Network concepts, technologies, and database fundamentals notes:

4G LTE:

(Long-Term Evolution) network.

Different dial up connections:

*Dial-up: Up to 56 Kbps. Plain old telephone service. A regular analog phone line *DSL: Up to 30 Mbps. Digital subscriber line. Shares existing phone wires with voice service *Cable: Up to 50 Mbps. Inexpensive broadband Internet access method with wide availability. *Fiber-optic: Up to 1 Gbps. Incredibly fast and just as expensive. *Cellular: Up to 20 Mbps (realistically)Great range; supported by cellular providers. Best for a very limited number of devices. *Satellite: Up to 25 Mbps. For rural or remote areas without cabled broadband methods *Radio frequency: Up to 20 Mbps. For rural areas where cable and DSL are not available. Limited number of providers and availability

Database roll examples:

*db_owner: Full access (read, write, delete, back up) *db_datareader: Read datadb_datawriterAdd, delete, or modify *datadb_bckupoperator: Back up the *databasedb_denydatareader: Can't view *datadb_denydatawriter: Can't add, delete, or modify data

Potential disadvantages of using DSL:

-DSL may not be available in your area. There are distance limitations as to how far away from the phone company's central office you can be to get DSL. Usually this isn't a problem in metro areas, but it could be a problem in rural areas. -DSL requires more hardware than dial-up: a network card, a network cable, a DSL modem, a phone cord, and line filters for each phone in the home. And you usually pay a monthly rental fee for the DSL modem. -The cost is higher. Lower-speed packages often start off at around $30 to $40 per month, but the ones advertised with great data rates can easily run you $100 a month or more. -If you are in a house or building with older wiring, the older phone lines may not be able to support the full speed for which you were paying.

Advantages to using cable:

-It's much faster than dial-up, and it can be faster than DSL (particularly for uploads). -You're not required to have or use a telephone landline. -It's generally very reliable (depending on your ISP).

Advantages of using DSL:

-It's much faster than dial-up. -Your bandwidth is not shared with other users. -It's generally very reliable (depending on your ISP).

Two major cellular standards:

-The Global System for Mobile Communications (GSM) is the most popular, boasting more than 1.5 billion users in 210 countries. -The other cellular standard is code division multiple access (CDMA), which was developed by Qualcomm and is available only in the United States. *Both are considered 3G (or third-generation) mobile technologies

The following must be true for primary keys:

-The data in the combination of columns must be unique. (For example, if a database uses first_name and last_name fields together as the primary key, one person can have the name Joe Smith, and one person can be Jane Smith. But a second Jane Smith would not be allowed.) *No values in the column can be blank or null.

Benefits of a dial up connection:

-The only hardware it requires is a modem and a phone cord. -It's relatively easy to set up and configure. -It's the cheapest online solution (usually $10 to $20 per month). -You can use it wherever there is phone service, which is just about everywhere.

Setting up a secured wireless router:

1. Change the routers SSID 2. Change the administrator username and password 3. Enable WPA2 personal with AES encryption 4. Choose a high-quality passphrase 5. From the clients, select WPA2 and enter the security passphrase to connect

relational database-

A database that is predictable and organized, with tables containing columns and rows of text or numerical data.

LAN is-

A local area network (LAN) is a small network, usually confined to one office or building.

There are two types of firewalls: network-based and host-based

A network-based firewall is designed to protect a whole network of computers and almost always is a hardware solution with the software on it. Host-based firewalls protect only one computer and are almost always software solutions.

File Transfer Protocol (FTP)-

A protocol in the TCP/IP protocol suite that is optimized for file transfers. It uses ports 20 and 21.

Routers-

A router is a highly intelligent network connectivity device that can connect multiple network types to each other.

Network Address Translation (NAT)-

A service that translates private, nonroutable IP addresses into public addresses that can be used on the Internet.

Switch-

A switch is the network connectivity device at the center of most networks

WAN is-

A wide area network (WAN), as its name implies, is larger. Think of it as two or more LANs connected to each other. A WAN configuration is usually spread across multiple geographical areas and certainly requires the use of a router.

A unique address is called?

An IP address

Access point-

An access point is any point that allows a user on to a network. The term is commonly used in reference to a wireless access point, which lets users connect to your network

Quaries-

Are the real power of databases

Fields-

Columns in a table

Where can you check if DSL is available in your area?

DSLReports

DOCSIS=

Data Over Cable Service Internet Specification

Schema-

Defines as the rules and structure of the database.

Digital subscriber line DSL=

Digital Subscriber Line (DSL) A technology that uses regular telephone lines to carry high speed Internet.

DSL=

Digital subscriber line

Document database-

Each record and its associated data is considered a document

All databases are managed by a database management system (DBMS), and relational databases use a relational database management system (RDBMS).

Ensures data integrity by enforcing the following principles: -No duplicate rows are allowed. -Column values must not be arrays or repeating groups of data. -Where data is not present, null values are used.

TCP/IP protocol to its DOD model layer:

Ethernet= Network access ICMP= Internet UDP= Host to host SMTP= Process/ application

FTTH=

Fiber to the home service

File Server-

File server is a server computer that is specialized to store user files. It can be a dedicated or nondedicated server. The primary hardware requirement for a file server is lots of hard drive space. Oftentimes, file servers will have multiple optical drives as well.

Firewalls can be software-based, hardware-based, or a combination of both.

Firewalls can be stand-alone "black boxes," software installed on a server or router or some combination of hardware and software. Many routers have firewall capabilities.

