Website and marketing terms beginning with D

Data controller

A data controller determines the purposes and means of processing personal information under the relevant framework. The role depends on the actual arrangement. A Jersey business should understand its responsibilities and supplier relationships rather than assuming that buying a platform transfers every decision to the provider.

Also called: controller

Data freshness

Data freshness describes how recently collected information has been processed and made available in a report. In Google Analytics, different reporting surfaces can update on different schedules, and recent values may change. For a Jersey business, record the report time and selected period, allow for processing and check the relevant definitions before treating today’s provisional figures as a final result.

Also called: analytics freshness

Data processor

A data processor handles personal information on behalf of a controller under the applicable arrangement. Not every supplier has the same role for every activity. Review what a website service actually does and document the appropriate responsibilities for the Jersey business’s data-handling workflow.

Also called: processor

Data retention

Data retention concerns how long information is kept and the reasons for keeping it. A Jersey business should connect that decision to the purpose and applicable requirements. Include relevant copies and supplier systems in the review rather than deleting one visible record and assuming every copy disappeared.

Also called: retention period

Data sampling

Data sampling uses a portion of a dataset to estimate results for a larger dataset. In Google Analytics, sampling can affect a query when it exceeds processing limits. For a Jersey business, inspect the report’s data quality information and record the sampled scope before comparing results or treating a small difference as a reliable change in performance.

Also called: analytics sampling

Data thresholding

Data thresholding withholds certain analytics results to reduce the risk of identifying individuals or inferring sensitive information from small groups. Google Analytics applies these thresholds automatically in relevant reports. For a Jersey business, check the data quality explanation and avoid interpreting a withheld row as zero activity, a failed campaign or proof that nobody completed a task.

Also called: analytics thresholding

Data URL

A data URL embeds resource data within the URL itself using the data scheme. It differs from a blob URL, which refers to a backing browser object. Review the representation and purpose in the feature, so an embedded preview or resource is given an accurate meaning instead of being assumed to be a separately hosted file.

Also called: data URI

Database

A database stores organised information that software can retrieve and update, such as products, bookings or account records. Different systems organise and access that information in different ways. A Jersey business should know which records its website needs, who can access them, and how they are backed up, maintained and recovered.

Also called: data store

Database autocommit

Database autocommit refers to automatic transaction completion for operations outside an explicitly maintained transaction, according to the database and client’s behaviour. It affects whether several statements are grouped together. Review the actual connection settings and transaction boundaries rather than assume a sequence of application statements always succeeds or fails as one unit.

Also called: SQL autocommit

Database commit

A database commit completes a transaction and makes its changes part of the committed database state. It differs from a Git commit that records source-code history. Check the actual result and transaction boundary; committing database changes does not by itself confirm an external payment, email delivery or customer acknowledgement.

Also called: SQL COMMIT

Database constraint

A database constraint defines a rule for stored data, such as requiring a value, preventing certain duplicates or checking a relationship. The actual database and enforcement settings matter. A Jersey business should review the intended rule and customer-facing error handling; valid stored data does not automatically establish that every business process or access decision is correct.

Database deadlock

A database deadlock occurs when transactions hold locks that other involved transactions need, leaving them unable to proceed without resolution. A database may abort a transaction to break the situation. Review the application’s error and retry handling; an aborted operation should not be reported to the customer as a confirmed business outcome.

Also called: SQL deadlock

Database index

A database index is a maintained structure that can help the database locate records efficiently for suitable queries. It adds storage and update work, so more indexes do not automatically improve everything. Review the actual query workload; this is a different concept from search-engine indexing.

Database join

A database join combines rows from tables according to a defined condition. It can connect customer records to their bookings for a report. The type of join affects which records appear, so confirm how missing relationships and repeated matches are handled before relying on the result.

Also called: SQL join

Database migration

A database migration changes the structure or organisation of stored data, sometimes alongside a software release. It needs a plan for existing records and application compatibility. Test the change with representative information and agree recovery steps before altering a live system that holds business commitments.

Also called: schema migration

Database query

A database query requests information from a database using the system’s supported language or interface. It can select, filter and combine records for a business task. Ask whether the application retrieves only the needed information and whether the result is checked against the intended workflow.

