Test
Data Management- Conceptual Models
Este test tiene tipos de pregunta que se abren en el reproductor de siempre.
Preguntas del test (85)
1An attribute or combination of attributes strictly used for data retrieval purposes.
- ACandidate Key
- BSuperkey
- CSecondary Key
- DForeign Key
2An attribute or combination of attributes that uniquely identifies each row in a table.
- ACampaign Key
- BSuperkey
- CKey
- DSecondary Key
3A column or set of columns in a table that uniquely identifies any database row without referring to any other data.
- ASuperkey
- BPrimary Key
- CCandidate Key
- DSecondary Key
4A field or set of fields in one table that uniquely identifies a tuple of another table.
- AForeign Key
- BSuperkey
- CCandidate Key
- DSecondary Key
5In which of the following operations can referential integrity problems occur?
- ASELECT
- BUPDATE
- CINSERT
- DDELETE
6To be considered minimally relational, which of the following key relational operators must a DBMS support?
- ASELECT
- BPRODUCT
- CJOIN
- DPROJECT
- EUNION
7A [blank_start]relvar[blank_end] is a container for holding relation data, not the relation itself.
- Arelvar
8In relational algebra, [blank_start]SELECT[blank_end] is a relational operator used to select a subset of rows.
- ASELECT
9In relational algebra, SELECT is also known as RESTRICT.
- AVerdadero
- BFalso
10In relational algebra, SELECT is a [blank_start]unary[blank_end] operator.
- Aunary
- Bbinary
11In relational algebra, an operator used to select a subset of columns.
- ASELECT
- BPROJECT
- CINTERSECT
- DPRODUCT
12In relational algebra, [blank_start]SELECT[blank_end] yields a horizontal subset of a table.
- ASELECT
- BPROJECT
13In relational algebra, [blank_start]PROJECT[blank_end] yields a vertical subset of a table.
- ASELECT
- BPROJECT
14[blank_start]UNION[blank_end] combines all rows from two tables; excluding duplicate rows.
- AUNION
15Which two conditions must be true for tables to be used in a UNION?
- AMust have the same number of columns.
- BMust have the same column names.
- CTheir corresponding columns must share the same or compatible domains.
- DThe entire rows must be exact duplicates.
16When two or more tables have the same number of columns and the corresponding columns have compatible domains, they are said to be union-compatible.
- AVerdadero
- BFalso
17In relational algebra, [blank_start]INTERSECT[blank_end] yields only the rows that appear in both tables.
- AUNION
- BINTERSECT
- CJOIN
18In relational algebra, [blank_start]DIFFERENCE[blank_end] yields rows that are in one table but are not in another.
- ADIFFERENCE
- BPROJECT
- CUNION ALL
19What is a Cartesian product?
- AThe result of multiplying the table row count by a factor of 10.
- BAll possible pairs of rows from two tables.
- CThe set of records returned by the right side of an outer join.
20In relational algebra, [blank_start]PRODUCT[blank_end] is an operator used to yield all possible pairs of rows from two tables.
- APRODUCT
21In relational algebra, a [blank_start]JOIN[blank_end] is a type of operator used to yield rows from two tables based on criteria.
- AJOIN
22A [blank_start]natural join[blank_end] links tables by selecting only rows with common values in their common attributes.
- Anatural join
- Bouter join
- Cinner join
23[blank_start]Equijoin[blank_end] is a join operator that links tables based on an equality condition that compares specified columns of the tables.
- AEquijoin
24[blank_start]Theta-join[blank_end] is a join operator that links tables using an inequality comparison operator (<, >, <=, >=) in the join condition.
- ATheta-join
25In relational algebra, an operator that answers queries about one set of data being associated with all values of data in another set of data.
- APRODUCT
- BDIVIDE
- CBASE
- DJOIN
26The [blank_start]Relational Select Operation[blank_end] retrieves one or more rows of a table, depending on whether the search argument is a unique or non-unique attribute.
- ARelational Select Operation
- BJoin Operation
- CRelational Project Operation
27The [blank_start]Join operation[blank_end] integrates data from two or more tables or combines them and is implemented in the FROM and WHERE clauses.
