Layered Architecture Overview

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Questions and Answers

Match the following layers in the architecture with their responsibilities:

Presentation Layer = Handles user interface and browser communication Application Layer = Executes business rules associated with requests Domain Layer = Hosts the business logic not specific to use-cases Infrastructure Layer = Manages read/write operations for domain entities

Match the following terms with their descriptions:

Domain Model = Represents the data and behavior in the domain layer Application Logic = Orchestrates implementation of use-cases Fake Implementations = Used in testing to provide known responses Business Rules = Guidelines for processing specific requests

Match the following concepts with their relevant aspects:

Presentation Layer = Exposed to the end user Application Layer = Separates interfacing layers for clarity Domain Services = Works on multiple domain entities Accessor Layer = Provides information to the logic layer

Match the following components with their purposes:

Application Layer = Manages orchestration of business actions Domain Logic = Operates through services for complex behaviors Testing Layers = Facilitates easier and faster testing Infrastructure Layer = Interacts with persistence mechanisms Signup and view all the answers

Match the following roles with their functionalities:

Entities = Exposes both data and behavior Fake Implementations = Simplifies testing by replacing real layers Domain Services = Groups related behaviors across entities Application Logic = Determines information needs for problem-solving Signup and view all the answers

Match the following SQL commands with their functions:

INSERT = Insert data into a table UPDATE = Delete records from a database table DELETE = Update existing data within a table SELECT = Retrieve and work with data Signup and view all the answers

Match the following database components with their descriptions:

Table = To store data View = Project data in a desired format from one or more tables LocalDB = On-demand managed instance of SQL Server Database = Organized collection of data Signup and view all the answers

Match the following attributes of LocalDB with their features:

Developer oriented = Managed instance of SQL Server engine Automatic startup = Can turn on when needed No configuration needed = Reduces complexity for development Minimal files utilized = Streamlined access without overhead Signup and view all the answers

Match the following types of SQL languages with their purposes:

Data Manipulation Language (DML) = Retrieve and manipulate data Data Definition Language (DDL) = Define database structures Transaction Control Language (TCL) = Manage transactions Data Query Language (DQL) = Perform queries on the data Signup and view all the answers

Match the database concepts with their characteristics:

Embedded database = Acts within a small application Local database = Keeps access local Server database = Requires configuration for full setup Relational database = Organizes data into tables Signup and view all the answers

Study Notes

Layered Architecture

Presentation layer is responsible for user interface and browser communication, interacting directly with the user.
Application logic layer coordinates application activity, manages application task progress without business logic, and communicates with the presentation layer.
Domain layer contains information about the business domain, use cases, and rules. Domain objects represent business entity states and behaviors.
Database/infrastructure layer is the actual DBMS access layer, accessible through the business services layer or occasionally the user services layer.

Various Layers in the Architecture

Presentation layer handles all user interface and browser communication. It's exposed to the end user. Application layers can facilitate easier implementation swapping during testing.
Tests against layers like data or UI can use fake implementations for simpler, faster execution compared to real infrastructure.
Application logic layer executes specific business rules for requests. It creates separation between presentation and domain layers to improve design clarity. It also orchestrates use cases.
Application classes determine needed data from the accessor layer, process it, and deliver results to the presentation layer.
The Domain layer hosts entire business logic, with a model and related services. Models are often Entity-Relationship Models. Entities expose both data and behavior.
Domain services encapsulate related behaviors that operate on multiple entities. They often rely on the infrastructure layer for actions like read/write operations.
The goal of models is to use a ubiquitous language to describe and express business actions.

Implementing the Layered Architecture

Layers (Presentation, Application Logic, Domain, Database) are defined to facilitate separation of concerns and encapsulation.
Presentation layer includes GUI and Boundary classes handling user interactions and commands.
Application logic comprises control classes coordinating application activity; it doesn't hold business logic but can hold application task progress.
Domain layer includes entity classes containing information about the business domain, use cases, and rules. Domain objects encapsulate the state and behavior of business entities.
The Database layer contains the LocalDB with entities--an already established database.

ActiveX Data Objects (ADO)

ADO is a set of classes providing data access services to .NET programmers.
ADO provides a programming interface for database access.
It enables consistent access to data sources like SQL Server, OLE DB, and XML.
ADO.NET facilitates data sharing, retrieval, manipulation, and updating in distributed applications.
It is part of the .NET framework providing access to relational data, XML, and application data. It supports various development needs, including front-end database clients, middle-tier business objects, and various tools, languages, and internet browsers.

ADO.NET Components

Data providers (e.g. Connection) are component sets.
Dataset objects can be populated from diverse sources and are disconnected from their original source. A DataSet houses DataTable objects.
DataAdapter retrieves data from sources to populate tables in a DataSet, reconciles DataSet changes to the source, and utilizes Connection and Command objects from the .NET framework.

Namespaces

Namespaces are containers that organize classes in C# programs to prevent naming conflicts.
System.Data.SqlClient is the namespace for SQL Server data access. It houses provider-specific ADO.NET classes for connecting to and interacting with SQL Server databases. It manages interactions, including setting up connections with SQLConnection, inserting data using SqlCommand, and handling rows using SqlDataReader objects.
SqlCommand is the core class in System.SqlClient for executing CRUD (Create, Read, Update, Delete) operations on databases.
Namespaces such as System.Data provide access to classes supporting ADO.NET architecture for efficient data management from multiple sources. The Sqlconnection class represents an open connection, while SqlDataAdapter and SqlCommand augment performance.

Database and Structured Query Language(SQL)

Relational databases consist of tables with rows and columns. Tables store specific, structured data.
SQL, a database communication language, enables defining, querying, and controlling data.
Data Definition Language (DDL) defines and modifies database schema. DDL commands include CREATE, DROP (delete/remove), and ALTER (modify) for database objects like tables, indexes, functions, views, and procedures.
Data Manipulation Language (DML) manipulates data. DML commands include INSERT, UPDATE, and DELETE.
LocalDB is an embedded SQL Server instance, suitable for small applications, minimizing setup complexity.

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Description

This quiz explores the key components of layered architecture, including the presentation, application logic, domain, and database layers. Understand how each layer interacts in a software system and their specific responsibilities. Perfect for students learning about software design principles.