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Ronch [10]
4 years ago
12

Consider the foreign-key constraint from the ‘dept name’ attribute of ‘instructor’ to the ‘department’ relation. Give examples o

f inserts and deletes to these relations that can cause a violation of the foreign-key constraint.
Computers and Technology
1 answer:
garri49 [273]4 years ago
5 0

Answer:

Inserting a tuple:

(10111, Ostrom, Economics, 110,000)

into the instructor table, where the department table does not have the

department Economics, would violate the foreign key constraint.

• Deleting the tuple:

(Biology, Watson, 90000)

from the department table, where at least one student or instructor

tuple has dept name as Biology, would violate the foreign key constraint.

employee (person name, street, city)

works (person name, company name, salary)

company (company name, city)

Explanation:

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What is something you can do to stay connected to the relationships in your life while we spend this time at home?
LekaFEV [45]

Answer: Anything that allows you to either talk or videochat with friends or family.

6 0
3 years ago
Identify the correct XHTML syntax for inserting an image as a hyperlink from the options provided. A. book.gif B. C. D.
mariarad [96]

Answer:

The Correct syntax for inserting an image as hyperlink is given in explanation section

Explanation:

To make an image act as a hyperlink, place the image element within the HTML anchor "<a></a>"  element.

The syntax of inserting image hyperlink in XHTML is given below.

<a href = "link_that_can_be_accessible"><img src="source of image" alt="display name if image not shown in the browser" border="0"/></a>

for example lets insert image as hyperlink

<a href="ajax.html"><img src="logo.gif" alt="AJAX" border="0" /></a>

The default appearance is a blue border around the image. Specifying border="0" removes the border around the image.

if you want to insert image from another folder then the image hyperlink looks like this:

<a href="ajax.html"><img src="/images/html5/logo.gif" alt="AJAX" border="0" /></a>

If you want to insert image from another server then image hyper link looks like this:

<a href="ajax.html"><img src="https://www.myExample.com/images/html5/logo.gif" alt="AJAX" border="0" /></a>

4 0
4 years ago
Write the SQL statements that define the relational schema (tables)for this database. Assume that person_id, play_id, birth_year
Sunny_sXe [5.5K]

Answer:

  • SQL statement that defines table for Actor

CREATE TABLE Actor(

person_id integer primary key,

name varchar2(40) not null,

birth_year integer check ((birth_year) <= 2019)

);

  • SQL statement that defines table for Play

CREATE TABLE Play(

play_id integer primary key,

title varchar2(60) not null,

author varchar2(60) not null,

year_written integer check ((year_written) <= 2019)

);

  • SQL statement that defines table for Role

CREATE TABLE Role (

person_id integer,

character_name varchar2(60) not null,

play_id integer,

constraint fk_person foreign key (person_id) references actor(person_id),

constraint fk_play foreign key (play_id) references play(play_id),

primary key (person_id, character_name, play_id)

);

Explanation:

Other information that were not added to the question are as below:

The following database contains information about three tables i.e. actors, plays, and roles they performed.

Actor (person_id, name, birth_year)

Play (play_id, title, author, year_written)

Role (person_id, character_name, play_id)

Where: Actor is a table of actors, their names, and the year they were born. Each actor has a unique person_id, which is a key.

Play is a table of plays, giving the title, author, and year written for each play. Each play has a unique play_id, which is a key.

Role records which actors have performed which roles (characters) in which plays.

Attributes person_id and play_id are foreign keys to Actor and Play respectively.

All three attributes make up the key since it is possible for a single actor to play more than one character in the same play

Further Explanation:

In SQL, in order to define relational schema (Tables) for a database, we use CREATE TABLE statement to create a new table in a database.  The column parameters specify the names of the columns of the table.  The datatype parameter specifies the type of data the column can hold (varchar, integer, date)

4 0
3 years ago
Who wont me???????????????
Svet_ta [14]

Answer:

whatatattatata

Explanation:

what are u talking about

8 0
3 years ago
Read 2 more answers
NAME SEARCH In the Chap07 folder of the Student Sample Programs, you will find the following files: GirlNames.txt—This file cont
Tems11 [23]

Answer:

Explanation:

I do not have the files listed in the question so I have made two test files with the same names. This code is written in Python, we are assuming that the names on each file are separated by newlines.

f1 = open("GirlNames.txt", 'r')

f1_names = f1.read()

f1_names_list = f1_names.split('\n')

f2 = open("BoyNames.txt", 'r')

f2_names = f2.read()

f2_names_list = f2_names.split('\n')

print(f1_names_list)

print(f2_names_list)

boy_or_girl = input("Would you like to enter a boy or girl name or both: ").lower()

if boy_or_girl == 'boy':

   name = input("Enter name: ")

   if name in f2_names_list:

       print("Yes " + name + " is in the list of most popular boy names.")

   else:

       print("No, it is not in the list")

elif boy_or_girl == 'girl':

   name = input("Enter name: ")

   if name in f1_names_list:

       print("Yes " + name + " is in the list of most popular girl names.")

   else:

       print("No, it is not in the list")

elif boy_or_girl == 'both':

   girlname = input("Enter Girl name: ")

   if girlname in f1_names_list:

       print("Yes " + girlname + " is in the list of most popular girl names.")

   else:

       print("No, it is not in the list")

   boyname = input("Enter name: ")

   if boyname in f2_names_list:

       print("Yes " + boyname + " is in the list of most popular girl names.")

   else:

       print("No, it is not in the list")

else:

   print("Wrong input.")

4 0
3 years ago
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