Referential integrity constraints check INSERT and UPDATE actions that have an impact on parent-child relationships.
Why is referential integrity important? What is it?In database design, the term "referential integrity" is used to describe the connection between two tables. It is crucial because it guarantees that all of the data in a database is accurate and consistent. It aids in preventing the addition, deletion, or modification of incorrect records.
What guidelines must users follow when referential integrity is enforced?A foreign key must match a primary key or be null in order to maintain referential integrity. This constraint maintains the correspondence between the rows in the parent and child tables between which it is specified.
To know more about database visit:-
brainly.com/question/28391263
#SPJ4
Which buttons are displayed by default on the quick access toolbar?
The default buttons appearing on the Quick Access Toolbar are Copy, Paste, and Run buttons New, Open, Save, Quick Print, Undo, Redo, Cut, etc
The Quick access toolbarThe Quick Access Toolbar gives you quick access to frequently used commands and gives you the opportunity to add your own custom commands to the toolbar. The Quick Access Toolbar's default layout includes the New, Open, Save, Quick Print, Run, Cut, Copy, Paste, Undo, and Redo buttons.
When utilising the undo and redo commands, be in mind that these operations might not apply to options or data that have been updated across all panels. In addition, the undo or redo command will undo all of the stated changes in a single operation if you modify many settings in a single panel, for instance.Text, objects on the HTML and Document canvases, and fields on the Report canvas can all be edited using the Cut, Copy, and Paste commands.The Customize Quick Access Toolbar menu is accessible by selecting the Customize Quick Access Toolbar button (down arrow) on the Quick Access Toolbar. The toolbar's standard commands are listed in this menu. These commands can be cleared to remove them from the toolbar. Additional command addition choices, moving the Quick Access Toolbar below the ribbon, and hiding the ribbon are also available through the Customize dialogue box.
To know more about Quick access toolbar refer to:
https://brainly.com/question/13523749
#SPJ4
hard drives that can be used for hot-swapping cost significantly less than regular hard drives.T/F
Hot-swappable hard drives are considerably less expensive than standard hard drives.
Users of computers with hot swap storage hard drives can replace or remove a hard drive without disturbing or turning off the system. When a hard disk in a storage array dies, a backup drive can be used right away without shutting down the entire system, saving time and money. Technologies have made storage device maintenance and applications simpler with the introduction of hot-swappable hard drives. Hard drives designed for hot swapping often cost more than standard hard drives. The supplied statement is untrue as a result. A swap file is a hard disk area used by computers to expand their virtual memory (RAM). By using a swap file, a computer might use more memory than what is actually placed in it. Data from RAM is "swapped" onto a file or region on the hard drive to free up space.
Learn more about Hard drives here:
https://brainly.com/question/29749375
#SPJ4
A user is having problems with a PC after visiting a website and downloading a file. Which of the below would categorize problems accessing a folder after downloading this file
After choosing file, you would then pick save as to locate a location on the computer to save the document.
After choosing file, you would then pick save as to locate a location on the computer to save the document. What is an order? In computing, a command is a request made to a computer program to complete a certain task. It could be sent via a command-line interface, such as a shell, as input to a network service as part of a network protocol, as an event in a graphical user interface triggered by the user selecting an item from a menu, or as a command transmitted over a network to a computer. You must first save the current document if you want to create a new one, alter its name or format, or store it in a different location on your computer.
Learn more about Command here:
https://brainly.com/question/30230878
#SPJ4
question 3 this is not the result we were hoping for, look carefully at the id column, can you see why we got this answer? why did the count return this result?
The COUNT return this result Because some IDs are invalid.
COUNTR FunctionThe COUNT function counts the number of cells containing numbers, and counts the numbers in the argument list. Use the COUNT function to get the number of entries in a number field that are in a range or array of numbers. For example, you can enter the following formula to count the numbers in the range A1:A20: =COUNT(A1:A20). In this example, if there are five cells in the range containing numbers, the result is 5.
Your question is incomplete but most probably your full question was:
the total Price Paid for all Terraced properties sold in 2014. Make any necessary adjustments and then drag the formula down
Q3. This is not the result we were hoping for, look carefully at the ID column, can you see why we got this answer?
Why did the COUNT return this result?
