- Developed by E. F. Codd of IBM in 1970, the relational model is based on mathematical set theory and represents data as independent relations - Each relation (table) is conceptually represented as a two-dimensional structure of intersecting rows and columns. The relations are related to each other through the sharing of common entity characteristics (values in columns).

Lesson 2 Flashcards by Brandon Rosales

Data modeling

The process of creating a specific data model for a determined problem domain

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Problem domain

A clearly defined area within the real-world environment, with a well-defined scope and boundaries that will be systematically addressed

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Data model

A representation, usually graphic, of a complex “real-world” data structure. Data models are used in the database design phase of the Database Life Cycle

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Entity

A person, place, thing, concept, or event for which data can be stored

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Attribute

A characteristic of an entity or object. An attribute has a name and a data type.

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One-to-many (1:M or 1…*) relationship

Associations among two or more entities that are used by data models. In a 1:M relationship, one entity instance is associated with many instances of the related entity.

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Many-to-many (M:N or …) relationship

Association among two or more entities in which one occurrence of an entity is associated with many occurrences of a related entity and one occurrence of the related entity is associated with many occurrences of the first entity.

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One-to-one (1:1 or 1…1) relationship

Associations among two or more entities that are used by data models. In a 1:1 relationship, one entity instance is associated with only one instance of the related entity.

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Constraint

A restriction placed on data, usually expressed in the form of rules

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Each record from first table is associated with many records in second table but each record in second table is associated with one record in first table.
What type of relationship is it?

One-to-many (1:M) relationship

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Single record in the first table is related to only one record in the second table and vice versa.
What type of relationship is it?

One-to-one (1:1) relationship

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Each record from first table is associated with many records in second table and one record in second table is associated with many records in first table
What type of relationship is it?

Many-to-many (M:M) relationship

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Business rule

A description of a policy, procedure, or principle within an organization. For example, a pilot cannot be on duty for more than 10 hours during a 24-hour period, or a professor may teach up to four classes during a semester.

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Hierarchical model

An early database model whose basic concepts and characteristics formed the basis for subsequent database development

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Segment

In the hierarchical data model, the equivalent of a file system’s record type

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Network model

An early data model that represented data as a collection of record types in 1:M relationships.

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Schema

A logical grouping of database objects, such as tables, indexes, views, and queries that are related to each other.

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Subschema

The portion of the database that interacts with application programs.

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Data manipulation language (DML)

The set of commands that allows an end user to manipulate the data in the database, such as SELECT, INSERT, UPDATE, DELETE, COMMIT, and ROLLBACK.

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Data definition language (DDL)

The language that allows a database administrator to define the database structure, schema, and subschema

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Relational database

a collection of relations that contain the data describing a particular business environment.

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Relational model

Developed by E. F. Codd of IBM in 1970, the relational model is based on mathematical set theory and represents data as independent relations
Each relation (table) is conceptually represented as a two-dimensional structure of intersecting rows and columns. The relations are related to each other through the sharing of common entity characteristics (values in columns).

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Relation

A logical construct perceived to be a two-dimensional structure composed of intersecting rows (entities) and columns (attributes) that represents an entity set in the relational model.

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Tables are somtimes called ______

Relation

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Tuple

In the relational model, a table row.

Relational database management system (RDBMS)

A collection of programs that manages a relational database. The RDBMS software translates a user's logical requests (queries) into commands that physically locate and retrieve the requested dat

Relational diagram

A graphical representation of a relational database's entities, the attributes within those entities, and the relationships among the entities.

Entity relationship (ER) Model

A data model that describes relationships (1:1, 1:M, and M:N) among entities at the conceptual level with the help of ER diagrams. The model was developed by Peter Chen.

Entity relationship diagram (ERD)

A diagram that depicts an entity relationship model's entities, attributes, and relations.

Entity instance (entity occurrence)

A row in a relational table

Entity set

A collection of like entities

Connectivity

The type of relationship between entities. Classifications include 1:1, 1:M, and M:N.

What are the 3 types of ER notations?

