Postgresql PGCES-02 Exam Prep
PGCES-02 PostgreSQL CE 8 Silver (Page 6 )

• Domeny tworza restrykcjony razem z typem. Wykorzystujesz je w kolumnach, aby miec spójna walidacje danych w wielu miejscach.
• To nie jest pelny niestandardowy typ z wlasnym input/output funkcjonowaniem. Aby stworzyc typ z wlasnym I/O i operacjami, uzylbys CREATE TYPE (lub rozszerzen w C). Domeny to uproszczona forma ograniczen na istniejacy typ.

• CREATE DOMAIN positive_int AS integer NOT NULL CHECK (VALUE > 0);
• CREATE TABLE orders (id serial, qty positive_int);

• latwo wymuszaja wspólne reguly dla wielu kolumn/naglówków,
• zmiana regul w jednym miejscu (domena) automatycznie wplywa na wszystkie kolumny ja uzywajace.

• Co to znaczy: transakcje zachowuja sie tak, jakby byly wykonywane jeden po drugim. Dzieki temu nie ma brudnych odczytów, niepowtarzalnych odczytów ani phantom reads.

• Implementacja: PostgreSQL uzywa SSI (Serializable Snapshot Isolation). W praktyce oznacza to, ze jesli wykryje konflikt miedzy transakcjami, jedna z nich zostanie zakonczona bledem “serialization failure” i trzeba ja ponowic.

• Zalózmy tabele orders(customer_id int, amount int).

• Transakcja T1:

• Transakcja T2, równoczesnie:

• T1 ponownie wykonuje to zapytanie:

• Outer packet: 10.5.1.1 > 52.165.16.154
• IPv4 protocol field: 41, which indicates IPv6 encapsulation
• Inner packet: IPv6 traffic between 2001:... addresses

• MAC address spoofing: Changes Layer 2 addressing; it does not explain the IPv6-in-IPv4 structure.
• Steganography: Hides data inside files or media, not visibly in a tunneled protocol.
• Broken encryption: No evidence of encryption being cracked.
• On-path sniffing: Involves intercepting traffic, not sending data to an external host.

Correct sequence

1. Merge Sales_Region with Sales_Manager using an inner join

1. Merge Region_Manager with Manager using an inner join

1. Merge Sales_Region and Region_Manager using a right join as a new query

• Information sources: Collect security-related data, such as network packets, system logs, audit records, or application events.
• Analysis: Examines the collected data to identify suspicious activity, attacks, or policy violations.
• Response: Takes or recommends action, such as generating alerts, logging the event, or supporting a protective response.

DAX 
Blue Sales = 
CALCULATE( 
    [Total Sales], 
    KEEPFILTERS('Product'[Color] = "Blue") 
)

• CALCULATE evaluates [Total Sales] after applying an additional filter.
• 'Product'[Color] = "Blue" restricts the calculation to blue products.
• KEEPFILTERS ensures the existing filter context is preserved. For example, filters for year, region, or customer remain active. If Color is already filtered, the blue condition is applied as an intersection rather than replacing the existing filter.
• Avoid ALL, because it removes filters and would not maintain the existing context.

• Set credit quotas for an account or individual virtual warehouses.
• Define monitoring intervals.
• Trigger actions when usage reaches thresholds, such as sending notifications or suspending a warehouse.
• Help control unexpected warehouse spending.

• Account Usage: Provides historical usage and billing data; it does not enforce credit limits.
• Warehouse Limit Parameter: Not the Snowflake object used for account-wide credit controls.
• Credit Consumption Tracker: Not a standard Snowflake object.

• B: Extending credit to customers increases receivables, so more cash is tied up in working capital.
• C: Replacing obsolete inventory does not reduce the overall inventory investment; it simply changes its composition.
• D: Paying suppliers earlier reduces payables. This uses cash and therefore increases the funds tied up in working capital.

• STP elects the switch with the lowest Bridge ID as the root bridge.
• The Bridge ID consists mainly of bridge priority + MAC address.
• If multiple switches have the same priority, the switch with the lower MAC address is preferred.
• STP bridge priority values are configured in increments of 4096, such as 0, 4096, 8192, and so on. 32768 is the standard default value.

• netstat -tuln can show listening TCP ports.
• If the web service is not listening, or is bound only to 127.0.0.1, remote browsers cannot connect even though the server responds to ping.

• traceroute: Tests the path to the server, but ping already confirms basic reachability.
• tcpdump: Useful for detailed packet analysis, but it is more appropriate after checking whether a service is listening.
• arp: Helps troubleshoot local IP-to-MAC resolution, not an application-layer web connection.