• Because some IDs have spaces
• Because some IDs are blank
• Because some IDs contain text characters
• Because some IDs are invalid
Learn more about COUNT at https://brainly.com/question/28272296.
#SPJ4
theresa is implementing a new access control system and wants to ensure that developers do not have the ability to move code from development systems into the production environment. what information security principle is she most directly enforcing?
Theresa is most directly enforcing the principle of least privilege (POLP), which is a key principle in information security that limits access to resources and functionality to only those who need it to perform their job duties.
What is principle of least privilege (POLP)?
The principle of least privilege (PoLP) is an information security notion which is also identified as the principle of minimal privilege or the principle of least authority. It states that any user, device, workload, or process should only have the privileges necessary to perform its intended function.
The term privilege refers to system rights or data access in this context. It determines, for example, which users have access to a specific file or which devices can connect to a specific network. It is also used to specify what users on a system can and cannot do.
Some users, for example, may be limited to performing specific functions, whereas others may be able to perform more, such as restarting the application or applying updates.
To learn more about principle of least privilege (POLP), visit:
https://brainly.com/question/30060860
#SPJ4
88.9% complete question an employee is responsible for protecting the privacy and rights of data used and transmitted by an organization. the employee dictates the procedures and purpose of data usage. a role is created at an organization to protect the privacy and rights of any data that is used and transmitted. which role governs and dictates the procedures and purpose of data usage?
The role created at an organization to protect the privacy and rights of any data that is used and transmitted is of the data controller, who governs and dictates the procedures and purpose of data usage.
What is a data controller?A person, business, or other entity that chooses the objectives and tools for processing personal data is known as a data controller. A private firm or any other type of legal entity, such as an incorporated association, incorporated partnership, or public authority, may act as a data controller.
Any Personal Data that it has is handled according to the purposes and methods determined by the Data Controller. The Data Controller is in charge of making sure that the processing of Personal Data adheres to the Data Protection Regulations.
To learn more about personal data, visit
https://brainly.com/question/11856386
#SPJ4
You are trying to install Hyper-V on a new laptop, but you keep receiving an error during installation that the software is not able to be installed. Which of the following characteristics of the laptop's processor should you investigate as the MOST likely issue
Virtualization support is the characteristic of the laptop's processor that should be investigated when there is an error during installation that the software cannot be installed.
What is VT support?VT stands for Virtualization Technology. It refers to a group of processor extensions that let the host operating system operate guest environments (for virtual machines) and process privileged instructions so that the guest operating system can function as though it were running on a real computer.
Virtualization boosts IT agility, flexibility, and scalability while generating considerable cost savings by converting the conventional rigid, complex infrastructure of individual servers, storage, and network hardware into a flexible virtual resource pool. The requirement to rebuild the method for dealing with system reliability is a disadvantage of virtualization. Because multiple virtual machines are running on the same physical server, the failure of the host causes simultaneous failure of every VM.
To learn more about virtualization support, visit:
https://brainly.com/question/4552970
#SPJ4
what spreadsheet tool will save you time by enabling you to create a dropdown list with need to apply and applied as the possible options?
Professionals in a variety of fields utilize the spreadsheet program Excel for data analysis and visualization.
If your profession requires you to work with a lot of data, you can utilize Excel's capabilities to track information, do simple computations, and organize data. Excel provides a wide range of effective tools that can perform a variety of tasks more quickly, easily, and effectively. We describe Excel tools in this article, along with their importance and practical application. The Excel program's tools are crucial components that make it easier and quicker to organize numbers and data formulae. They are effective and beneficial for companies of all sizes. Each tool has approximately 500 functionalities, and each one addresses a distinct issue.
Learn more about visualization here-
https://brainly.com/question/12362123
#SPJ4
the form and keying style that a typist uses while operating the keyboard is called
Technique is the form and keying style that a typist uses while operating the keyboard.
What is keyboard?A computer keyboard is a sort of peripheral input device that is similar to a typewriter keyboard in that it employs a series of buttons or keys to operate as mechanical levers or electrical switches. A keyboard is a piece of hardware that allows a user to enter text into a computer or other electronic device. A keyboard is an input device that allows a user to interface with a computer in the most basic way. A keyboard is an input device made up of a series of buttons known as keys. We use the keyboard to enter data and offer input to the computer.
Here,
A typist's technique is the form and keying manner that he or she employs when operating a keyboard.