- Chen notation - Crow's foot notation - class diagram notation

Crow's Foot notation

A representation of the entity relationship diagram that uses a three-pronged symbol to represent the "many" sides of the relationship.

In relational database tables, a _____ describes a row and an ______ describes a column of that table.

Tuple; Attribute

OODM

- Object-oriented data model | - A data model whose basic modeling structure is an object

Object

An abstract representation of a realworld entity that has a unique identity, embedded properties, and the ability to interact with other objects and itself

Object-oriented database management system

- OODBMS | - Data management software used to manage data in an object-oriented database model.

Semantic data model

The first of a series of data models that more closely represented the real world, modeling both data and their relationships in a single structure known as an object.

Class

A collection of similar objects with shared structure (attributes) and behavior (methods). A class encapsulates an object's data representation and a method's implementation. Classes are organized in a class hierarchy.

Method

In the object-oriented data model, a named set of instructions to perform an action. Methods represent real-world actions, and are invoked through messages

Class hierarchy

The organization of classes in a hierarchical tree in which each parent class is a superclass and each child class is a subclass.

Inheritance

In the object-oriented data model, the ability of an object to inherit the data structure and methods of the classes above it in the class hierarchy.

UML

- Unified Model Language - A language based on object-oriented concepts that provides tools such as diagrams and symbols to graphically model a system.

Class diagram

A diagram used to represent data and their relationships in UML object notation.

_____ is a highly distributed, fault-tolerant file storage system designed to manage large amount of data at high speed.

HDFS (Hadoop Distributed File System)

ERDM

- Extended Relational Data Model - A model that includes the object-oriented model's best features in an inherently simpler relational database structural environment.

Object/Relational DBMS (O/R DBMS)

- A DBMS based on the extended relational model (ERDM). The ERDM, championed by many relational database researchers, constitutes the relational model's response to the OODM. - This model includes many of the object-oriented model's best features within an inherently simpler relational database structure.

Big Data

A movement to find new and better ways to manage large amounts of web-generated data and derive business insight from it, while simultaneously providing high performance and scalability at a reasonable cost.

What are the 3 V's in big data databases

- Volume - Velocity - Variety

Hadoop

A Java based, open source, high speed, fault-tolerant distributed storage and computational framework. It uses low-cost hardware to create clusters of thousands of computer nodes to store and process data.

HDFS

- Hadoop Distributed File System | - A highly distributed, fault-tolerant file storage system designed to manage large amounts of data at high speeds.

What are the three types of nodes that HDFS uses?

- Name node - Data node - Client mode

Name node

Stores all the metadata about the file system

Data node

The data node stores fixed-size data blocks

Client node

Acts as the interface between the user application and the HDFS

MapReduce

An open-source application programming interface (API) that provides fast data analytics services; one of the main Big Data technologies that allows organizations to process massive data stores

NoSQL

A new generation of database management systems that is not based on the traditional relational database model.

Key-value

A data model based on a structure composed of two data elements: a key and a value, in which every key has a corresponding value or set of values. Itl is also called the associative or attribute-value data model.

Sparse data

A case in which the number of table attributes is very large but the number of actual data instances is low.

Eventual consistency

A model for database consistency in which updates to the database will propagate through the system so that all data copies will be consistent eventually

In Chen notation, entities and relationships have to be oriented horizontally; not vertically. (T/F)

False

A(n) _______ is anything about which data are to be collected and stored.

entity

Even when a good database blueprint is available, an applications programmer's view of the data should match that of the manager and the end user. (T/F)

False

In the context of data models, an entity is a person, place, thing, or event about which data will be collected and stored. (T/F)

True

What is a disadvantage of the hierarchical data model?

It does not have standards.

In object oriented terms, a(n) _____ defines an object's behavior

Method

The object-oriented data model was developed in the _______ . (What is the year?)

1980s

A(n) _______ enables a database administrator to describe schema components.

Data definition langauge (DDL)

A data model is usually graphical (T/F)

True

Each row in a relation is called a ____

Tuple

Which of the following types of HDFS nodes stores all the metadata about a file system?

Name node

A _____ is a collection of similar objects with a shared structure and behavior.