Also called: data query

Database rollback

A database rollback discards changes in the current transaction under the database’s supported transaction behaviour. It differs from restoring a backup or deploying an earlier website version. Review what was inside the transaction: rolling back database updates does not automatically reverse an action already completed in an external service.

Also called: SQL ROLLBACK

Database row lock

A database row lock coordinates supported concurrent operations on particular rows. Its effect depends on the lock mode and database. In PostgreSQL, row locks block relevant writers and lockers rather than ordinary reads. Review the actual transaction and wait behaviour instead of assume a row lock makes every query stop.

Also called: SQL row lock

Database savepoint

A database savepoint marks a position within a transaction so supported rollback can discard changes made after that point. It does not commit the earlier work as a separate completed transaction. Ask the maintainer to explain the intended failure handling and which operations the savepoint actually covers.

Also called: SQL SAVEPOINT

Database schema

Database schema can describe the structure of database objects; in PostgreSQL a schema is also a named namespace containing objects such as tables. The exact meaning depends on the system and conversation. Ask the developer which structure or namespace is changing and how the migration is checked.

Database transaction

A database transaction groups database operations into a defined unit of work. Supported transaction behaviour can commit the changes together or discard them on rollback. A Jersey business should review the actual boundaries, failure handling and concurrency rules; a database transaction does not automatically include an external payment, email or other service action.

Database upsert

A database upsert combines an insert attempt with supported conflict handling, which can update an existing row or perform no change. SQLite’s UPSERT responds to specified uniqueness conflicts. Review the actual database syntax, matching rule and permitted updates; an upsert does not automatically decide which customer or product record is the correct match.

Also called: SQL UPSERT

Database view

A database view gives a query a name that can be referenced in supported database operations like a table. It can provide a consistent interface to underlying data. Review the view definition and access arrangement; a convenient report view is separate from a copied backup or a guarantee that its data is available to every user.

Also called: SQL view

Datagram

A datagram is a separate unit of data carried by a datagram service, such as UDP. It differs from the byte-stream interface provided by TCP. The transport and application determine the relevant handling, so a sent datagram is separate from confirmed receipt or a completed business operation.

Datalist

The HTML datalist element supplies suggested values for an associated control. It is separate from a select menu: a control may accept another value that satisfies its validation. Review supported browser and accessibility behaviour before choosing it, and distinguish suggestions from a rule requiring an approved option.

Also called: data list element

DataView

DataView provides a JavaScript interface for reading and writing number types within a binary buffer. It supports specifying the relevant byte ordering for operations where applicable. It is a data view, separate from a database report or user-facing table. Review the actual representation and protocol rather than assume a readable value proves correct interpretation.

Also called: JavaScript DataView

Date get date

Date.getDate() returns the day of the month in local time, from one to thirty-one. It does not return a full date string or the day of the week. When reviewing a calendar feature, ask which parts are assembled and which time zone is used before approving the customer-facing appointment.

Also called: Date.getDate(), getDate()

Date get day

Date.getDay() returns the weekday in local time as a number from zero to six, with Sunday represented by zero. The day of the month uses a different method. Check the mapping used by an opening-hours or booking calendar so the number is translated into the intended weekday label.

Also called: Date.getDay(), getDay()

Date get month

Date.getMonth() reads the month in local time as a number from zero to eleven: January is zero and December is eleven. This convention matters when code feeds a calendar or report. Verify the conversion to customer-facing month numbers and names so the display does not shift a booking by one month.

Also called: Date.getMonth(), getMonth()

Date get time

Date.getTime() reads the timestamp of an existing JavaScript Date object in milliseconds since the start of 1 January 1970 UTC. It returns NaN for an invalid date. Check that the object represents the intended appointment and that the receiving system expects milliseconds before using its numeric value.

Also called: Date.getTime(), getTime()

Date get time-zone offset

Date.getTimezoneOffset() reports the host system’s local-time difference from UTC in minutes for the supplied date. Positive values mean local time is behind UTC. It does not retrieve the original offset written in an imported date string. Have the maintainer check the actual booking zone and conversion requirement.

