Lesson 2 Flashcards
Data modeling
The process of creating a specific data model for a determined problem domain
Problem domain
A clearly defined area within the real-world environment, with a well-defined scope and boundaries that will be systematically addressed
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
Entity
A person, place, thing, concept, or event for which data can be stored
Attribute
A characteristic of an entity or object. An attribute has a name and a data type.
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.
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.
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.
Constraint
A restriction placed on data, usually expressed in the form of rules
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
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
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
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.
Hierarchical model
An early database model whose basic concepts and characteristics formed the basis for subsequent database development
Segment
In the hierarchical data model, the equivalent of a file system’s record type
Network model
An early data model that represented data as a collection of record types in 1:M relationships.
Schema
A logical grouping of database objects, such as tables, indexes, views, and queries that are related to each other.
Subschema
The portion of the database that interacts with application programs.
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.
Data definition language (DDL)
The language that allows a database administrator to define the database structure, schema, and subschema
Relational database
a collection of relations that contain the data describing a particular business environment.
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).
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.
Tables are somtimes called ______
Relation
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
