GAQM CITM-001 Practice Test - Questions Answers, Page 5

Classes are a fundamental concept in object-oriented programming and modeling. A class describes a group of objects that share the same features, constraints, semantics, and behavior. A class is shown as a rectangle with the class name and optionally with compartments for attributes and operations. Classes can be used to model real-world entities or system components.Classes can also have relationships with other classes, such as generalization, association, aggregation, or composition.Reference:1

Classes are a fundamental concept in object-oriented programming and modeling. A class describes a group of objects that share the same features, constraints, semantics, and behavior. A class is shown as a rectangle with the class name and optionally with compartments for attributes and operations. Classes can be used to model real-world entities or system components.Classes can also have relationships with other classes, such as generalization, association, aggregation, or composition.Reference: https://www.cs.toronto.edu/~sme/CSC340F/slides/11-objects.pdf

https://www.cs.toronto.edu/~jm/340S/Slides2/ClassD.pdf

A data flow diagram (DFD) is a graphical representation of data flow in any system.It uses defined symbols like rectangles, circles and arrows, plus short text labels, to show data inputs, outputs, storage points and the routes between each destination1. Data flow: data flows indicate the data movement between external entities, processes, and the data store.They're represented as arrows in the DFD with a short text label2.Therefore, the symbol that represents flow of data in DFD is arrow.Reference:1: What is a Data Flow Diagram | Lucidchart2: What Are Data Flow Diagrams? | Baeldung on Computer Science

A byte is the smallest unit of data storage that consists of eight bits. A bit is a binary digit that can have two values: 0 or 1. A byte can store one character, such as a letter, a number, or a symbol. An octet is another name for a byte, but it is not commonly used. A character is a symbol that represents a letter, a digit, or a punctuation mark, but it is not a unit of data storage. A field is a group of bytes that stores a specific type of data, such as a name, a date, or a number, but it is not the smallest unit of data storage.Reference:Data Storage Units of Measurement Table,What are the units of measurements for data storage?,Data Storage Units

A field is a unit of data that can store one or more characters, such as a name, a date, or a number. Fields are used to organize and store data in databases, spreadsheets, and other applications. A byte is a unit of digital information that consists of eight bits, which are binary digits that can have two values: 0 or 1. An octet is another term for a byte, especially in the context of network protocols and data transmission. A decimal is a number system that uses ten symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Decimals can also have a decimal point to represent fractions, such as 3.14 or 0.25.Reference:Certified IT Manager (CITM) Course Outline,Grouping Symbols and Order of Operations,A group of characters is called as a

An attribute is a property that describes various characteristics of an entity. For example, an entity type called Employee may have attributes such as name, age, salary, department, etc. An attribute can also be a primary key that uniquely identifies an entity instance, or a foreign key that references another entity type. An attribute can have a data type, a domain, and a constraint that define its format, range, and validity. An attribute is represented by an oval in an ER diagram, and by a column in a table.Reference:3,EXIN EPI Certified Information Technology Manager - EXIN(page 23)

The conceptual level is a high-level description of the data and its relationships in the database, without specifying how the data is physically stored or implemented. It defines the main entities, attributes, and constraints for the entire database, and is independent of any specific database management system or application. The conceptual level is also known as the logical level, and it is usually represented by an entity-relationship diagram (ERD).Reference:Conceptual schema - Wikipedia,Navigating the Three Levels of Database Design: Conceptual, Logical, and Physical

A relation is a type of association that describes how two or more entities are related to each other. A relation can have different properties, such as cardinality, optionality, and directionality, that specify the nature and constraints of the association. A relation can also have attributes that store information about the association. For example, a relation between Employee and Project entities can have an attribute called Role that indicates the role of each employee in each project. A relation can be represented by a line connecting the entities in an entity-relationship diagram (ERD).Reference:Association and Associative entity - IBM,When to use Associative entities? - Stack Overflow, [Entity-Relationship Model - Tutorialspoint].

A primary key is a column or combination of columns that contain values that uniquely identify each row in the table. It enforces the entity integrity of the table and prevents the insertion of duplicate rows. A table can have only one primary key, which is usually defined on an identity column or a column with not null and unique constraints.A primary key also creates a unique index for the table, which allows fast access to data when the primary key is used in queries12.Reference:1: Primary and Foreign Key Constraints - SQL Server12: Primary and Foreign Key in SQL With Examples - DataFlair2

A foreign key is a column or a set of columns in one table that references the primary key of another table. It is used to create a link and relationship between tables in a relational database.A foreign key ensures that the values in the referencing table match the values in the referenced table, thus maintaining the referential integrity of the database12.A foreign key can also be used to implement constraints such as cascading updates or deletes3.Reference:1: CITM Study Guide, Chapter 3: Database Management Systems, Page 41.2:Types of Keys in Relational Model (Candidate, Super, Primary, Alternate and Foreign)3:Database Keys: The Complete Guide (Surrogate, Natural, Composite & More)