• Cơ sở dữ liệu - Chapter 10: Application development with viewsCơ sở dữ liệu - Chapter 10: Application development with views

    Must rename columns: - derived columns - multiple columns with the same unqualified names (CourseNo from Offering and Course) Example 2: - Row summaries - Derived column: NumStudents - Must provide a name for all columns when one column is renamed - Positional notation for column names Access: - Use AS in the SELECT clause for de...

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  • Cơ sở dữ liệu - Chapter 9: Supplemental slides type ii nested query demonstrationCơ sở dữ liệu - Chapter 9: Supplemental slides type ii nested query demonstration

    Query execution: - For each Faculty row, execute nested query on the Student table - Faculty row does not qualify in the result unless it does not match any Student rows.

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  • Cơ sở dữ liệu - Chapter 9: Advanced query formulation with sqlCơ sở dữ liệu - Chapter 9: Advanced query formulation with sql

    Type I nested query with NOT IN condition One-sided outer join with IS NULL condition Difference operation using MINUS (EXCEPT) operator

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  • Cơ sở dữ liệu - Chapter 8: Physical database designCơ sở dữ liệu - Chapter 8: Physical database design

    Minimize response time to access and change a database. Minimizing computing resources is a substitute measure for response time. Database resources Physical record transfers CPU operations Communication network usage (distributed processing)

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  • Cơ sở dữ liệu - Chapter 7: Normalization of relational tablesCơ sở dữ liệu - Chapter 7: Normalization of relational tables

    Insertion Insert more column data than desired Must know student number and offering number to insert a new course Update Change multiple rows to change one fact Must change two rows to change student class of student S1 Deletion Deleting a row causes other facts to disappear Deleting enrollment of student S2 in offering O3 causes loss of i...

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  • Cơ sở dữ liệu - Chapter 6: Developing data models for business databasesCơ sở dữ liệu - Chapter 6: Developing data models for business databases

    Identify entity types and attributes Determine primary keys Add relationships Determine connections Determine relationship cardinalities Simplify relationships

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  • Cơ sở dữ liệu - Chapter 5: Understanding entity relationship diagramsCơ sở dữ liệu - Chapter 5: Understanding entity relationship diagrams

    Identification dependency M-N relationships with attributes Self identifying relationships M-way relationships Equivalence between M-N and 1-M relationships

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  • Cơ sở dữ liệu - SQLCơ sở dữ liệu - SQL

    The GROUP BY clause is used to group rows to compute group-statistics.  The syntax of GROUP BY command is: SELECT attribute name, aggregate function FROM table name GROUP BY attribute name;

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  • Cơ sở dữ liệu - Normalization for relational databasesCơ sở dữ liệu - Normalization for relational databases

    Uses the concepts of FDs, primary key  Definitions: ◦ Prime attribute - attribute that is member of the primary key K ◦ Full functional dependency - a FD Y  Z where removal of any attribute from Y means the FD does not hold any more

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  • Cơ sở dữ liệu - Functional dependenciesCơ sở dữ liệu - Functional dependencies

    For a set X of attributes, we call the closure of X (with respect to a set of functional dependencies F), noted X+, the maximum set of attributes such that XX+ (as a consequence of F) Consider the relation scheme R(A,B,C,D) with functional dependencies {A}{C} and {B}{D}.  {A}+ = {A,C}  {B}+ = {B,D}  {C}+={C}  {D}+={D}  {A,B}+ = {A,...

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