SQU IT Exit key terms

A finite, ordered set of unambiguous steps that takes input and produces a result, terminating after a limited number of operations. It must be correct, deterministic where required, and efficient enough for its intended input size.

A language-neutral, informal notation that describes the logic of an algorithm using structured English and control-flow keywords. It is easier to review and translate into any programming language than actual source code.

A diagram that represents the sequence of steps in a process using standard symbols: ovals for start and end, parallelograms for input and output, rectangles for processing, diamonds for decisions, and arrows for control flow.

The region of a program in which a declared name is visible and can be used. Local scope limits a variable to its block or function, while global scope makes it accessible throughout the program, raising risks of unintended modification.

The mechanism by which arguments are supplied to a function. By value copies the argument so the caller's data is protected; by reference passes the address so the function can modify the caller's original variable.

A technique in which a function solves a problem by calling itself on a smaller instance of the same problem. Every correct recursion needs one or more base cases that stop the self-calls and prevent infinite descent.

A measure of how the running time of an algorithm grows as the input size increases, usually expressed in Big-O notation. It describes the dominant growth trend and ignores constant factors and lower-order terms.

A formal notation describing an asymptotic upper bound on an algorithm's growth rate. Common classes include O(1) constant, O(log n) logarithmic, O(n) linear, O(n log n), O(n squared) quadratic, and O(2 to the n) exponential.

The total amount of memory an algorithm needs relative to input size, counting both the input storage and any auxiliary structures it allocates. Recursive algorithms also consume stack space proportional to recursion depth.

A linear data structure that follows last-in, first-out order: elements are pushed and popped only at one end, called the top. It supports function calls, undo operations, expression evaluation, and depth-first traversal.

A linear data structure that follows first-in, first-out order: elements are enqueued at the rear and dequeued from the front. Variants such as circular queues and priority queues serve scheduling and breadth-first traversal.

A sequence of nodes where each node stores data plus a pointer to the next node (and optionally the previous one). Insertion and deletion are cheap once the position is known, but random access requires traversal.

A structure that maps keys to values by computing a hash code that selects a bucket, giving average constant-time lookup. Collisions are resolved by chaining or open addressing, and a poor hash function degrades performance.

A binary tree in which every node's left subtree holds smaller keys and its right subtree holds larger keys. Search, insert, and delete take O(log n) time when balanced but degrade to O(n) when skewed.

A systematic way of visiting every node of a tree exactly once. Depth-first orders are pre-order, in-order, and post-order; breadth-first order visits nodes level by level using a queue.

A collection of vertices connected by edges, which may be directed or undirected and weighted or unweighted. Graphs model networks, maps, and dependencies, and support traversal by breadth-first or depth-first search.

A procedure that rearranges elements into a defined order. Common examples include bubble, insertion, selection, merge, quick, and heap sort, which differ in average time complexity, stability, and memory use.

A column or minimal set of columns whose values uniquely identify each row in a table. It must be unique and not null, and each table may have only one primary key, which other tables reference as a foreign key.

A column or set of columns in one table whose values must match a primary key value in another table, or be null. It enforces referential integrity between related tables.

The process of organizing tables to reduce redundancy and avoid update, insert, and delete anomalies. It proceeds through normal forms, typically first, second, and third normal form, each removing a specific class of dependency problem.

An operation combining rows from two or more tables based on a related column. Inner joins return only matches; left, right, and full outer joins also return unmatched rows padded with nulls.

A SQL function that summarizes many rows into a single value, such as COUNT, SUM, AVG, MIN, and MAX. It is often combined with GROUP BY to compute one result per group rather than for the whole table.

A transaction is a group of database operations executed as one unit. ACID properties require atomicity (all or nothing), consistency, isolation between concurrent transactions, and durability of committed changes after failure.

Techniques that keep simultaneous database transactions from interfering with each other. Locking and timestamp ordering prevent lost updates, dirty reads, and inconsistent analysis while preserving the isolation property of ACID.

A seven-layer conceptual framework for network communication: physical, data link, network, transport, session, presentation, and application. Each layer provides services to the layer above and uses the layer below.