To know more about keyboard,
https://brainly.com/question/24921064
#SPJ4
swapping items between memory and storage is called ?
The process of shifting objects between memory and storage is known as paging.
What is computer storage?Computer data storage is a technique that uses computer components and recording media to store digital data. It is an essential function and component of computers. A computer's central processor unit manipulates data by conducting computations. Storage is a method that allows a computer to keep data indefinitely or temporarily. Storage devices, such as flash drives and hard disks, are essential components of most digital devices because they allow users to save various types of data, such as films, documents, images, and raw data.
Here,
Paging is the process of shifting things between memory and storage.
To know more about computer storage,
https://brainly.com/question/11049355
#SPJ4
Write the steps for viewing tab stops in a word document
Tab stops are used to align text in Word documents.
Create a word document with the instructions for viewing tab stops?Here are the steps to view tab stops in a Word document:Open the Word document you want to view the tab stops from.Click on the “Home” tab in the Ribbon menu.Click on the “Paragraph” group.Click on the “Paragraph” dialog box launcher.A dialog box will appear.Click on the “Tabs” button in the bottom left corner.A new dialog box will appear with a list of tab stops and their positions.The tab stops are marked on the ruler at the top of the dialog box.The tab stop positions can be adjusted by dragging the tab stops on the ruler.To delete a tab stop, click on the tab stop on the ruler and press the “Delete” key.When you are finished editing the tab stops, click “OK” to save your changes.The tab stops will now be visible in your document.To learn more about align text in Word documents refer to:
https://brainly.com/question/25813601
#SPJ1
Describe how technology is impacting global events such as political revolutions, health care, the environment, and the digital divide. in addition, address how business is using social media.
Develop and administer vaccinations; Increase vaccine manufacturing; Embedded sensors offer crucial data. The environmental data may inform scientists about emerging patterns.
What is the digital literacy and media divide?The phrase "digital divide" describes the difference in demographics and geographic areas with and without access to contemporary information and communications technology (ICT). The internet, personal computers, television, and telephone are examples of this technology.
Which effects does the digital divide have on healthcare?In the field of healthcare, the digital divide may result in differences in the use of patient-facing practice management tools, such as online appointment schedulers, or in access to telehealth services.
To know more about sensors visit :-
https://brainly.com/question/15396411
#SPJ4
phi in written or verbal form is considered secure.T/F
Answer:
The security role
Explanation:
The Security Rule calls this information "electronic protected health information" (e-PHI). The Security Rule does not apply to PHI transmitted orally or in writing.
which of the following prevented early windows operating systems from supporting enterprise functions? lack of processing speed. lack of security. lack of chips. users did not know how to operate the system.
Early Windows operating systems couldn't provide enterprise functions because of a lack of chips.
What operating system was used before to Windows?From Windows' initial release in 1985 all the way up to these exciting times with Windows 11, PCMag has covered Microsoft's operating system. Without MS-DOS (Disk Operating System), which came before Windows, the PC revolution would not have occurred. We utilized and wrote about MS-DOS.
How did Windows 7 get its name?The project was given the codename Windows 7 since Windows Vista's programmatic version number was 6.0, and because this was the upcoming version, it seemed only appropriate to label the following version 7.0.
To know more about operating systems visit:-
https://brainly.com/question/6689423
#SPJ4
1. You need to install a customized console on 10 computers. What is the best way to do that?
a. When installing the console on the first computer, write down each step to make it easier to do the same chore on the other nine.
b. Create the console on one computer and copy the .mmc file to the other nine.
c. Create the console on one computer and copy the .msc file to the other nine.
Creating a computer object in Active Directory requires that the name of the machine match the one entered during Windows installation.
Use the complete New-AD Computer to create one or more computer objects with the required specifications. The New-AD User complete can be used to generate intersperse accounts as well as other kinds of user accounts. To do this, in Active Directory Domain Services (AD DD), set the Type parameter to the LAP display name of the type of account you wish to create. Thanks to its user-friendly interface and bulk user actions, the effective Active Directory user management tool AD Manager Windows Plus makes it simple to manage thousands of Active Directory users. You must use an elevated command prompt to execute the Net-com command. These items are uniquely identified across the domain by their SIDS. This is often the Users container for the domain.
