Notes, abstracts, papers, exams and problems of Technology

SQL Cheat Sheet

Insert Data

INSERT INTO tabla(col1,col2) VALUES(val2,val2)
INSERT INTO tabla SET col1='va1',col2='val2'
INSERT INTO ON DUPLICATE KEY UPDATE ...
REPLACE INTO tabla VALUES ...

Update Data

UPDATE tabla SET col1='val1' WHERE ...
UPDATE tabla SET col1=(SELECT ...)

Delete Data

DELETE FROM tabla WHERE cond

Transactions

TRANSACTIONS:
START TRANSACTION;
INSERT INTO ...;
SAVEPOINT prueba;
INSERT INTO ...;
ROLLBACK TO SAVEPOINT prueba;
SET autocommit=0;
COMMIT;

Locking

LOCK TABLES tabla1 WRITE, tabla2 WRITE;
UNLOCK TABLES;

Stored Procedures

CREATE PROCEDURE nombre()
BEGIN
DECLARE a INT;
SELECT x INTO a ...;
END;
CALL procedure();

Functions

CREATE FUNCTION nombre(m VARCHAR(255))
RETURNS INT
BEGIN
DECLARE existe INT DEFAULT 1;
DECLARE tot, k INT;
DECLARE cur_1 CURSOR... Continue reading "SQL Cheat Sheet: Commands, Syntax, and Examples" »

Night Driving and Visibility

When driving at night, which lights should you be using?

You should be able to stop within the distance you can see ahead.

When driving in fog, what lights are best?

• Low beams, or
• Fog lights

Positioning and Signaling

Where should you position your car to make a left turn from a two-way street?

Use the lane nearest the center of the road.

When should you use your horn?

• When coming out of a dark alley.

Intersection Rules

What should be done if two cars enter an uncontrolled intersection simultaneously?

The driver to the left must yield to the driver on the right.

What is good practice when nearing an intersection?

• Slow down and be prepared to stop.

Road Markings

Where would yellow center lines usually be found?

On a two-way road (no... Continue reading "Essential Road Safety and Driving Practices" »

18) Mail-Enabling an Existing Contact:

1. Recipient Configuration
2. Mail Contact
3. Existing Contact
4. Locate the contact using the browser
5. OWA

20) Moving a Mailbox with Exchange Management Console:

1. Recipient Configuration
2. Mailbox
3. Select the desired mailbox
4. Move Mailbox
5. Browse and select the target database
6. Skip mailbox check
7. Select "Immediately" for the move timing.

21) Creating an ActiveSync Policy:

1. Organization Configuration
2. Client Access
3. New Exchange ActiveSync Mailbox Policy
4. Enter a name for the policy
5. Enable the "Allow attachments" checkbox (and other desired settings).

22) Assigning an ActiveSync Policy:

1. Recipient Configuration
2. Mailbox
3. Select the desired mailbox and open its properties
4. Mailbox Features
5. Exchange ActiveSync
6. Properties
7. Select the new policy.

23) Creating a

My Favorite Website

The website that I usually visit is NewPCT1. The page is full of text links. The appearance of this page is good, tidy, nice, and easy to use. The site map is well-organized because it divides the content into sections, and it is only necessary to choose the one that you wish to view. The search option arranges content by series, movies, programs, games, and music. Inside each of these sections, you have many subcategories to choose from. It is very comfortable to navigate this website. It has many links, but all are positioned in such a way that it is easy to use.

Unit 11: Networking Fundamentals

• File Server: A file server provides a central storage area for data files.
• Bridge: A bridge is a hardware and software combination

List of Essential ICT Services

1. List the services that must be provided in the new ICT and indicates which are mandatory and which are optional. Solution:

• Service radio and television (RTV): capture, adapt and distribute radio and television signals that reach the building, so they can be interpreted by the user receivers.
• Telephone service available to the public (STDP): providing access to telephone and data transmission through the basic telephone network (TB) or integrated services digital network (ISDN).
• Service broadband telecommunications: to provide access to telecommunications services broadband (television, data, etc.), cable (TBA) or a wireless (SAI), promoting the development of the Digital Home.

2. Description of the Common Area of

Q1. Synchronous

1. Asynchronous
2. Isochronous
3. None of the above

Q2. Full Duplex

1. Half Duplex
2. Simplex
3. All of the above

Q3. Modulation

1. De-modulation
2. Multiplexing
3. De-multiplexing

Q4. TDM

1. WDM
2. CDM
3. All of the above

Q5. FDM

1. TDM
2. WDM
3. CDM

Q6. Electrical

1. Light
2. Electromagnetic
3. All of the above

Q7. Less Susceptible

1. More Susceptible
2. Not Susceptible
3. None of the above

Q8. Fiber Optic

1. Twisted Pair Cable
2. Coaxial Cable
3. Both B & C

Q9. Reflected

1. Refracted
2. Travelling along the boundary
3. None of the above

Q10. Digital

1. Analogue
2. Both A & B
3. None of the above

Q11. Phase and in Amplitude

1. Phase and Frequency
2. Amplitude and Frequency
3. All of the above

Q12. Increased Unused Slots

1. Decrease the Unused Slots (Maybe)
2. Eliminating Unused Slots
3. Do Not Deal with Unused Slots

Q13. Mathematical Formula

1. Analogue Signal
2. Digital Signal
3. Any

Transformers

Alternating current can be increased or decreased by a transformer. This allows us to transfer electrical energy at very high voltages and over hundreds of kilometers, without losing any of the energy as heat. Transformers consist of two windings made of copper wire. If we apply an alternating current to one of them, it will produce a certain voltage in the other.

Electromagnetic Effects

He noticed that electricity could be generated by using a magnet and an electrical conductor. This principle allows us to build dynamos and alternators.

Effects of Electric Current: Heat

The movement of electrons through an electrical cable is both slow and disorderly. The electrons often collide, increasing the temperature of the cable itself.

Light

For... Continue reading "Understanding Transformers, Electromagnetic Effects, and Electrical Current" »

Industrial Transformations

Understanding Computer Networks

A computer network is a set of computers connected to each other, enabling them to share resources and exchange information. They can share printers, files, folders, and Internet connections.

Ethernet Classification

The two common types of Ethernet networks are 100Base-T and 1000Base-T.

The number indicates the transmission speed in Megabits per second: 100Mbps and 1000Mbps, respectively.

The letter 'T' indicates the type of cable used to transmit data. The cable consists of twisted pairs of copper wire with RJ45 connectors at each end. These cables are used to connect the network.

Types of Cables

• Twisted Pair UTP: 8 copper wires twisted together in 4 pairs with an RJ45 connector at the end.
• STP: A safer cable for transmitting