| Term entity relationship (E-R) modelDefinition a logical representation of the data for an organization or for a business area, using entities for categories of data and relationships for associations between entitiesTerm entity-relationship (E-R) diagramDefinition a graphical representation of an entity relationship modelTerm Definition a statement that defines or constrains some aspect of the business. It is intended to assert business structure or to control or influence the behavior of the businessTerm Definition a word or phrase that has a specific meaning for the businessTerm Definition an association between two or more termsTerm Definition a person place or object or event or concept in the user environment about which the organization wishes to maintain dataTerm Definition a collection of entities that share common properties or characteristics (versus an entity instance); entity type is described just once with metadata in a databaseTerm Definition a single occurrence of an entity type; many instances of an entity type may be represented by data stored in the databaseTerm Definition a entity that exists independently of other entity typesTerm Definition an entity type whose existence depends on some other entity typeTerm Definition an entity type on which the weak entity type dependsTerm Definition the relationship between a weak entity type and its ownerTerm Definition a property or characteristic of an entity or relationship type that is of interest to the organizationTerm Definition an attribute that must have a value for every entity (or relationship) instance with which it is associatedTerm Definition a attribute that may not have a value for every entity (or relationship) instance with which it is associatedTerm Definition an attribute that has meaningful component parts (attributes)Term simple (or atomic) attributeDefinition an attribute that cannot be broken down into smaller components that are meaningful to the organizationTerm Definition an attribute that may take on more than one value for a given entity (or relationship) instance [e.g. skill]Term Definition an attribute whose values can be calculated from related attribute values; [e.g. GPA]; should be avoided if possible, as it may become outdatedTerm Definition an attribute (or combination of attributes) whose value distinguishes instances of an entity type (will brome primary key)Term Definition an identifier that consists of a composite attributeTerm Definition meaningful association between (or among) entity types; denoted by a line labeled with the name of the relationshipTerm Definition an association between (or among) entity instances where each relationship instance associates exactly one entity instance from each participating entity typeTerm Definition an entity type that associates the instances of one or more entity types and contains attributes that are peculiar to the relationship between those entity instancesTerm Definition the number of entity types that participate in a relationshipTerm Definition a relationship between instances of a single entity typeTerm Definition a relationship between the instances of two entity types; most commonTerm Definition a simultaneous relationship among the instances of three entity typesTerm Definition a rule that specifies the number of instances of one entity that can (or must) be associated with each instance of another entityTerm Definition minimum number of instances of one entity that may be associated with each instance of another entityTerm Definition maximum number of instances of one entity that may be associated with each instance of another entityTerm Definition a time value that is associated with a data value, often indicating when some event occurred that affected the data value Three conditions that suggest the designer should model a relationship as an associative entity type are Show
Languages menus and other facilities by which users interact with the database are collectively called an Which of the following is software used to create, maintain, and provide controlled access to databases? Database management system A centralized knowledge base of all data definitions, data relationships, screen and report formats, and other system components is called a A rule that can NOT be violated by database users is called a With the database approach, data descriptions are stored in a central location known as a A _______ is often developed by identifying a form or report that a user needs on a regular basis. A picture of the high-level entities for an organization and the relationships among the entities is called a A database is an organized collection of ______ related data Which of the following types of data can be stored in the database? Voice, letters, and numbers The database environment data processed in a way that increases a user's knowledge is Which of the following is an integrated decision support database with content derived from various operational databases? CASE is a class of tools that Automates the design of databases and application programs The common types of entities are: Strong, weak, and associative entities A relationship between the instances of a single entity type is called a ______ relationship. The number of entity types that participate in a relationship is called the What conditions should exist if an associative entity is to be created? 1) All the relationships for the participating entities are many-to-many. 2) The new associative entity has independent meaning. 3) The new associative entity participates in independent relationships. An entity that associates the instances of 1 or more in the entity types and contains attributes specific to the relationships is called a An attribute that uniquely identifies an entity, and consist of a composite attribute is called a The total quiz points for a student for an entire semester is a _____ attribute An attribute that can be calculated from related attribute values is called a _____ attribute And attribute that can be broken down into smaller parts is called a ______ attribute An attribute of an entity that must have a value for each entity instance is called a A property or characteristic of an entity type that is of interest to the organization is called a A person's name, birthday, and social security number are examples of An attribute that must have a value for every entity or relationship instance is called a A ______ is the relationship between a weak entity type and its owner An entity type who's existence depends on another entity type is called a _____ entity Customers, cars, and parts are examples of The logical representation of an organizations data is called a Entity-relationship model A _____ specifies the number of instances of one entity that can be associated with each instance of another entity A simultaneous relationship among the instances of three entity types is called a _____ relationship A relationship where the minimum and maximum cardinality are both one is a _____ relationship A student can attend 5 classes, each with a different professor. Each professor has 30 students. The relationship of the students to Professors is a _____ relationship A primary key who's value is unique across all relations is called a A functional dependency between 2 or more non key attributes is called a A functional dependency in which 1 or more non key attributes are functionally dependent on part, but not all, of the primary key is called a ____ dependency A relation that contains no multi valued attributes, and has no non key attributes solely dependent on the primary key, but contains transitive dependencies is it in which normal form? A constraint between 2 attributes is called a A relation that contains minimal redundancy and allows easy use is considered to be An attribute that uniquely identifies each row in a relation is called a A 2 dimensional table of data is called a The entity integrity rule states that No primary key attributes can be null An attribute in a relation of a database that serves as the primary key of another relation in the same database is called a Which relationship exists when three entities are associated?A ternary relationship is an association among three entities.
What type of a relationship is one that connects two instances of the same entity type with each other?A unary relationship, also called recursive, is one in which a relationship exists between occurrences of the same entity set. In this relationship, the primary and foreign keys are the same, but they represent two entities with different roles. See Figure 8.9 for an example.
What is a relationship between two entities?Representing the relationship between two entities
The relationship between two entities is shown with a diamond. The name of the relationship is specified inside the diamond. , for example, could be viewed as an entity type or a relationship between two people, depending on how the data was viewed.
Which type of relationship links instances of an entity set to other instances of same entity set example employee manages employee?A binary recursive relationship (e.g., “manages” in Figure 2.3) relates a particular Employee to another Employee by management. It is called recursive because the entity relates only to another instance of its own type.
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A simultaneous relationship among the instances of three entity types is called a relationship
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