• Wireshark captures packets and allows you to examine their contents, potentially revealing usernames and passwords sent without encryption.
• Netcat creates network connections and can send or receive data, but it is not primarily a packet-analysis tool.
• Nessus scans for known vulnerabilities and configuration issues; it generally would not prove that credentials are visible in transit.
• Nmap performs network discovery and port/service scanning, not detailed packet-content inspection.

• Minimum
• Maximum
• Average
• Count
• Null/empty values
• Distinct values

• Enable column profile
• Enable details pane
• Show column profile in details pane

• C — Create a form extension and implement validation

• D — Use Chain of Command (CoC) with a form extension class

• A: Not expanding would increase its dependence.
• B: More business from the same corporation would make dependence worse.
• D: Passing work to other minority businesses does not solve its own dependence.
• E: The passage does not suggest that it can force or influence the corporation to give work to others.

• You can configure different pre-shared keys for different device groups.
• All cameras could use one key.
• All scanners could use another key.
• Each key can be associated with an appropriate role or access policy.

CIMA P3 topics

• IT governance and systems strategy
• Systems development and implementation
• Change and project governance
• Strategic and business risk

• A — Plan for new systems: The committee should help identify and prioritise systems requirements and ensure planned systems support organisational needs.
• D — Consider competitive issues: New information systems may affect Y’s competitive position, service quality and efficiency. These strategic implications should be considered.
• E — Ensure the system meets company goals: This is a key governance responsibility. The committee should ensure the project remains aligned with Y’s objectives and delivers business value.

• B — Develop new systems: Detailed system development should be performed by IT specialists and project teams, not the steering committee.
• C — Manage the project: The project manager should handle day-to-day project management. The steering committee should provide oversight, challenge and key decisions, rather than manage daily activities.

• Amazon S3 as the origin for static content
• Application Load Balancer (ALB) as the origin for dynamic content
• Amazon Route 53 configured to point the company’s domain name to CloudFront

• /static/* ? S3 origin; cache content at edge locations
• Dynamic paths such as /api/* ? ALB origin; forward requests to the EC2 application

• D — Managers focus on keeping costs low in the short term to maximise profits.

• E — Managers are given incentives to meet or undercut budgets.

• F — Managers delegate responsibility simply to reduce their workload.

• A — Capacity: The system must handle all current records and anticipated future records. A system that cannot cope with volume will quickly become ineffective.
• C — Accuracy: Academic records are critical, so the new system must be at least as accurate as the existing system and comparable systems. Poor accuracy could cause serious administrative and reputational problems.
• D — Integration: Linking with the university’s financial systems supports consistency and avoids duplicate data entry, especially for registration, deregistration and fee-related transactions.

• B — Parallel running: This is a useful implementation and risk-control technique, but it is not an essential feature of the system itself. It may also be expensive and time-consuming.
• E — Internet access for all information: This creates significant confidentiality and security risks. External access might be needed for selected services, but unrestricted access to all information is not essential and would be inappropriate for student records.

• Prevention costs: Avoiding defects, such as staff training and improved product design. The company has invested in these.
• Appraisal costs: Detecting defects before products reach customers, such as inspection and testing. The planned batch sampling has not been implemented.
• Internal failure costs: Correcting defects found before delivery.
• External failure costs: Dealing with defects after delivery, such as refunds, replacements, complaints and lost sales.

• Controlar o fluxo de dados entre S3 e SageMaker;
• Aplicar regras de segurança por meio da VPC;
• Reduzir a exposição dos dados;
• Permitir acesso privado ao bucket do S3.

• Amazon Inspector: avalia vulnerabilidades, mas não gerencia o fluxo de dados.
• Amazon Macie: ajuda a descobrir e proteger dados sensíveis no S3, mas não cria a conexão com o SageMaker.
• S3 Glacier Deep Archive: é uma classe de armazenamento para arquivamento, não uma solução de conectividade.

• Accept terms of use
• Enter a temporary code or credentials
• Provide basic registration information

• Enterprise authentication — Authenticates organizational users, often with centralized identity services; it is not specifically designed for temporary guest access.
• Ad hoc network — A temporary device-to-device network, not an authentication process.
• WPA3 — A wireless security standard. It protects Wi-Fi access but does not provide the web-based temporary access workflow described here.

• /27 (255.255.255.224)

• /26 (255.255.255.192)

• /25: Creates only 2 subnets, not 3
• /28: Provides only 14 usable hosts per subnet

• Vulnerability scanner: Identifies technical weaknesses in systems, applications, or devices.
• Penetration test: Simulates attacks to determine whether vulnerabilities can be exploited.
• SCAP (Security Content Automation Protocol): Uses standardized formats and protocols for automated vulnerability, configuration, and compliance checks.
• Illumination tool: Maps and analyzes broader supply-chain exposure and third-party risk.