Also called: Date.getTimezoneOffset(), getTimezoneOffset()

Date input

An HTML date input represents a calendar date without a time component. Its value uses a year-month-day format, while the displayed interface can vary with the browser and locale. Agree what the selected date means to the business and check the received information; choosing a date does not by itself confirm an appointment.

Also called: input type date

Date now

Date.now() returns the current timestamp in milliseconds since the start of 1 January 1970 UTC. A millisecond is one thousandth of a second. Confirm the unit before exchanging an order timestamp with another system: treating milliseconds as seconds gives the receiving application a completely different value.

Also called: Date.now()

Date parse

Date.parse() converts a date string into a timestamp, returning NaN when parsing fails. Non-standard formats can behave differently across browsers. Specify the accepted format and time-zone meaning for a booking import, rather than assume a familiar-looking numeric date will be interpreted consistently on every customer’s device.

Also called: Date.parse()

Date to ISO string

Date.toISOString() returns a date-time string in the standard JavaScript format with a Z suffix indicating UTC. Invalid dates raise a RangeError. For a booking confirmation, keep the stored instant and the customer’s displayed local time clear; a UTC string does not itself supply a named time zone’s scheduling rules.

Also called: Date.toISOString(), toISOString()

Date to JSON

Date.toJSON() normally represents a valid Date as a UTC date-time string and returns null for an invalid date. JSON.stringify() calls it automatically for Date objects. The receiving application must understand the agreed field format; parsing the JSON alone does not recreate a Date object or verify the customer’s intended appointment.

Also called: Date.toJSON(), toJSON()

Date UTC

Date.UTC() interprets supplied date and time components as UTC and returns a timestamp in milliseconds. Its month parameter starts at zero for January. Components outside their expected ranges can roll into other components, so the method should not be treated as complete validation of a customer’s chosen booking date.

Also called: Date.UTC()

Date-only value

A date-only value represents a calendar date without a clock time or time zone. Temporal.PlainDate documents this distinction in JavaScript’s supported Temporal arrangement. Keep date-only information separate from a booked instant; adding an assumed midnight and zone can change how another system interprets what was intended as a calendar date.

Also called: Calendar date value

Daylight saving time

Daylight saving time is part of some local civil-time arrangements, changing the applicable offset during defined periods. The rules are location- and date-dependent and can change. Have the maintainer review relevant booking cases using the actual maintained zone data rather than assume one fixed offset describes every future appointment.

Also called: DST

DDoS attack

A distributed denial-of-service attack uses traffic from multiple sources to disrupt a service’s availability. It is different from a slow page caused by a large image. Ask the hosting provider what protection and incident support apply to the actual service the business uses.

Also called: distributed denial of service

Dead-letter queue

A dead-letter queue holds messages that could not be processed according to the configured handling rules. It helps a maintainer inspect failures; it does not fix the underlying problem automatically. Define who reviews those messages, how sensitive information is handled and when an appropriate retry is allowed.

Also called: DLQ

Debugging

Debugging investigates the cause of unexpected software behaviour and checks a proposed fix. It requires a reproducible problem and relevant evidence. Keep diagnostic detail appropriate for the audience; customer-facing errors should be useful without exposing private records or internal secrets.

Decoded body size

Decoded body size is the resource payload size after removing content encodings in the browser PerformanceResourceTiming interface. It differs from the compressed delivered representation. Cross-origin timing restrictions can produce a zero value. Compare the correct fields under identifiable conditions rather than assume every displayed size refers to the same stage of a resource’s delivery.

Also called: decodedBodySize

DecompressionStream

DecompressionStream is a web interface that decompresses a stream through a supported compression format. It is a processing component within the larger exchange. Check the actual format and recovered output against the intended source; obtaining decompressed bytes is separate from confirming the file’s business version, completeness or suitability for the next application.

Also called: Decompression Stream interface

Dedicated hosting

Dedicated hosting supplies a server allocated exclusively through the relevant customer arrangement, rather than the same ordinary shared-hosting setup. It does not automatically include every management task. Review the service’s actual scope, application requirements and maintenance responsibility before treating dedicated hardware as a guarantee of website quality.

Deflate

Deflate is a lossless compressed-data format combining LZ77 and Huffman coding, defined in RFC 1951. Other formats and protocols can wrap its compressed data in additional structure. Ask the maintainer to identify the actual wrapper and receiver requirements rather than treat Deflate, Gzip and ZIP as interchangeable names for the same complete file.

