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Concept explainers
Primary Key:
A Primary Key in a
Example:
Students in Universities are assigned a unique registration number. Therefore, in a STUDENT database table, the attribute “reg_no” acts as primary key.
Foreign Key:
Foreign Key is a column in a relational database table which provides a relation between two tables. It provides a cross reference between tables by pointing to primary key of another table.
Example:
In STUDENT database table, the attribute “reg_no” acts as primary key and in COURSE database table in which the student selects his or her course, the same “reg_no” acts as foreign key for the STUDENT table.
Given database tables:
Table Name: EMPLOYEE
EMP_CODE | EMP_TITLE | EMP_LNAME | EMP_FNAME | EMP_INITIAL | EMP_DOB | STORE_CODE |
1 | Mr. | Williamson | John | W | 21-May-84 | 3 |
2 | Ms. | Ratula | Nancy | 09-Feb-89 | 2 | |
3 | Ms. | Greenboro | Lottie | R | 02-Oct-81 | 4 |
4 | Mrs. | Rumpersfro | Jennie | S | 01-Jun-71 | 5 |
5 | Mr. | Smith | Robert | L | 23-Nov-59 | 3 |
6 | Mr. | Renselear | Cary | A | 25-Dec-85 | 1 |
7 | Mr. | Ogallo | Roberto | S | 31-Jul-82 | 3 |
8 | Ms. | Johnson | Elizabeth | I | 10-Sep-88 | 1 |
9 | Mr. | Eindsmar | Jack | W | 19-Apr-55 | 2 |
10 | Mrs. | Jones | Rose | R | 06-Mar-66 | 4 |
11 | Mr. | Broderick | Tom | 21-Oct-72 | 3 | |
12 | Mr. | Washington | Alan | Y | 08-Sept-74 | 2 |
13 | Mr. | Smith | Peter | N | 25-Aug-64 | 3 |
14 | Ms. | Smith | Sherry | H | 25-May-66 | 4 |
15 | Mr. | Olenko | Howard | U | 24-May-64 | 5 |
16 | Mr. | Archialo | Barry | V | 03-Sep-60 | 5 |
17 | Ms. | Grimaldo | Jeanine | K | 12-Nov-70 | 4 |
18 | Mr. | Rosenburg | Andrew | D | 24-Jan-71 | 4 |
19 | Mr. | Rosten | Peter | F | 03-Oct-68 | 4 |
20 | Mr. | Mckee | Robert | S | 06-Mar-70 | 1 |
21 | Ms. | Baumann | Jennifer | A | 11-Dec-74 | 3 |
Table Name: STORE
STORE_CODE | STORE_NAME | STORE_YTD_SALES | REGION_CODE | EMP_CODE |
1 | Access Junction | 1003455.76 | 2 | 8 |
2 | Database Corner | 1421987.39 | 2 | 12 |
3 | Tuple Charge | 986783.22 | 1 | 7 |
4 | Attribute Alley | 944568.56 | 2 | 3 |
5 | Primary Key Point | 2930098.45 | 1 | 15 |
Table Name: REGION
REGION_CODE | REGION_DESCRIPT |
1 | EAST |
2 | WEST |
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Chapter 3 Solutions
EBK DATABASE SYSTEMS: DESIGN, IMPLEMENT
- 6. See the code below and solve the following. import java.io.*; public class DataStream { } public static void main(String[] args) } DataOutputStream output = new DataOutputStream(new FileOutputStream("temp.dat")); output.writeUTF("Book1"); output.writeInt(85); output.writeUTF("Book2"); output.writeInt(125); output.writeUTF("Book3"); output.writeInt(70); output.close(); // ToDo: Read all data from temp.dat and print the data to the standard output (monitor) 6-1. This program has a compile error, and the message is “Unhandled exception type FileNotFoundException". How do you fix this error? (1 point) 6-2. Is FileNotFoundException a checked exception or an unchecked exception? (1 point) 6-3. What is the difference between checked exception and unchecked exception? (1 point) 6-4. Please complete the above program by reading all data from temp.dat and print the data to the standard output (monitor) by using System.out.print, System.out.println or System.out.printf method. (2 points)arrow_forwardWrite a program that reads a list of integers from input and determines if the list is a palindrome (values are identical from first to last and last to first). The input begins with an integer indicating the length of the list that follows. Assume the list will contain a maximum of 20 integers. Output "yes" if the list is a palindrome and "no" otherwise. The output ends with a newline. Hints: - use a for loop to populate the array based on the specified size (the first number entered) - use a for loop to check first value with last value, second value with second from end, etc. - if the values do not match, set a Boolean variable to flag which statement to output (yes or no) Ex: If the input is (remember to include spaces between the numbers): 6 1 5 9 9 5 1 the output is: yes Ex: If the input is: 5 1 2 3 4 5 the output is: C++ codingarrow_forwardDesign and draw a high-level "as-is" process diagram that illustrates a current process related to a product or service offered through the SSDCI.gov database.arrow_forward
- Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781305627482Author:Carlos Coronel, Steven MorrisPublisher:Cengage LearningA Guide to SQLComputer ScienceISBN:9781111527273Author:Philip J. PrattPublisher:Course Technology Ptr
- Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781285196145Author:Steven, Steven Morris, Carlos Coronel, Carlos, Coronel, Carlos; Morris, Carlos Coronel and Steven Morris, Carlos Coronel; Steven Morris, Steven Morris; Carlos CoronelPublisher:Cengage LearningNp Ms Office 365/Excel 2016 I NtermedComputer ScienceISBN:9781337508841Author:CareyPublisher:Cengage
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