Answer:
Explanation:
Duplicate tuples are not allowed in a relation because the specifications of the constraints of the regional integrity are violated, especially the main constraint that states that there can be no identical values for the attributes of two tuples at any database relation state.
Also, duplicate tuples are not allowed in a relation due to the fact that they lead to redundancy of the data base which in turn, slowing down the speed of the database when data processing such as inserting, querying, updating, deleting, etc are being performed.
Answer:
five types of pointing devices
Explanation:
Ponting devices
Pointing means point something and the pointing devices are the input /peripheral devices those are used to point the pointer on the screen. We do move cursor on the screen to open the files or any icon.
There are many types of pointing devices but these are quite common which are given below
- Computer mouse
- Finger on touch screen.
- Joystick.
- Leap Motion.
- Light pen (pen)
1.Mouse
Mouse is most common type of input device that is used for pointing the data on the screen. We press it with our hands and keep pointing the things.
There are three types of mouse
- optical mouse
- wireless mouse
- trackball mouse.
2. Finger on touch screen
In this type of movement the fingers are input devices those we use to see the movement of pointer on the screen and this is most common in this century.
3.Joystick.
Joystick is another input device to point the cursor but it is mostly used in games. Children can use it smartly so it is inculcated in games usually.
4. Leap Motion
The Leap Motion (LM) controller is a latest 3D sensing device for hand posture interaction with a computer. It is having the capability sense the location of the fingers of the hands, as well as the palm position.
5.Light Pen
this is another pointing device which is mostly used to highlight and select the data on the screen.
Note: All of these above pointing devices are most common used now a days. These devices are having new conventions day by day for the ease of user. This era is basically the era of IT ,so the use of computer must be so easy and conventional for the user so, the innovations and improvement in such devices is made side by side.
While a computer is running the operating system remains in memory is true.
C, <span>Word processing can be used to create databases of information.</span>
Answer:
The correct answer is A) "red"
Explanation:
Using arrays and lists are very helpful when writing programs. They help simplify programs by storing <u>related data</u> under one name.
In the question above the general name is <u>myList</u>. <em>The related data are red, orange, yellow, green, blue, indigo, and violet.</em>
This means that myList contains values a,b,c,d,e,f, and g. However myList[1] only contains value "red".
Cheers!