Also called: DEFLATE compression

Delivery status notification

A delivery status notification reports relevant delivery information about an email message using the mail system’s notification arrangement. It can include recipient status and diagnostic details. Interpret what it actually confirms; a delivery report is separate from a person reading the message or completing the requested business action.

Also called: DSN

Dependency

A software dependency is a package or component another project relies on. It may support the build, the running application or both, and can introduce further dependencies. A Jersey business should keep a maintainable inventory and agree how version changes, compatibility, licences and relevant security findings are reviewed before release.

Also called: package dependency

Deployment

Deployment puts a prepared version of software or website files into an environment where it can run or be served. Building a site and deploying it are different steps. A release should include checks of important live pages and business journeys after the change reaches customers.

Also called: release deployment

Design system

A design system combines reusable design choices, interface components and guidance for applying them consistently. It can cover appearance, behaviour and common customer tasks. A Jersey business should understand which parts its website uses, who maintains them and how a change is checked across the pages that depend on them.

Design token

A design token names a reusable design value, such as a colour or dimension, so tools and components can refer to the agreed choice. It is different from an authentication token. Named values help maintain consistency, but the actual combinations still need usability and accessibility review.

Development dependency

A development dependency supports development or preparation tasks such as building and testing a project. The distinction affects installation arrangements. It can still matter to the released output, so document which tools the build needs instead of assuming the category means it has no maintenance or security relevance.

Also called: devDependency, devDependencies

Device pixel ratio

Device pixel ratio expresses the relationship between physical display pixels and CSS pixels. It helps explain why an image shown in a modest layout box may need a larger pixel source on some screens. Review the actual displayed size and browser-selected image; doubling every file is not a complete image-delivery plan.

Also called: DPR

DHCP

DHCP means Dynamic Host Configuration Protocol. It lets a supported service provide devices with IP addresses and relevant network configuration. It is separate from DNS, which resolves names. The network administrator should maintain the actual assignment arrangement; a device obtaining an address does not prove every website or application is reachable.

Also called: Dynamic Host Configuration Protocol

Digital product

A digital product is delivered through digital content or access, such as a downloadable file, rather than a physical parcel. Review the customer’s delivery instructions, access requirements and support process. Completing payment and successfully receiving usable access are separate outcomes to check.

Digital signature

A digital signature is cryptographic evidence used to check a message or document against a signing key and the relevant verification process. Its trust depends on key protection and the verifier using the appropriate trusted key. For a Jersey business, establish what was signed and what verification means before treating a valid result as approval, confidentiality or a completed transaction.

Also called: cryptographic signature

Dimension cardinality

Dimension cardinality is the number of distinct values a dimension can take in the relevant data. It helps explain the size of an analytics breakdown. Ask which dimension and period the analyst means, and keep its purpose clear before interpreting a large set of different values as a useful business comparison.

Also called: analytics cardinality

Disabled field

The HTML disabled attribute makes a supported control unavailable for editing and focus, and excludes it from form submission. A visible disabled detail should not be assumed to reach the receiver. Have the maintainer explain how the workflow obtains any necessary information, and keep receiving checks separate from the control’s appearance.

Also called: disabled attribute

Disaster recovery

Disaster recovery is a planned process for restoring important systems after a serious disruption. It combines recovery information, responsibilities, dependencies and tested procedures. A Jersey business should identify the website functions that matter most, how much interruption or data loss it can tolerate and how customer commitments will be preserved during recovery.

Also called: DR

Disclosure control

A disclosure control shows or hides a section of content and communicates whether it is expanded. It can keep optional detail manageable, but important information should remain easy to find. Check the control’s label, expanded state and keyboard behaviour in the actual website.

Also called: show hide control

Discount code

A discount code applies a configured offer when the customer enters an eligible code. Its scope, limits and combination rules depend on the shop. Review representative products and baskets, show the resulting total clearly and check that the offer wording matches the actual conditions.

Also called: promo code

Discussion guide

A discussion guide structures a research session with introductions, topics, prompts or task descriptions. It helps the researcher remain consistent without preventing relevant follow-up. Try the wording beforehand and avoid prompts that give away an answer, especially when the aim is to learn how a person understands a website.