Class

A _____ defines the environment in which data can be managed and is used to work with the data in the database.

data manipulation language,DML

The hierarchical data model was developed in the _______.

1960s-1970s

In a SQL-based relational database, each table is dependent on every other table. (T/F)

False

Business rules apply to businesses and government groups, but not to other types of organizations such as religious groups or research laboratories. (T/F)

False

From a database point of view, the collection of data becomes meaningful only when it reflects properly defined _______

Business rules

Today, most relational database products can be classified as object/relational. (T/F)

True

_______ are important because they help to ensure data integrity.

Constraints

Students and classes have a _______ relationship.

Many-to-many relationship

Database designers determine the data and information that yield the required understanding of the entire business. (T/F)

False

A _____ ____ is a brief, precise, and unambiguous description of a policy, procedure, or principle within a specific organization.

Business Rule

In _____ a three pronged symbol represents the "many" side of the relationship.

Crows foot notation

In the _______ model, each parent can have many children, but each child has only one parent.

Hierarchical

An implementation-ready data model should contain a description of the data structure that will store the end-user data. (T/F)

True

Business rules must be rendered in writing and be updated to reflect any change in the organization's operational environment. (T/F)

True

Each column in a relation represents a _____

Attribute

A verb associating two nouns in a business rule translates to a(n) _______ in the data model.

Relationship

A(n) _______ is bidirectional.

Relationship

The _______ model was developed to allow designers to use a graphical tool to examine structures rather than describing them with text.

Entity Relationship

A(n) _______ is a restriction placed on the data.

Constraint

Each row in the relational table is known as an entity instance or entity occurrence in the ER model. (T/F)

True

A ______ is a relatively simple representation of more complex real-world data structures.

Data Model

A(n) _______ represents a particular type of object in the real world.

Entity

Oracle 12c is an example of the _______.

XML/Hybrid data model

The relational data model was developed in the _______.

1970s

Within the database environment, a data model represents data structures with the purpose of supporting a specific problem domain. (T/F)

True

A _____ in a hierarchical model is the equivalent of a record in a file system

Segment

The relational model is hardware-dependent and software-independent. (T/F)

False

he relational model's foundation is a mathematical concept known as a _____

Relation

A ______ is the conceptual organization of an entire database as viewed by a database administrator

Schema

The _______ data model is said to be a semantic data model.

Object-oriented

The network model has structural level dependence. (T/F)

True

Each row in the relational table is known as a(n) ______

Entity instance

In the _______ model, the user perceives the database as a collection of records in 1:M relationships, where each record can have more than one parent.

Network

A noun in a business rule translates to a(n) _______ in the data model.

Entity

Which of the following types of HDFS nodes acts as the interface between the user application and the HDFS?

Client node

The _______ data model uses the concept of inheritance.

Object-oriented

In an SQL-based relational database, rows in different tables are related based on common values in common attributes. (T/F)

True

The hierarchical model is software-independent. (T/F)

False

What is true about NoSQL databases?

- not based on the relational model and SQL - support distributed database architectures. - provide high scalability, high availability, and fault tolerance. - support very large amounts of sparse data. - are geared toward performance rather than transaction consistency.

M:N relationships are not appropriate in a relational model. (T/F)

True

In the _______ model, the basic logical structure is represented as an upside-down tree.

Hierarchical

An implementation-ready data model needn't necessarily contain enforceable rules to guarantee the integrity of the data. (T/F)

False

The _______ model uses the term connectivity to label the relationship types.

entity relationship

A(n) _______ is the equivalent of a field in a file system

attribute

MySQL is an example of the _______.

Relational data model

A(n) ______'s main function is to help one understand the complexities of the real world environment.

Model

VMS/VSAM is an example of the _______.

File system data model

What is true about business rules?

They can serve as a communication tool between the users and designers.

A disadvantage of the relational database management system (RDBMS) is its inability to hide the complexities of the relational model from the user. (T/F)

False

NoSQL databases provide ______ tolerance

Fault

_______ are normally expressed in the form of rules.

Constraints