Learn more about Net-com command here:
https://brainly.com/question/29740672
#SPJ4
the function of an auxiliary view is to provide a two-dimensional drawing perspective of an object, which is ? the standard orthographic views, to show a feature of an object in true size and shape.
When a feature is not visible in the usual orthographic views, auxiliary views are frequently employed to help grasp its size, shape, or position.
What is auxiliaries?A representation of an object from a different viewpoint is used as an auxiliary view to support a primary view. When the primary view does not provide sufficient detail or does not provide all the information required to comprehend an item, auxiliary views are produced.
Is auxiliary memory part of the CPU?It is also known as auxiliary memory. In contrast to primary memory, it is non-volatile but not immediately available to the CPU.
To learn more about Auxiliary visit :
brainly.com/question/28528578
#SPJ4
"maneuvering the middle llc 2016 worksheets answer key pdf" what file is this?
"maneuvering the middle llc 2016 worksheets answer key.pdf" is the pdf file.
What is file?A computer file is a computer resource that stores data in a computer storage device and is recognized largely by its file name. Data may be written to a computer file in the same way that words can be written on paper. A file is a container for storing information in a computer system. Computer files include characteristics comparable to paper documents used in library and office files. In a business, file types dictate how files and organizational data are saved. A file type is often identifiable by its file extension and the apps that use it. Each saved file can have several file extensions but only one file type. A file format specifies how data in a file is stored.
Here,
"maneuvering the middle llc 2016 worksheets answer key.pdf" is the pdf download.
To know more about file,
https://brainly.com/question/14338673
#SPJ4
A feature on a new computer with Windows 8.1 preinstalled. When you take it out of the box and turn it on, you will be greeted with this last phase of Windows installation where you personalize the GUI and configure how you will sign in. Of course, it is also the last phase of a clean Windows 8.1 installation.
A delimiter is used by the split text-to-columns tool to do this type of activity, which is used to define where to split a text string.
A mark or symbol that indicates the start or end of distinct elements in a text, computer program, etc. is known as a delimiter. The comma is used as the delimiter in this line of code. A delimiter is used by the split text-to-columns tool to determine where to divide a text string. For defining the boundary between distinct, independent regions in plain text, mathematical expressions, or other data streams, a delimiter is a sequence of one or more letters. As a result, the split text-to-columns tool employs a delimiter to carry out the duty of indicating where to split a text string.
Learn more about Delimiter here:
https://brainly.com/question/30060046
#SPJ4
Which of the following cable types often includes a solid plastic core that keeps the twisted pairs separated?
A) Cat 5
B) Cat 6
C) Cat 5e
D) Cat 3
Option B is correct. Category 6 cable contains a strong plastic core that separates the twisted pairs and prevents the cable from bending excessively.
The twisted pairs of the Cat 6 cable are separated by a strong plastic core to prevent excessive cable bending. Computer networks capable of transmitting data at 1 Gbps, 1000 Mbps, or higher typically use Cat 6 cables. The following characteristics apply: The consists of four sets of copper wires, each used for data transmission.
The offers speeds up to 10Gbps, 250MHz bandwidth, and an extendable length of up to 100 meters. outperforms previous twisted pair cable variants in terms of better crosstalk and attenuation protection.
Ethernet networks such as 10BaseT, 100Base-TX, 1000Base-T, and 10GBase-T can use Cat 6 cables.
Know more about Ethernet here:
https://brainly.com/question/14622272
#SPJ4
an operating system is responsible for validating certificates used to secure communication. for windows, microsoft maintains a database of trusted root certificates issued by certificate authorities (cas). a root certificate is the original certificate issued by the ca. when a windows system opens a secure email or visits a secure website and encounters a new digital certificate, it requests microsoft's trusted root certificate, which is downloaded to the computer. the download happens seamlessly without the user's knowledge unless there's a problem. if windows cannot obtain the root certificate to validate the email or website, an error is displayed. where do you go in the windows operating system to view and delete root certificates?
To see and delete root certificates, you must access the certificate manager in the Windows operating system.
What does Windows operating system stand for?Microsoft created the operating system called Windows operating system that allows use to use your computer. The majority of new personal computers (PCs) come with Windows preloaded, making it the most widely used operating system in the world.