Also called: interview guide

Dispatch event

EventTarget.dispatchEvent() sends an initialized event to a target and invokes applicable handlers synchronously under the normal event-flow rules. It is a programmatic event operation. Review the feature’s actual response and business result separately, especially where a demonstration of a synthetic event is being used as evidence about a real customer interaction.

Also called: EventTarget.dispatchEvent()

Distributed trace

A distributed trace records the path of work across operations or services using related spans. It can help a maintainer understand where a request spent time or failed. Its usefulness depends on instrumentation and context; a trace is evidence for an investigation rather than an automatic explanation of every problem.

Also called: request trace

Distribution group

A distribution group delivers messages sent to a group address to its configured recipients. It differs from everyone working in one shared mailbox. Review membership, permitted senders and reply behaviour before publishing the address, and update the recipients when staff responsibilities change.

Also called: distribution list

DKIM selector

A DKIM selector identifies the relevant public-key lookup used when verifying a DKIM email signature for a domain. It lets a signing arrangement distinguish keys. Use the mail provider’s actual selector and published record, and review key changes through the supported process instead of copying an unrelated example.

DNS

DNS, the Domain Name System, helps devices find services connected to a domain name.

Also called: Domain Name System, DNS settings

DNS apex

The DNS apex is the name at the top of a particular DNS zone, such as the zone’s main domain name. Provider interfaces may call it the root domain or represent it with an at sign. Check the actual provider’s record options; an apex configuration is distinct from a www subdomain configuration.

Also called: Zone apex

DNS cache poisoning

DNS cache poisoning involves false DNS information entering a cache and influencing subsequent answers. It can misdirect clients that rely on that data. DNSSEC validation addresses authentication of appropriately signed DNS data, but a website still needs maintained connection and application controls. Investigate an actual incident with the responsible DNS and security providers.

Also called: DNS poisoning

DNS delegation

DNS delegation assigns responsibility for a part of the DNS namespace to the relevant authoritative nameservers. A subdomain can have its own administration through this arrangement. Record the delegated name and responsible provider; delegation is separate from an HTTP redirect and does not transfer website content or application permissions.

DNS lookup

A DNS lookup requests information about a name, such as its address records, through the relevant DNS resolution process. A successful lookup is separate from a completed website visit or application task. Record the queried name, record type and resolver when using a lookup result to investigate a business website issue.

Also called: DNS resolution

DNS over HTTPS

DNS over HTTPS, or DoH, sends DNS queries and responses through an encrypted HTTPS connection to a compatible resolver. It protects that lookup connection but does not make all browsing anonymous or replace DNSSEC validation. A Jersey business should review the chosen resolver, device settings and any managed-network requirements.

Also called: DoH

DNS propagation

DNS propagation is a common description for the period when different systems may see old or new DNS answers after a change. Caching and record settings are important factors. Test your Jersey website and email from more than one connection rather than relying on a universal “24 hours” rule.

DNS record

A DNS record is a typed entry associating a name with information used by DNS. Its fields include the name, type, caching lifetime and relevant data. Different types serve different purposes, so review the record required for the actual website or email service instead of treating every entry as an address.

Also called: DNS resource record

DNS resolver

A DNS resolver handles requests to look up names and obtain relevant DNS information. A recursive resolver can query other servers and reuse cached answers. For a Jersey business, understanding this role helps explain why a record change may appear differently across connections and why DNS checks should identify the actual source.

Also called: recursive resolver

DNS zone

A DNS zone is an area of the DNS namespace administered as a unit. It can include the main name and relevant subdomains, while delegated subdomains may be maintained elsewhere. Record the actual zone owner and provider before a change; a domain name and its DNS zone are related concepts with different administrative roles.

DNSKEY record

A DNSKEY record publishes a public key used in DNSSEC authentication. A validating resolver can use the relevant key to check signatures on DNS record sets. The published public key is distinct from private signing material, which needs protection. Have the DNS provider maintain the actual signing arrangement.