- ARelational Select Operation
- BJoin Operation
- CRelational Project Operation
28The [blank_start]Relational Project Operation[blank_end] retrieves all rows and some attributes of a table without using a WHERE clause to limit which rows of the table are included.
- ARelational Project Operation
- BJoin Operation
- CRelational Select Operation
29[blank_start]Information resource dictionary[blank_end] is an alternative name for the data dictionary.
- AInformation resource dictionary
30The system catalog can be described as a detailed system data dictionary that describes all objects within the database.
- AVerdadero
- BFalso
31The system catalog contains information about authorized users and access privileges.
- AVerdadero
- BFalso
32To lessen confusion, you should incorporate database homonyms into the design.
- AVerdadero
- BFalso
33A database [blank_start]synonym[blank_end] (not the object) involves the use of different names to identify the same object, such as an entity, an attribute, or a relationship.
- Asynonym
34Database synonyms should be avoided when ever possible.
- AVerdadero
- BFalso
35Which type of relationship is the relational modeling ideal and should be the norm in any relational database design?
- AOne-to-one (1:1)
- BOne-to-many (1:M)
- CMany-to-many (M:N or M:M)
36The 1:1 relationship should be rare in a relational database design.
- AVerdadero
- BFalso
37What is the degree of a relationship?
- AThe number of conditions required for the relationship.
- BThe number of entity types that participate in the relationship.
- CThe number of joins required to select all data elements.
38A [blank_start]binary[blank_end] relationship is when two entities participate, and is the most common relationship degree.
- Abinary
39A [blank_start]unary[blank_end] relationship is when both participants in the relationship are the same entity.
- Aunary
40A [blank_start]ternary[blank_end] relationship is when three entities participate in the relationship.
- Aternary
41What are the three most common relationships in ER models?
- ABinary
- BTertiary
- CSecondary
- DUnary
- ETernary
42The one-to-many (1:M) relationship is easily implemented in the relational model by putting the primary key of the "1" side in the table of the "many" side as a foreign key.
- AVerdadero
- BFalso
43Any candidate key must have the not-null and unique constraints enforced.
- AVerdadero
- BFalso
44A [blank_start]composite[blank_end] entity is an entity designed to transform an M:N relationship into two 1:M relationships.
- Acomposite
- Bresolution
- Cdistinct
45A composite entity is also called a bridge entity or associative entity.
- AVerdadero
- BFalso
46A composite entity is used to
- Aconvert 1:M relationships into 1:1 relationships
- Bchange M:N relationships into 1:1 relationships
- Ctransform an M:N relationship into two 1:M relationships
- Dpreserver M:M relationships
47A linking table is the implementation of a composite entity.
- AVerdadero
- BFalso
48[blank_start]Cardinality[blank_end] denotes how many instances of one object are related to instances of another object.
- ACardinality
49[blank_start]Modality[blank_end] denotes an instance of a specific entity is optional or mandatory in a relationship.
- AModality
50Modality refers to the maximum number of times an instance of an entity can be associated with an instance in a related entity while cardinality refers to the minimum number of times this relationship can occur.
- AVerdadero
- BFalso
51What type of unary relationship is depicted in the image?
- AOne-to-many Relationship
- BMany-to-many Relationship
- COne-to-one Relationship
52What type of relationship is depicted in the image?
- AMany-to-many Relationship
- BOne-to-many Relationship
- COne-to-one Relationship
53What type of relationship is depicted in the image?
- AMany-to-many Relationship
- BOne-to-one Relationship
- COne-to-many Relationship
54The proper use of foreign keys minimizes data redundancies and the chances that destructive data anomalies will develop.
- AVerdadero
- BFalso
55The real test of redundancy is not how many copies of a given attribute are stored, but whether the elimination of an attribute will eliminate information.
- AVerdadero
- BFalso
56[blank_start]Controlled[blank_end] redundancies are often designed as part of the system to ensure transaction speed and/or information requirements.
- AControlled
- BChaotic
57Certain levels of data redundancy may be required for a system to operate properly.
- AVerdadero
- BFalso
58An [blank_start]index key[blank_end] is, in effect, the index's reference point.