What distinguishing qualities does the Windows operating system have?Key features of Windows operating system include Start Menu, Task Manager, Taskbar, Cortana, File Explorer, MS Paint, Browser, Control Panel and more. Clean and clear GUI and support for Microsoft Office.
To learn more about operating system visit:
https://brainly.com/question/1092651
#SPJ4
the instructional notes in the tabular list take precedence over the instructional notes in the alphabetic index. question 1 options: true false
True. The instructional notes listed in the tabular list are more specific than the instructional notes in the alphabetic index.
What is tabular list?Tabular list is an organized way of presenting data in the form of columns and rows. It is a type of graphical representation used to display information in a clear and concise manner. Tabular lists are commonly used to display large amounts of data in an organized way, as well as to compare values between different categories. They can also be used to display information visually, making it easier to draw conclusions and make decisions. Tabular lists can be used to organize a variety of data, from financial records and customer feedback to scientific data and legal documents.
Therefore, any instructions listed in the tabular list should be followed first. The instructional notes in the alphabetic index should be used only if the instructions in the tabular list do not provide sufficient guidance.
To learn more about tabular list
https://brainly.com/question/14565472
#SPJ4
question 1 a data analyst wants to retrieve only records from a database that have matching values in two different tables. which join fun'ction should they use?
Using the SQL INNER JOIN function, records with matching values from two or more tables are combined to form a result table.
Essentially, a query is an inquiry or data request. Tell me how many Rolling Stones compilations were issued before 1980, or how many books on computer programming there are. To retrieve data from databases, we may utilize a common language. SQL is a fairly ubiquitous language (Structured Query Language). There are several diverse kinds, but once you grasp the principles, it's simple to change your enquiries. It's important to remember that databases store information in tables made up of informational rows and columns. The database fields are in the columns. They give the database instructions on what data to store, such as an album title. There are rows in the data. Look at this data in this case.
Learn more about Database here:
https://brainly.com/question/29359609
#SPJ4
question 5 as a marketer specializing in search engine optimization, you ensure that a website is well-organized and that it is easily crawled by search engines. this represents which seo task?
The process of positioning your website to appear higher on the a search engine results (SERP) in order to draw in more traffic is known as search engine optimization (SEO).
How many different SEO tactics exist?A SEO strategist can concentrate on one of three forms of SEO:On-page SEO: This type of SEO concentrates on the material that is already on website pages and on how to optimise it to raise the ranking of the website for particular keywords.Off-page SEO: This type of SEO concentrates on links that are made from other websites that point to the target website.
What techniques are used for optimization?The search and optimization of the transform parameters is done to maximize the degree of similarity between the distorted source image and the destination image.
To know more about marketer specializing visit:
https://brainly.com/question/3146024
#SPJ4
What is the purpose of entering time on timesheet in QuickBooks?
QuickBooks timesheets may be used to input your workers' hours worked and make payouts. Timesheets can also be used to generate an invoice for a customer.
What is QuickBooks?QuickBooks is a piece of accounting software created and offered by Intuit. QuickBooks products, which were first released in 1983, are primarily aimed at small and medium-sized enterprises and are available on-premises. QuickBooks enables you to keep track of financial activities including as income and spending, employee expenses, and inventory in real-time while also meeting tax responsibilities. QuickBooks automates the majority of the work for you, whereas Excel forces you to do everything from scratch. QuickBooks allows you to submit invoices, however Excel does not include any linked banking features. When working on an Excel sheet, you have infinite resources.
Here,
QuickBooks timesheets allow you to record your workers' hours worked and produce payouts. You may also utilize timesheets to construct an invoice for a customer.
To know more about QuickBooks,
https://brainly.com/question/27938333
#SPJ4
Dan, a technician at Acme Mfg, receives notice that the SOHO routers he supports are subject to a series of recently discovered vulnerabilities. Dan examines the router configuration files carefully and finds that all connections and settings are appropriately configured.
Settings are installed properly is The administrative password for the router should be changed.
In a WiFi router, what is the administrator password?While the wireless password is required to connect wireless devices to your wireless home network or hotspot, the router or admin password is used to access the router's web-based setup page for configuration or verification purposes.
Can a WiFi router be compromised?Your router may have been compromised and you are completely unaware of it. Hackers can compromise the security of your home Wi-Fi and potentially do a lot of damage to you by employing a method called DNS (Domain Name Server) hijacking.