• Help the team identify the root causes of delays.
• Empower the team to improve its workflow and practices.
• Facilitate removal of impediments.
• Avoid directing the team toward a solution without its involvement.
• Protect quality and sustainable delivery rather than simply accelerating everything.

• A: An impediment log may help, but merely recording problems does not empower the team to solve them.
• B: Directing the team to solutions conflicts with self-management.
• C: Adding impediments to the product backlog may incorrectly treat internal obstacles as product features and delays their resolution.

• Case Assignment Rules normalmente são avaliadas quando o caso é criado. Elas podem ser executadas novamente em uma edição somente se o usuário marcar “Assign using active assignment rules”; isso não acontece automaticamente apenas porque o caso foi fechado.
• Portanto, criar uma regra de atribuição não corrige os centenas de casos já fechados e não garante, por si só, que um caso será transferido antes de ser fechado.

• B — Usar uma ferramenta de dados: corrige os registros históricos já existentes, atualizando o Owner.
• D — Criar uma regra de validação: impede que um caso seja fechado enquanto ainda pertence a uma fila. Exemplo conceitual: se Status = Closed e o proprietário for uma fila, bloquear o salvamento.

• The type of change: standard, normal, or emergency
• The risk, impact, and complexity
• The change model being used

• A standard change may be pre-authorized through its change model.
• A normal change may require assessment and approval by an appropriate change authority.
• An emergency change may be authorized by an emergency change authority, often using an expedited process.

• Change authorities are not only needed for emergency changes.
• They are not assigned only when a change is deployed.
• They are not only required for normal changes.

• Asynchronous inference is designed for applications that submit individual inference requests, place them in a queue, and retrieve results later. It is useful when requests may take a long time or when traffic is intermittent.
• Batch transform is designed specifically to run inference over an entire large dataset stored in Amazon S3 and produce an output dataset.

• Large dataset/offline processing ? Batch transform
• Large or slow individual requests processed later ? Asynchronous inference

Recommended process

1. Access each switch’s terminal.
2. Use help to identify available commands.
3. Use the MAC table command, such as:

text 
   show mac-address-table

1. Use VLAN information, such as:

text 
   show vlan

1. Use interface information, such as:

text 
   show ip interface brief

1. Record each device’s:

• The product is already in production.
• The organization is examining the product’s functions and cost drivers.
• The objective is to reduce cost without reducing perceived value or required quality.

• Kaizen costing focuses on continuous, usually incremental, cost reductions during the manufacturing stage. It is not specifically the systematic examination of a product’s functions.
• Standard costing compares actual costs with predetermined standards; it is a control technique, not a product redesign method.
• Process innovation concerns developing significantly improved production processes, rather than analysing the product’s functions and value.

• A — Technical review by business owner: A business owner may approve the business impact, but a technical review is normally performed by technical personnel.
• C — Cost-benefit analysis after implementation: Cost-benefit analysis should occur before implementation to support the approval decision.
• D — Business continuity testing: This can be appropriate for major changes, but it is primarily part of business continuity and disaster recovery planning—not a universal change-management activity.

• True positive: The scan reports a vulnerability that really exists.
• False positive: The scan reports a vulnerability that does not exist.
• True negative: The scan correctly reports no vulnerability.
• False negative: The scan fails to detect a vulnerability that is actually present.

• A — If there is no demand, there should be no production.

• B — Not all sales equal profit.

• C — Stocking up on inventory is bad for business.

• D — All costs, except materials, are considered fixed.

• E — Departments should operate at full capacity regardless of bottlenecks.

• Sustainability
• Performance efficiency
• Reliability

• Allow the team to identify the causes of delays.
• Encourage improvements to processes, tools, and collaboration.
• Help remove impediments without dictating solutions.
• Protect quality and maintain a sustainable pace.

• A: An impediment log may help track issues, but merely recording them does not resolve the root causes.
• B: Directing teams toward solutions conflicts with the agile principle of a self-managing team.
• C: Adding impediments to the product backlog may delay their resolution and incorrectly treats them as product features.

• NAT traversal: Helps WAN Edge, vSmart, and vManage devices discover how to reach one another through NAT.
• Initial orchestration: Authenticates and introduces devices when they first join the SD-WAN fabric.
• Connection brokering: Provides information that allows devices to form their required control connections, after which the vBond is generally not in the data path.

• WAN Edge: Forwards user traffic and forms secure tunnels.
• vSmart: Controls the overlay control plane and distributes routes and policies.
• vManage: Provides centralized management, configuration, and monitoring.

