IT214 - Study
A function that has no partial functional dependencies is in which form:
2NF The table is in 2NF if it is in 1NF and no partial dependencies exist.
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:P
In a database, a foreign key is defined as:
A data element/attribute within a data field of a data record within a database table that is a primary key in another database table.
The term which expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity is known as___.
Cardinality
The___constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.
Completeness
A(n) ___ attribute is an attribute that can be divided in simpler parts that have a different semantic meaning in the real world.
Composite
An attribute that can be divided in simpler parts that have a different semantic meaning in the real world, is known as:
Composite attribute
Crow's foot notation depicts a weak relationship by placing a___line between the entities.
Dashed
A relationship___indicates the number of entities or participants associated with a relationship.
Degree
___subtypes are subtypes that contain a unique subset of the supertype entity set.
Disjoint
An attribute that may have two different values for two entity instances is named:
Duplicated value attribute
A student's "G number" in the university is not an example of required attribute.
FALSE, it is
A new entity, called the bridge entity, is created to represent a 1:1 relationship.
FALSE: A new entity, called the bridge entity, is created to represent the M:M relationship.
A ternary relationship is one in which a relationship can exist between occurrences of the same entity set.
FALSE: A recursive relationship is one in which a relationship can exist between occurrences of the same entity set.
A required attribute is an attribute that must have a value only for all entity instances already defined.
FALSE: A required attribute is an attribute that must have a value for all entity instances (already defined or to be defined in the future)
A subtype discriminator is an attribute in the subtype entity that determines to which supertype the subtype occurrence is related.
FALSE: A subtype discriminator is the attribute in the supertype entity that determines to which subtype the supertype occurrence is related.
A table is said to be in the Third Normal Form when, it is in the second normal form and it HAS transitive dependency.
FALSE: A table is said to be in the Third Normal Form when, it is in the Second Normal form and it doesn't have Transitive Dependency.
A binary relationship exists when an association is maintained within a single entity.
FALSE: A unary relationship exists when an association is maintained within a single entity.
For the entity PERSON the attribute SSN is not an example of a unique values attribute.
FALSE: A unique (value) attribute is an attribute that have a unique (different) value or no value at all for all entity instances (already defined or to be defined in the future). Each person has a different SSN or does not have a SSN at all, therefore SSN is a unique attribute
For the entity PERSON the attribute fullname is an example of a unique values attribute.
FALSE: A unique (value) attribute is an attribute that have a unique (different) value or no value at all for all entity instances (already defined or to be defined in the future). There are two persons that have the same full name, therefore fullname is not a unique attribute.
Attributes have a unique value for each entity instance.
FALSE: Attributes have a unique value for each entity instance.
Disjoint subtypes are subtypes that contain non-unique subsets of the supertype entity set.
FALSE: Disjoint subtypes are subtypes that contain a unique subset of the supertype entity set.
Entity (E1) is "Optional" if for any entity instance of Entity (E2) there must be a corresponding entity instance of Entity (E1) for the relationship R.
FALSE: Entity (E1) is "Mandatory" if for any entity instance of Entity (E2) there must be a corresponding entity instance of Entity (E1) for the relationship R.
Entity (E1) is "MANDATORY" if for any entity instance of Entity (E2), it may or may not exist an entity instance Entity (E1) for the relationship R.
FALSE: Entity (E1) is "OPTIONAL" if for any entity instance of Entity (E2), it may or may not exist an entity instance Entity (E1) for the relationship R.
For the entity CITY the attribute name is an example of a composite attribute.
FALSE: For the entity CITY the attribute name is an example of a simple attribute, because is a unstructured text and cannot be divided in subparts. By definition, a simple attribute is an attribute that cannot be divided in simpler parts that have a different semantic meaning in the real world.
For the entity PERSON the attribute address is an example of a simple attribute.
FALSE: For the entity PERSON the attribute address is an example of a composite attribute, because it may be divided in street, city, state, and zipcode that have a different semantic meaning. By definition, a composite attribute is an attribute that can be divided in simpler parts that have a different semantic meaning in the real world.
For the entity PERSON the attribute first_name is not an example of a required attribute.
FALSE: For the entity PERSON the attribute first_name is an example of a required attribute, because all persons must have a first name. By definition, a required attribute is an attribute that must have a value for all entity instances
The term "connectivity" expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.
FALSE: Its actually "CARDINALITY" that expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity
Overlapping subtypes are subtypes that contain unique subsets of the supertype entity set.
FALSE: Overlapping subtypes are subtypes that contain nonunique subsets of the supertype entity set.
Subtype entity is an entity type that has got relationship with one or more subtypes and it contains attributes that are common to its subtypes.