Firewalls filter network traffic-

Firewalls filter inbound and outbound network traffic based on rules defined by the administrator. That list of rules is called an access control list (ACL). By default, most firewalls are configured as default deny, which means that all traffic is blocked unless specifically authorized by the administrator.

Constraints can also be placed on fields..

For example, if a field is set to accept integers only, users will not be allowed to enter text data.

Semi-structured data-

Generally thought of as unstructured data that has been tagged with metadata. Metadata is literally data about data.

Satellite Internet:

Instead of a cabled connection, it uses a satellite dish to receive data from an orbiting satellite and relay station that is connected to the Internet. *Another drawback to satellite technology is the delay (also called connection delay), or latency

Most common external connection type?

Internet

ISP=

Internet Service Provider

Relational databases-

Is an example of structured data. A relational database is predictable and organized, with tables containing columns and rows of text or numerical data. Data in a relational database must conform to specific rules as specified in the schema, and generally speaking, data is easy to search for and access.

Satellite Internet is often referred to as:

Line of sight wireless because it does require a clear line of sight between the receiver and the transmitter.

LAN=

Local Area Network

Mobile hotspot-

Many cellular providers offer network cards (or they incorrectly call them modems) that allow your laptop computer or other noncellular device to connect to the cellular network (and the Internet) from anywhere you can get a cellular signal.

Network-based firewalls separate public vs. private networks and can also create a DMZ.

Most network-based firewalls have at least two network connections: one to the Internet, or the public side, and one to the internal network, or private side. Some firewalls have a third network port for a second semi-internal network. This port is used to connect servers that can be considered both public and private, such as web and email servers. This intermediary network is known as a demilitarized zone (DMZ). A DMZ can also be configured as a space between two firewalls.

Permissions-

Permissions can be managed programmatically with the grant, deny, and revoke commands in the DBMS. The grant command grants permissions to users or roles, and deny explicitly denies permissions. The revoke command removes previously granted or denied permissions. If there is a conflict, such as a user account has been granted a permission but a role the user belongs to has been denied a permission, the deny will override the grant.

POTS=

Plain old telephone service

RAS=

Remote service access

key/value database-

Represents data as a collection of key/value pairs and manages associative arrays of data. database dump

plain old telephone service (POTS)

Standard telephone service, as opposed to other connection technologies like Digital Subscriber Line (DSL).

SQL means?

Structured Query Language (SQL)

connection delay-

The amount of delay between sending a network data request and receiving a response.

Flat file-

The data has two dimensions, rows and columns. *Flat files are meant to be single-user instances, even if several users may be able to access them at the same time.

Schema-

The rules and structure of the database. There are two types of schemas in relational databases: the logical schema and the physical schema. The logical schema outlines the structure of the database, such as the tables and their fields (columns), and relationships between tables. Logical schemas can be created by almost any visual diagramming software package or even in a spreadsheet The physical schema is the actual tables, columns, and relationships created in the RDBMS

Online gamers are especially sensitive to latency.

They often refer to it as ping time. The higher the ping time (in milliseconds), the worse the response time in the game. It sometimes means the difference between winning and losing an online game.

WAN=

Wide Area Network

Radio Frequency Internet-

Wireless (noncellular) radio frequency (RF) broadband Internet access is the least popular broadband connection in use today. *Also known as fixed wireless

Two types of wired connections:

Your two choices are unshielded twisted pair (UTP), which is copper and transmits using electrical pulses, and fiber-optic, which is made of glass or plastic and transmits using light. You'll run one of the two (or maybe a combination of the two), with UTP being by far the most common choice.

Server permissions-

affect the entire server. These would typically be granted to an administrator account. Sometimes you will hear these referred to as global permissions because they apply to all databases on that server.

Database permissions-

apply to one database and all objects within the database. These can be global as well, if they are applied to all databases on a server.

Reports-

are generated to answer specific questions

Point-to-multipoint-

because one satellite can provide a signal to a number of receivers simultaneously. It's used in a variety of applications from telecommunications and handheld GPSs to television and radio broadcasts and a host of others

Forms-

how data is entered into and often viewed from your database

Non-structured data-

include pictures, videos, web pages, emails, documents, texts, and social media. Realize that this data has structure within itself.

Different forms of DSL:

including high bit-rate DSL (HDSL), very high bit-rate DSL (VDSL), rate-adaptive DSL (RADSL), symmetric DSL (SDSL), and asymmetric DSL (ADSL). The most popular in-home form of DSL is ADSL.

Key/value database:

key/value database, data is represented as a collection of key/value pairs. Key/value databases manage associative arrays of data, also known as a dictionary, which is a collection of objects or records.

Key/value databases are also known as:

key/value stores.

Macros and modules-

let you add functionality to your database

Network attached storage-

network-attached storage (NAS) device takes hard drive storage to the next level. Based on its name, you can probably guess that it's attached to the network, which it is, but that's just the beginning

Non-structured data is also referred to as:

often referred to as unstructured data.

Foreign Keys-

one or more columns in a table that refers to the primary key in another table. Foreign keys are not required, and they don't need to be officially designated in the RDBMS (although they can be defined by the administrator in the index). *Can contain duplicate values and null values, and there are no limits to the number of foreign keys in a table.

Primary key-

one or more fields whose data is used to identify a record uniquely.

Object permissions-

will affect specific database objects, such as tables, views, forms, indexes, and macros or modules.