- Aindex key
- Bindex pointer
- Cindex number
59A [blank_start]unique index[blank_end] is an index in which the index key can have only one associated pointer value (row).
- Aunique index
60[blank_start]Entity integrity[blank_end] describes a condition in which all tuples within a table are uniquely identified by their primary key.
- AEntity integrity
61[blank_start]Referential integrity[blank_end] describes a condition in which a foreign key value has a match in the corresponding table or in which the foreign key value is null.
- AReferential integrity
62Which relational algebra operators can be applied to a pair of tables that are not union-compatible?
- APRODUCT
- BINTERSECT
- CJOIN
- DDISSECT
- EDIVIDE
63In DB2, [blank_start]area[blank_end] is a named section of permanent storage that is reserved to store the database.
- Aarea
64What is a property of relational operators that permits the use of relational algebra operators on existing tables (relations) to produce new relations
- Aarea
- Bclosure
- Cperimeter
65[blank_start]Determination[blank_end] is the role of a key. In the context of a database table, the statement "A determines B" indicates that knowing the value of A means that the value of B can be looked up.
- ADetermination
66An [blank_start]identifying[blank_end] relationship means that the child table cannot be uniquely identified without the parent.
- Aidentifying
67A [blank_start]non-identifying[blank_end] relationship is one where the child can be identified independently of the parent.
- Anon-identifying
- Bidentifying
- Cindependent
68The idea of determination is unique to the database environment.
- AVerdadero
- BFalso
69[blank_start]JOIN[blank_end] is the real power behind the relational database, allowing the use of independent tables linked by common attributes.
- AJOIN
70A(n) [blank_start]equijoin[blank_end] links tables on the basis of an equality condition that compares specified columns of each table.
- Aequijoin
71[blank_start]PRODUCT[blank_end] yields all possible pairs of rows from two tables, also known as the Cartesian product.
- APRODUCT
72[blank_start]M:N[blank_end] relationships can be implemented by creating a new entity in 1:M relationships with the original entities.
- AM:N
- B1:1
- C1:N
73The DIVIDE operation uses one single column table (e.g., column "a") as the divisor and one two column table (e.g., columns "a" and "b") as the dividend.
- AVerdadero
- BFalso
74The proper use of [blank_start]foreign[blank_end] keys is crucial to controlling data redundancy.
- Aforeign
75A primary key is a(n) [blank_start]candidate[blank_end] key selected to uniquely identify all other attribute values in a given row.
- Acandidate
76Primary keys are required in relational databases to ensure entity integrity.
- AVerdadero
- BFalso
77________ returns only the attributes requested, in the order in which they are requested.
- ASELECT
- BUNION
- CDIFFERENCE
- DPROJECT
78RDBMSs enforce integrity rules automatically.
- AVerdadero
- BFalso
79The word [blank_start]relation[blank_end], also known as a dataset in Microsoft Access, is based on the mathematical set theory from which Codd derived his model.
- Arelation
80One characteristic of generalization hierarchies is that they are implemented as [blank_start]1:1[blank_end] relationships.
- A1:1
- B1:M
- CM:N
81Proper data [blank_start]warehousing[blank_end] design requires carefully defined and controlled data redundancies to function properly.
- Awarehousing
- Bmodel
82Date attributes contain calendar dates stored in a special format known as the _____ date format.
- AEpoch
- Bcalendar
- CJulian
- Dlogical
83_____ logic, used extensively in mathematics, provides a framework in which an assertion (statement of fact) can be verified as either true or false.
- ARelational
- BPredicate
- CDatabase
- DIndex
84Only a single attribute, not multiple attributes, can define functional dependence.
- AVerdadero
- BFalso
85Dr. Codd's [blank_start]Guaranteed access rule (second rule)[blank_end] of relational database states that every value in a table is guaranteed to be accessible through a combination of table name, primary key value, and column name.
- AGuaranteed access rule (second rule)
Información
- Descripción
- Information Technology Test sobre Data Management- Conceptual Models, creado por Jason Shanks el 02/03/2021.
- Autor
- Jason Shanks
- Idioma
- English
- Visitas
- 0
- Etiquetas
- Valoración
- Aún sin valoraciones Valora este test