often historical and multi-site CO6002 Modern Databases Lecture 5 10 OLTP vs. OLAP (MIS Decision Support) CO6002 Modern Databases Lecture 5 11 On-line Transaction Processing (OLTP) • • • Relational databases are optimized for OLTP and are designed to meet the day-to-day operational needs of the business. OLTP systems tend to organize data around specific processes, such as order entry. Performance is tuned for those operational needs by using a normalized data model which stores data by using database normalization rules. Consequently, the database can retrieve a small number of records very quickly. Attempting to use a database that is designed for OLTP as a data warehouse will result in a very slow query performance making it difficult to perform analysis on the data. CO6002 Modern Databases Lecture 5 12 OLAP or Decision Support System (DSS) Processing In a data warehousing environment, the relational databases need to be optimized for data retrieval and tuned to support the analysis of business trends and projections. This type of informational processing is known as online analytical processing (OLAP) or decision support system (DSS) processing. OLAP is also the term that database designers use to describe a dimensional approach to informational processing. CO6002 Modern Databases Lecture 5 13 OLAP Characteristics • • A dimensional database needs to be designed to support queries that retrieve a large number of records and that summarize data in different ways. A dimensional database tends to be subject oriented and aims to answer questions such as, “What products are selling well?” “At what time of year do certain products sell best?” “In what regions are sales weakest?” In a dimensional data model, the data is represented as either facts or dimensions. A fact is typically numeric piece of data about a transaction, such as the number of items ordered. A dimension is the reference information about the numeric facts, such as the name of the customer. Any new data that you load into the dimensional database is usually updated in a batch, often from multiple sources. CO6002 Modern Databases Lecture 5 14