Database Concepts

Name: Troy Dowling scholar No: s3338219 Assignment 2 Q1. shortly explain each of the succeeding(a) database terms. Use no more(prenominal) than 2 -3 lines for each term. 1. DBMS: A (DBMS) Database Management arranging is a collection of softw atomic number 18 programs that drop out the introduction and concern of databases. A DBMS allows the company to mete out large amounts of data good and effectively. A DBMS is apply by a database administrator (DBAs). 2. Update Anomaly: A update anomaly is when one and only(a) tuple is updated save the aforementioned(prenominal) information in a nonher(prenominal) tuple is non counterchanged. A notification can be knowing so this can not happen. 3. also jazzn as (referring to postpones in SQL queries): An Alias (AS) can change the title of the mainstay in the table produced make use of SQL. e.g. To use TITLE for a principal of the column instead of MOVIE. 4. shaky Entity: A weak entity allows the creation of kindred named relations in different tuples. This allows multiple entries to overhear the same name just now different relations.

Q2 Q3A A = ITEM_NO, B = ITEM_DESCRIPTION C = CUST_NO D = CUST_CONTACT E = LOANDURATION F =SUPPLIERNAME G = DISCOUNT A: if (ac > e) and (e > g) hence victimization transitiveness replace (ac > e with ac > e, g) and except (e > g) if (ac > e, g) and (c > d) wherefore using augmentation and transitivity replace (ac > e, g with ac > e, g, d) remove (c > d) then make RHS singletons the remaining FD are: ac > e ac > d ac > g a>b a>f using FD on LHS to construe key for relation: FD = {ac > e ac > d ac > g a>b a>f} a+ = a, b, f ac+ = a, c, b, f, d, e, g = SUPERKEY {ace} = {ITEM_NO, CUST_NO} {ITEM_NO, CUST_NO} is the superkey because without these attributes you can not know any of the opposite attributes. B: R ( a b c d e f g) the FD (ac > d) is in BCNF, but the FD (a > b) is not as the LHS does not contain the superkey. c: BCNF impingement a > b {a+} = a, b, f R1 ( a* b f ) FDs = a > b, a > f = BCNF R2 ( a c d e g ) FDs = ac > e, ac > d, ac > g = BCNF comparison 1 (ITEM_NO, ITEM_DESCRIPTION, SUPPLIERNAME)...If you want to bugger off a full essay, parliamentary law it on our website: Ordercustompaper.com

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