FALSE: Subtype entity are subgroups of the supertype entity and have unique attributes, but they will be different from each subtype
The entities that participate in a relationship are not known as participants.
FALSE: The entities that participate in a relationship are also known as participants.
The gender of a person is an example of a multi-value attribute.
FALSE: The gender of a person is an example of single-value attribute, because any person has a single gender.
Partial completeness means that every supertype occurrence must be a member of at least one subtype.
FALSE: Total completeness means that every supertype occurrence must be a member of at least one subtype.
First normal form (1NF) has one or more repeating groups, no primary key and multi value cells.
FALSE: Unnormalized form (UNF) has one or more repeating groups, no primary key and multi value cells
For the entity PERSON the attribute fullname is not an example of a duplicated values attribute.
FALSE: You are correct. A duplicated value attribute is an attribute that may have the same value for two entity instances (already defined or to be defined in the future). There are two persons that have the same full name, therefore fullname is a duplicated value attribute.
Unnormalized form (UNF) has non repeating groups and single value cells.
FALSE: Unnormalized form (UNF) has one or more repeating groups and multi value cells.
A "simple" primary key is composed of two or more attributes.
FALSE: A "simple" primary key is composed of a single attribute
The primary keys of supertype and subtype entities are not identical.
False: The primary keys of supertype and subtype entities are always identical.
For meeting database design requirements, which of the following is correct statement for "entities" ?
It Identify what type of data the database will store.
Which of the following types of attributes has two or more values for some entity instances?
Multi-valued attributes
A "biological" father (Entity 1) is father of several children and a child (Entity 2) has a single "biological" father (Entity 1). The relationship "is father" is an example of___relationship type.
One to many or 1:M
An attribute that may not have a value for some entity instances (already defined or to be defined in the future) is named:
Optional
For which attribute among the following, a conventional NULL value is used if an entity instance does not have a value for that attribute?
Optional attribute
The entities that participate in a relationship are also known as___.
Participants
For which attributes, all entity instances must have a value for it?
Required attributes
A___primary key is composed of a single attribute.
Simple Any of the keys described before (ie: primary, secondary or foreign) may have one or more attributes. A simple key consists of a single attribute to uniquely identify an entity occurrence, for example, a student number, which uniquely identifies a particular student. No two students would have the same student number.
An attribute that cannnot be divided in simpler parts that have a different semantic meaning in the real world, is known as:
Simple attribute
Entity supertypes and subtypes are organized in a ______ hierarchy, which depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).
Specialization
___relationship exists when the PK of the related entity contains a PK component of the parent entity.
Strong
A PILOT entity might be a(n) ________ of the EMPLOYEE entity.
Subtype
A___entity is an entity type that has got relationship with one or more subtypes and it contains attributes that are common to its subtypes.
Supertype
"Middle name" of a person is an example of optional attribute.
TRUE
A "required" attribute must have a value in it and cannot be left blank.
TRUE
A "simple" primary key is composed of a single attribute.
TRUE
A foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table or the same table.
TRUE
A multi-valued attribute has two or more values for some entity instances.
TRUE
A relationship degree indicates the number of entities or participants associated with a relationship.
TRUE
A single-value attribute has exactly a value for any given entity instance.
TRUE
A table is in 1NF if it has primary key, non repeating groups and the table cells must be of single value.
TRUE
A table is said to be in the Third Normal Form when, it is in the second normal form and it DOESN'T have transitive dependency.
TRUE
A unary relationship exists when an association is maintained within a single entity.
TRUE
A weak relationship is also known as non-identifying relationship.
TRUE
An optional attribute is an attribute that may not have a value for some entity instances
TRUE
Disjoint subtypes are subtypes that contain a unique subset of the supertype entity set.
TRUE
Entity (E1) is "Optional" if for any entity instance of Entity (E2), it may or may not exist an entity instance Entity (E1) for the relationship R.
TRUE
Entity supertypes and subtypes are organized in a specialization hierarchy, which depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).
TRUE
For meeting database design requirements, "constraints" identify what specific constraints and rules are applied to the data in the business process.
TRUE
In one-to-many relationship type, several entity instances may be in relation with one entity instance.
TRUE
One important inheritance characteristic is that all entity subtypes inherit their primary key attribute from their supertype.
TRUE
Relationship in ER model can be defined as an association among entities.
TRUE
Supertype entity is an entity type that has got relationship with one or more subtypes and it contains attributes that are common to its subtype
TRUE
Supertype entity is an entity type that has got relationship with one or more subtypes and it contains attributes that are not common to its subtypes.
TRUE
The completeness constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.
TRUE
The existence of an optional entity indicates that the minimum cardinality is 0 for the optional entity.