DNSSEC

DNSSEC means Domain Name System Security Extensions. It uses digital signatures so a validating resolver can check the origin and integrity of DNS data. It does not encrypt a DNS lookup or prove a business is trustworthy. A Jersey website owner should confirm who maintains signing and the domain’s chain of trust.

Also called: Domain Name System Security Extensions

DNSSEC validation

DNSSEC validation checks relevant signed DNS data and its authentication path using the resolver’s trust arrangement. It is separate from encrypting the query connection. If a provider reports a validation failure, retain the exact name and diagnostic evidence and ask the DNS maintainer to review signing and delegation.

Document chunking

Document chunking divides larger content into smaller pieces for processing or retrieval. A useful chunk should retain enough context to be understood, such as its subject and relevant qualification. Chunking differs from chunked HTTP transfer. Check the resulting passages against real customer questions rather than choose one size for every document.

Also called: RAG chunking

Document fragment

A DocumentFragment holds a segment of DOM structure outside the active document tree. Changes made there do not directly change the active document. It can support preparing content before insertion, while the business should still review the eventual visible information and customer action; a prepared fragment is separate from the complete rendered experience.

Also called: DocumentFragment

Document visibility state

The Document visibilityState property identifies the document’s visible or hidden state; visible can mean only partly visible in a foreground tab. It does not establish attention to a particular element. Review any dependent feature behaviour and keep the state separate from claims that a visitor read information or completed a business action.

Also called: document.visibilityState

DOM

The DOM represents a document as objects that software can inspect and change. Browser scripts can use it to update content or react to controls. A visual update should also remain understandable to people using assistive technology, especially when important results change without a new page loading.

Also called: Document Object Model

DOM parse from string

DOMParser.parseFromString() parses supported HTML or XML input into a Document using the selected content type. That representation is separate from a later active-page insertion. Review the expected structure, relevant parse errors and actual content-handling safeguards before treating supplied markup as approved information for the customer-facing feature.

Also called: DOMParser.parseFromString()

Domain authority

Domain authority is a third-party score intended to estimate aspects of a website’s search competitiveness. It is not a Google ranking score. Different providers calculate different metrics. Treat it as one imperfect comparison tool, not a target worth chasing at the expense of useful Jersey business content.

Also called: DA

Domain name

A domain name is the address people use to reach an online service, such as example.je.

Also called: web address, domain

Domain name vs hosting

A domain name is your online address; hosting is the service that makes your website available. They can come from different suppliers. A Jersey business can keep its .je address while moving hosts, provided its domain registration and DNS records are managed correctly.

Also called: domain versus hosting

Domain registrar

A domain registrar handles domain registration and renewal for customers. It may also sell hosting or email, but those are separate services. Keep the account and recovery details under the business’s control, and check the arrangements for moving your .je domain if you change supplier.

Also called: registrar

Domain renewal

Domain renewal maintains a registered domain under the applicable registry and registrar arrangements, commonly through payment for a further period.

Also called: domain expiry, domain expiration

DOMContentLoaded

DOMContentLoaded signals that the document has been parsed and the relevant deferred scripts have executed; it does not wait for every image and other resource to load. Keep the readiness condition clear in the feature. A document event should not be expanded into a claim that every page resource or customer task is complete.

DOMParser

DOMParser turns an HTML or XML input string into a browser Document that scripts can inspect. Parsing creates a document representation; it does not establish that the content is trusted or suitable for the visible page. For a Jersey business, review the input source, expected structure and handling safeguards before approving the information customers will see or use.

DS record

A DS record means Delegation Signer record. In DNSSEC it links the authentication chain across a zone boundary by referring to a child zone’s DNSKEY using a digest and related information. Its maintenance matters during provider changes. Ask the responsible registration and DNS providers to coordinate the actual trust transition.

Also called: Delegation Signer record

Duplicate content

Duplicate content is substantially similar content available at more than one web address. It may happen through URL variations or copied pages. Search engines may choose one representative version. Review redirects and canonical signals rather than assuming every repeated paragraph causes an automatic penalty.

Dynamic website

A dynamic website can generate content based on information such as a database, account or request. Shops and booking systems often use dynamic features. That flexibility needs appropriate maintenance and access controls. The label alone does not decide whether a website is faster, safer or better for a Jersey business.

Also called: dynamic site