To know more about router's visit:-
https://brainly.com/question/29583049
#SPJ4
given a list of names determine the number of names in that list for which a given query string is a prefix
Determine how many names in a list of names have the supplied query string as a prefix by using the given list of names.
function findCompletePrefixes(names, supposition):
count = [] for q in names, and 0 for the name in names
, if name
lower() does not equal q.lower() or name.lower ().
startswith(q.lower()): count + c.
append(c)
return count
If _name_ is "_main_": print(findCompletePrefixes(["steve", "stevens", "Danny", "steves", "dan", "john", "johnny", "joe", "alex", "alexander"]], ["steve", "Alex", "joe", "john", "dan"])
Traditionally, a string in computer programming is a collection of characters that can be either a literal constant or a type of variable. The latter can either have a fixed length or allow for element mutations (after creation). A string is normally regarded as a type of data and is frequently implemented as an array data structure made up of bytes (or words) that store a series of components, usually characters, using a character encoding. Other data types and structures that use sequences (or lists) of items can also be referred to as strings.
A variable declared to be a string may either cause memory to be statically allocated for a preset maximum length or, depending on the programming language and precise data type used, it may not.
Learn more about string here:
https://brainly.com/question/13088993
#SPJ4
Which of the following shows the number 6 when you type it in the Console (interactive mode) of Python:
You can immediately type your code into the Python interpreter in interactive mode. This is helpful for testing out quick bits of code or for writing things as you go.
What is python?Python is a general-purpose, high-level programming language. Its design philosophy prioritizes code readability and heavily employs indentation. [33]
Python has dynamic typing and garbage collection. It supports a number of programming paradigms, including structured programming, object-oriented programming, procedural programming, and functional programming (especially this). It is frequently referred to as a "batteries included" language because of its large standard library. [34] [35]
In order to replace the ABC programming language, Guido van Rossum developed Python in the late 1980s. Python 0.9.0 was released in 1991.
[36] Python 2.0, which was released in 2000, included brand-new features like list comprehensions, cycle-detecting garbage collection, reference counting, and support for Unicode.
Hence, You can immediately type your code into the Python interpreter in interactive mode.
learn more about Python click here:
https://brainly.com/question/26497128
#SPJ4
if i install a steam game into a portable drive, can i stick the drive in and play the game on any computer with steam without reinstalling the game??
Yes, you can. As long as you have the game installed to the portable drive, you can plug it into any computer with Steam and launch the game without having to reinstall it.
What is reinstall?Reinstalling is the process of completely wiping out the existing version of a software program or operating system from a computer and then downloading and installing a new version of the same program or operating system. It is often done in order to fix a problem with the existing version or to take advantage of new features that have been added to the new version. Reinstalling can also be done in order to increase the speed and performance of a system by removing any unnecessary files or applications that may have accumulated over time. Reinstalling is usually done via a system's installation disc, but it can also be done online.
To learn more about reinstall
https://brainly.com/question/29989277
#SPJ4
What does music mean to you? Is it a big part of your life, or is it just "there". Answer in at least two complete sentences.
Answer:
Music means a lot to almost everyone and plays a significant role in most people's lives. With all of the different genres, music encompasses a wide range of moods and emotions, and there is something for almost everyone.
Answer:
Music plays a crucial role in several people's lives. There is proof that music has helped benefit people's lives to be more positive, and some studies show that students that listened to music and meditated with music during school, had anxiety levels less than students who didn't get such an opportunity.
Explanation:
(I've read a paper somewhere for school for a health project abt stress and anxiety)
before writing a program you, must first? select one: a. design it b. write code c. correct logical errors d. test it
The correct response is a. design. Before writing a program you, must first design.
A design is a plan or specification for the creation of a system, an item, or the implementation of an activity or a process, or the outcome of that plan or a specification that takes the form of an item, process, or finished product. Designing refers to the process of producing a design. In some circumstances, the act of directly creating an object without a clear prior plan (such as in craftwork, some engineering, coding, and graphic design) may also be seen as a design activity. The design typically has to adhere to a set of objectives and restrictions; it could also take into account economic, socio-political, or functional factors; and it is anticipated to interact with a certain environment. Circuit diagrams, sewing patterns, architectural and engineering plans, and business process models are a few common types of designs.
Learn more about design here
https://brainly.com/question/1020696
#SPJ4