Csc 1302, Honors Principles of Computer Science II (Fall 2021)

Week 1 (27 August 2021)

Database, Relation, Tuple

Sample Database Instance

Database Class: Encapsulates the entire database, which is nothing but a collection of relations (or tables); Variables include:

  Map<String,Relation> relations;

The key for the map is the name of the relation.

Java Map Documentation
Example - mkyong

Relation Class: Encapsulates a relation or table; includes both schema and instance. Variables include:

  // Name of the relation.
  private String name;

  // Attribute names for the relation
  private ArrayList<String> attributes;

  // Domain classes or types of attributes; possible values: INTEGER, DECIMAL, VARCHAR
  private ArrayList<String> domains;

  // Actual data storage (list of tuples) for the relation.
  private ArrayList<Tuple> table;

Tuple Class: Encapsulates a tuple or row of a relation; includes both schema and instance. Variables include:

  private ArrayList<String> attributes;
  private ArrayList<String> domains;
  private ArrayList<Comparable> tuple;

Java Comparable Documentation
Example - mkyong

TO DO

Download the Skeleton files and implement all the methods in these Java classes. Compile and run the driver program. You should see the following output:

[raj@tinman w1]$ java Driver
Database Schema
-------- ------

STUDENT(SID:INTEGER,SNAME:VARCHAR,MAJOR:VARCHAR,GPA:DECIMAL)
COURSE(CNUM:VARCHAR,CTITLE:VARCHAR,DESCRIPTION:VARCHAR,CREDITS:INTEGER)

STUDENT(SID:INTEGER,SNAME:VARCHAR,MAJOR:VARCHAR,GPA:DECIMAL)
Number of tuples: 2

1111:Robert Adams:Computer Science:4.0:
1112:Charles Bailey:Mathematics:3.0:

COURSE(CNUM:VARCHAR,CTITLE:VARCHAR,DESCRIPTION:VARCHAR,CREDITS:INTEGER)
Number of tuples: 2

CSc 1301:Intro to CS I:Java Programming and breadth topics:4:
CSc 1302:Intro to CS II:In depth Java Programming and some breadth topics:4: