Normalisation – Part 3 Summary and Discussion Summary of Normal Forms 1NF, 3NF and BCNF are popular in practice. Other normal forms are rarely used. 1NF: only atomic values for attributes (part of the definition for the relational data model); 2NF: an intermediate result in the history of database design theory; 3NF: lossless and dependencies […]
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1 Introduction to Data Science Lecture 7 Data Integration, Information Retrieval CIS 5930/4930 – Fall 2021 Assignments CIS 5930/4930 – Fall 2021 • Homework 1 • Posted on Canvas 9/10 • Due 9/17 3pm on Canvas Data Integration 1. Enterprise Information Integration: making separate DB’s, all owned by one company, work together. 2. Scientific DB’s,
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Query Optimisation Query Optimisation In practice, query optimisers incorporate elements of the following three optimisation approaches: Semantic query optimisation Use application specific semantic knowledge to transform a query into the one with a lower cost (they return the same answer). Rule-based query optimisation Use heuristic rules to transform a relational algebra expression into an equivalent
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Introduction to Database Systems – Part 1 General Concepts What is a Database? Have you designed a database? Have you worked with a database? Definition of Databases A database is a collection of related data. Implicit properties: represents some aspects of the real world; a logically coherent collection of data; designed and built for a
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8/25/2021 1 Introduction to Data Science Lecture 2 Data Science, Structured Data CIS 5930/4930 – Fall 2021 What is Data Science • Relatively new Computer Science field • Systems, algorithms, and processes for managing and deriving insights from heterogeneous and/or large data sets CIS 5930/4930 – Fall 2021 Typical Workflow for a Data Scientist CIS
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COMP2400/6240 – Relational Databases Assignment on Database Theory Assignment on Database Theory (Solutions) Due date: 23:59, 8 October 2019 This assignment will be marked out of 15. It will count for 15% of the final grade. Marks are assigned for the process of finding a solution, not only for the result. Hence, include all essential
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9/7/2021 1 Introduction to Data Science Lecture 6 Dirty Data, Essentials of Data Cleaning and Integration CIS 5930/4930 – Fall 2021 Dirty Data CIS 5930 – Fall 2020 Dirty Data CIS 5930 – Fall 2020 Dirty Data CIS 5930 – Fall 2020 Dirty Data CIS 5930 – Fall 2020 Dirty Data CIS 5930 – Fall
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1/81 Week 3 Workshop 2/81 Housekeeping 1 Thank you again for providing us with your valuable feedback! 2 Refer to the post in Wattle News Forum for makeup information for the CECS teaching pause. 3 Assessment on SQL (Assignment 1) will be available on Wattle at 11:59pm on Aug 20 (Friday) and due at 11:59pm
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1/42 Week 10 Workshop – Database Transactions Designing Data-Intensive Applications, Martin Kleppmann, O’Reilly, 2015 2/42 Transactions A transaction is a sequence of database operations grouped together for execution as a logic unit in a DBMS. Steps Transaction BEGIN TRANSACTION 1 SELECT balance FROM ACCOUNT WHERE name = ’Steve’; 2 UPDATE ACCOUNT SET balance = balance-500
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Database Security – Part 1 Introduction Introduction Why database security? Databases often store data that are sensitive in nature. Databases need to preserve data integrity. . . . Example: Consider a payroll database, it must be ensured that: Salaries may not be disclosed to arbitrary users of the database; Salaries can only be modified by
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