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Midterm Exam Preparation Guide for Database Concepts and Normalization

This guide covers essential topics for the upcoming midterm on February 18, focusing on database concepts, normalization, and relational algebra. Key areas of study include unique rows, super keys, candidate keys, and how to avoid anomalies (deletion/insertion/update). You'll learn how to create ER diagrams, define cardinality and ordinality in relationships, and convert ER diagrams into tables. The midterm will consist of multiple-choice questions, ER diagrams, and relational algebra problems. Strategies for success include careful reading of questions, providing clear logic, and showing your work.

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Midterm Exam Preparation Guide for Database Concepts and Normalization

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  1. 2141-W2013Mid-term Prep

  2. Next week • Monday, Feb 18 • Midterm • Covers everything before normalization • Wednesday, Feb 20 • Ass 3 (normalization) due • Wrap up normalization • Friday, Feb 22 • Quiz 3 (normalization) • Set the stage for after spring break

  3. Core database concepts • Database records • Attributes and their domains • Rows must be unique • Keys: super, candidate, primary foreign • What are the anomalies trying to avoid: • Deletion/insertion/update

  4. Conceptual Database Design • How to take a description of a real-world rules and create an ER diagram • Specify cardinality/ordinality of a relationship • The differences between entities, attributes, and relationships (and when you might want to promote an attribute to an entity or a relationship to an associative entity) • How to indicate the primary key

  5. Logical Database design • How to convert an ER diagram to the appropriate set of tables • What are the rules for creating tables • For entities • For relationships of different cardinalities (1-1, 1-many, many-to-many) • For relationships of different modalities (unary, binary, ternary, etc.)

  6. Relational Algebra • Core operations • Select • Project • Rename • Union • Intersection • Set difference • Division • Cartesian product • Natural join • Conditional join (theta) • The format of the operation • Union compatibility • The schema of the relationship returned • The data in the relationship returned • How to parse a query • How to form a query • High level notion of efficiency

  7. Midterm format • ~ 5 short and snappy • Multiple choice • Compare/contrast/T or F and explain • ER diagram • ER diagram to tables • Relational algebra • As in quiz: • Do you know the basic mechanics • Can you parse what a query does • Can you create a query to achieve a goal Approximate weights • 20% basic concepts • 20% ER diagram • 20% ER diagram to tables • 40% Relational algebra Chinese menu?

  8. Strategies • Go for partial points • Show your work • Use comments • Explain what you are trying to achieve • Provide your interpretation • State any assumptions • Be neat – highlight (put a box around it) your final result if you have a lot of attempts • Use parentheses to help show your logic • Use partial steps and assign them to relations if it helps you think about it (R1 = ___), but make sure that it is clear what you are doing and how the pieces then fit together • Be succinct

  9. Relational Algebra • Do you know all the relations needed • Do you know the output needed (final projection/selection) • Do you know how to combine the parts

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