TRUE
The extended entity relationship model (EERM) is sometimes referred to as the enhanced entity relationship model.
TRUE
The table is in 2NF if it is in 1NF and no partial dependencies exist.
TRUE
Total completeness is symbolized by a circle over a double line.
TRUE
Weak relationship exists if the PK of the related entity does not contain a PK component of the parent entity.
TRUE
For the entity PERSON the attribute first_name is an example of a required attribute.
TRUE For the entity PERSON the attribute first_name is an example of a required attribute, because all persons must have a first name. By definition, a required attribute is an attribute that must have a value for all entity instances
For the entity PERSON the attribute middle_name is an example of an optional attribute.
TRUE: For the entity PERSON the attribute middle_name is an example of an optional attribute, because some persons may not have a middle name. By definition, an optional attribute is an attribute that may not have a value for some entity instances
A recursive relationship is one in which a relationship can exist between occurrences of the same entity set.
TRUE: A recursive relationship is one in which a relationship can exist between occurrences of the same entity set.
When a bridge entity is created to solve M:M relationships, two 1:M relationships between the bridge and the original entities are created.
TRUE: When a bridge entity is created to solve M:M relationships, two 1:M relationships between the original entities and the bridge entity are created
A___relationship exists when three entities are associated.
Ternary
Entity is a:
Thing in real world.
Specify for the following attributes if they are unique attributes (UQ) or duplicated attributes (DUP) by writing UQ or DUP in the table below: ATTRIBUTE VALUES. UQ/DUP name Atalanta,Atletico Barcelona [name] = picture. atalanta.png, atletico.png, barcelona.png. [picture] = country ita, esp, ger [country] =
UQ UQ DUP
___ normal form has one or more repeating groups, no primary key and multi value cells.
Unnormalized
Normalization ________ data duplication. What should be the correct answer among the following to fill the blank:
eliminates
The property of___enables an entity subtype to inherit the attributes and relationships of the supertype.
inheritance
Several children may have the same father is an example of___relationship type.
many to one/ M:1
Specify for the following attributes if they are simple (SA) or composite (CA) by writing SA or CA in the table below: ATTRIBUTESA/CA name[name] = description[description] = msrp[msrp] = mpg[mpg] = city mpg[citympg] = hwy mpg[hwympg] = photo file[photofile] =
name[name] = SA description[description] = SA msrp[msrp] = SA mpg[mpg] = CA city mpg[citympg] = SA hwy mpg[hwympg] = SA photo file[photofile] = CA
Specify for the following attributes if they are required attributes (REQ) or optional attributes (OPT) by writing REQ or OPT in the table below: ATTRIBUTE.....VALUES........REQ/OPT ---------------------------------------------------- power.....Hybrid, Plug-in Hybrid, ...[power] = note.....First-Ever[note] = year.....2020[year] = name......Corolla, Prius, ...[name] = style.....Hybrid, Hatchback, ...[style] = filename....corolla_ hybrid.png, ...[file] = starting_price.....23100, 20290, ...[start] = featured_price....23555, 24340, ...[feature] = MPG ct/hw........53/52, 30/38, ...[MPG] =
power.....Hybrid, Plug-in Hybrid, ...[power] = OPT note.....First-Ever[note] = OPT year.....2020[year] = REQ name......Corolla, Prius, ...[name] = REQ style.....Hybrid, Hatchback, ...[style] = OPT filename....corolla_ hybrid.png, ...[file] = REQ starting_price.....23100, 20290, ...[start] = REQ featured_price....23555, 24340, ...[feature] = REQ MPG ct/hw........53/52, 30/38, ...[MPG] = REQ
A PILOT entity might be a(n) ________ of the EMPLOYEE entity. Which one of the following options mentioned below is correct? characteristic subtype attribute supertype cluster
subtype
Specify for the following attributes if they are simple (SA) or composite (CA) by writing SA or CA in the table below: ATTRIBUTESA/CA time[time] = description[description] = temp[temp] = feels[feels] = precip[precip] = humidity[humidity] = wind[wind] =
time[time] = CA description[description] = CA temp[temp] = SA feels[feels] = SA precip[precip] = SA humidity[humidity] = SA wind[wind] = CA
Specify for the following attributes if they are single-value attributes (SVA) or multi-value attributes (MVA) by writing SVA or MVA in the table below: ATTRIBUTE !! SVA/MVA title[title] = authors[authors] = picture[picture] =
title[title] = SVA authors[authors] = MVA picture[picture] = SVA
A___relationship exists when an association is maintained within a single entity.
unary
An attribute that have a different value or no value at all for all entity instances already defined or to be defined in the future is named:
unique value
KEEP GOING, YOU CAN DO IT ;)
wampus