The practical four-layer protocol stack of the Internet: network access, internet, transport, and application. IP handles addressing and routing, while TCP provides reliable ordered delivery and UDP provides fast connectionless delivery.

The procedure that opens a TCP connection: the client sends SYN, the server replies SYN-ACK, and the client sends ACK. It synchronizes sequence numbers and confirms both endpoints are ready to exchange data.

A 32-bit value that separates the network portion of an IPv4 address from the host portion. Combined with the address it identifies the subnet, and its length determines how many hosts that subnet can contain.

Symmetric encryption uses one shared secret key for both encryption and decryption and is fast. Asymmetric encryption uses a public key to encrypt and a matched private key to decrypt, enabling key exchange and digital signatures.

A one-way function that converts data of any length into a fixed-length digest. It verifies integrity because any change to the input produces a different digest; it is not encryption and cannot be reversed.

A digitally signed document that binds a public key to an identity, issued by a certificate authority the relying party trusts. It supports authentication and secure key exchange in TLS and prevents impersonation.

A process is a running program with its own memory space and resources. A thread is a smaller unit of execution inside a process; threads share the process memory, so they communicate cheaply but need synchronization.

The act of saving the state of one running process or thread and restoring the state of another so it can run. It enables multitasking but adds overhead because no useful user work happens during the switch.

A state in which two or more processes each hold a resource the others need and all wait forever. It requires mutual exclusion, hold and wait, no preemption, and circular wait; breaking any one condition prevents it.

A technique that gives each process an illusion of a large contiguous address space, mapped to physical frames by the memory management unit. Pages not in memory are moved to disk, causing page faults when referenced.

The structured phases a software product passes through: requirements, design, implementation, testing, deployment, and maintenance. Different models such as waterfall, iterative, and agile arrange and repeat these phases differently.

A documented statement of what a system must do and how well it must do it. Functional requirements describe behavior; non-functional requirements cover qualities such as performance, security, usability, and reliability.

A UML diagram showing actors outside the system and the use cases they perform, connected by associations. It defines system scope and externally visible functionality rather than internal logic or sequence.

A tree-structured programming interface that represents an HTML or XML document as objects. Scripts use it to read and modify elements, attributes, and styles, which is the basis of dynamic behavior on web pages.

The message exchange of the web: a client sends a method, URL, headers, and optional body, and the server returns a status code, headers, and body. Methods include GET, POST, PUT, and DELETE.

A protocol in which each request is independent and the server keeps no memory of earlier requests. HTTP is stateless, so applications add cookies or tokens to maintain continuity across requests.

A cookie is a small piece of data the browser stores and sends back to a site. A session is server-side state identified by a cookie or token, letting a stateless protocol remember a logged-in user.

An approach that makes one web page adapt its layout to different screen sizes using fluid grids, flexible images, and media queries. It avoids maintaining separate desktop and mobile versions of a site.

A project scheduling technique that identifies the longest chain of dependent tasks, which determines the shortest possible project duration. Any delay on the critical path delays the whole project.

A horizontal bar chart showing project tasks against a calendar timeline, with bar length representing duration. It displays start and end dates, overlaps, milestones, and progress at a glance.

The uncontrolled expansion of project requirements without matching adjustments to time, cost, or resources. It is managed through formal change control and clear baselined requirements.

A situation in which a professional's personal interest, financial or otherwise, could improperly influence decisions made on behalf of an employer or client. It must be disclosed and managed, not hidden.

A published set of principles guiding practitioner conduct, typically covering public welfare, competence, honesty, confidentiality, and avoidance of harm. Professional bodies use it as a benchmark for judging behavior.

Legally protected creations of the mind, including software, source code, designs, and documentation. Protection comes through copyright, patents, trademarks, or trade secrets, and using others' work without permission can infringe those rights.

A communication technique in which the listener concentrates fully, avoids interrupting, and confirms understanding by paraphrasing or asking clarifying questions. It reduces misunderstanding and builds trust within technical teams.

Planning and delivering project information to each audience in a form and frequency suited to its needs. It includes status reports, meetings, and escalation paths, and is essential for managing expectations.