• desktopwidth:i:1280
• desktopheight:i:1024

• Connection information: Controls connection-related settings, not the desktop resolution.
• Scaling plan: Controls when session hosts start, stop, or scale based on demand.
• Session behaviour: Controls behavior such as disconnect or logoff handling.
• Display settings: Specifically controls RDP display properties, making it the appropriate choice.

• Business risks
• Potential financial, operational, legal, or reputational impact
• How governance reduces risk to organizational objectives
• How much risk the organization is willing to accept

• Maintain head office control: Transfer pricing generally supports decentralisation rather than direct head-office control.
• Establish centralised decision making: This conflicts with divisional autonomy.
• Develop a top-down culture: Transfer pricing is intended to support empowered divisions and goal congruence, not impose purely top-down management.

• Suspended an operator who refused to use unsafe equipment.
• Paid another operator a bonus for using it.
• Prioritised short-term productivity over employee safety.

• A — Management is not particularly concerned with managing risks.

• B — Employees will perceive that management does not care about health and safety risks.

• C — The factory’s safety record is likely to be poor.

• Error correction (ECC): Improves data reliability but does not maximize bandwidth.
• RAM voltage: Increasing voltage may affect stability or speed, but it is not the primary method for increasing module bandwidth.
• Physical module size: Refers to the capacity or form factor of the RAM, not its data-transfer bandwidth.

• Configure row-level security (RLS) using the sales region and the HR manager’s identity.
• Publish the reports and datasets through a Power BI app.
• Grant the HR managers permission to use the app, but do not add them as workspace members.
• App users can view and interact with reports while RLS limits them to their region.
• They cannot modify the report layout because they do not have workspace editing permissions.

• Adding them to the workspace gives them workspace permissions that may allow report or dataset changes, depending on the assigned role.
• Creating copies is unnecessary and creates maintenance and security problems.
• Hosting datasets and reports in different workspaces does not, by itself, provide the required controlled access.

• Orders contains order-level information, such as the order date.
• Order Line Items contains the products, quantities, and line amounts associated with each order.
• Merging them on the order key, such as OrderID, places the order date alongside each line item. This allows you to calculate total order value and analyze it over time.
• Product attributes can remain in the Products table and be related to the resulting line-item table through ProductID.

• Merging line items with products addresses product attributes but does not first provide the order-level date and value needed for time analysis.
• DAX calculated columns or lists add unnecessary model complexity.
• Calculating order counts is not the first requirement and does not combine the required order and line-item data.

• The message came from the claimed sender (authentication)
• The message was not altered (integrity)
• The sender cannot easily deny sending it (non-repudiation)

• Attackers can send unsigned phishing emails.
• Attackers may compromise a legitimate account and send signed malicious emails.
• Users may still be tricked by a validly signed message.

• Data only needs to be current at 7 AM each day, so scheduled refresh is sufficient.
• Import mode provides the fastest report interaction because data is stored in Power BI’s in-memory engine.
• It supports row-level security (RLS), including the USERNAME() filter.
• You can limit the imported data to the current year and previous three years to reduce model size.
• DirectQuery would generally provide slower visual response times and is unnecessary here.
• Dual is mainly useful in composite models where some tables use DirectQuery and others use Import. That is not required by this scenario.
• Live connection is not appropriate because you are creating the semantic model.

• A: Concerns task scheduling and avoiding missed runs, not directly sizing the warehouse.
• B: The amount of data in a stream alone does not reliably determine compute needs; the SQL processing is what matters.
• D: A multi-cluster warehouse addresses concurrency, not the compute size needed for one task execution.

• An active relationship is used automatically when filters are evaluated. An inactive relationship does not propagate filters unless explicitly activated in DAX, so it would not reliably enforce the required security behavior.
• Apply security filter in both directions allows RLS filters to propagate across the relationship in both directions. This ensures that bidirectional filtering respects the RLS rules applied to both tables.
• Assume referential integrity is unrelated to RLS. It is mainly a DirectQuery optimization that allows Power BI to use an inner join when matching keys are guaranteed to exist.
• The relationship must therefore be active, with security filtering enabled in both directions.

• Keep earlier prompt versions.
• Identify the last version that produced acceptable output.
• Restore it as a baseline.
• Make small, controlled changes—ideally one significant change at a time.
• Test the output after each change.

• A: Discards useful information about what worked.
• B: Large simultaneous changes make it difficult to identify the cause of problems.
• D: Accepts output that does not meet the requirements.

• Link-local — FE80::/10; valid only on the local link/subnet and not routed by routers.
• Multicast — FF00::/8; identifies a group of interfaces rather than a private address range.
• Global unicast — 2000::/3; publicly routable IPv6 addressing.