Q&A Hero

Q: Explain normalization and its different forms.

Q: According to the Data-Modeling Checklist, ____________________ should be nouns that are familiar to business and should be short and meaningful, and should document abbreviations, synonyms, and aliases for each entity.

Q: The combination of ____________________ and ER modeling yields a useful ERD, whose entities may now be translated into appropriate table structures.

Q: The ____________________ provides the big picture, or macro view, of an organization's data requirements and operations.

Q: In ____________________, no row may contain two or more multivalued facts about an entity.

Q: When a nonkey attribute is the determinant of a key attribute the table is in 3NF but not ____________________.

Q: It becomes difficult to create a suitable ____________________ key when the related table uses a composite primary key.

Q: In a real-world environment, changing granularity requirements might dictate changes in primary key selection, and those changes might ultimately require the use of ____________________ keys.

Q: ____________________ refers to the level of detail represented by the values stored in a table's row.

Q: An attribute that cannot be further divided is said to display ____________________.

Q: Any attribute whose value determines other values within a row is called a(n) ____________________.

Q: Because a partial dependency can exist only if a table's primary key is composed of several attributes, a table whose ____________________ key consists of only a single attribute is automatically in 2NF if it is in 1NF.

Q: Data redundancies occur from ____________________ of data on every row entry.

Q: All relational tables satisfy the ____________________ requirements.

Q: A diagram that depicts all dependencies found within a given table structure is known as a(n) ____________________.

Q: The problem with transitive dependencies is that they still yield data ____________________.

Q: Dependencies can be identified with the help of a dependency ____________________.

Q: A dependency based on only a part of a composite primary key is called a(n) ____________________.

Q: Any attribute that is at least part of a key is known as a(n) ____________________.

Q: A relational table must not contain ____________________ groups.

Q: ____________________ is a process to help reduce the likelihood of data anomalies.

Q: A(n) ____________________ derives its name from the fact that a group of multiple entries of the same type can exist for any single key attribute occurrence.

Q: In order to meet ____________________ requirements, you may have to denormalize some portion of the database.

Q: The price paid for increased performance through denormalization is a larger amount of ____________________.

Q: Normalization works through a series of stages called ____________________ forms.

Q: If database tables are treated as though they were files in a file system, the ____________________ never has a chance to demonstrate its superior data-handling capabilities.

Q: ____ databases reflect the ever-growing demand for greater scope and depth in the data on which decision support systems increasingly rely.a. Normalized b. Data warehouse c. Temporaryd. Report

Q: The conflicts between design efficiency, information requirements, and processing speed are often resolved through ____. a. conversion from 1NF to 2NF b. conversion from 2NF to 3NF c. compromises that include denormalization d. conversion from 3NF to 4NF

Q: An example of denormalization is using a ____ denormalized table to hold report data. This is required when creating a tabular report in which the columns represent data that is stored in the table as rows.a. transitive b. 3NF c. componentd. temporary

Q: Normalization represents a micro view of the ____ within the ERD.a. entities b. attributes c. relationshipsd. forms

Q: When designing a database, you should ____. a. make sure entities are in normal form before table structures are created b. create table structures then normalize the database c. only normalize the database when performance problems occur d. consider more important issues such as performance before normalizing

Q: A table is in 4NF if it is in 3NF and ____. a. all attributes must be dependent on the primary key, and must be dependent on each other b. all attributes are unrelated c. has no multivalued dependencies d. no column contains the same values

Q: A table where all attributes are dependent on the primary key and are independent of each other, and no row contains two or more multivalued facts about an entity, is said to be in ____.a. 1NF b. 2NF c. 3NFd. 4NF

Q: Most designers consider the BCNF as a special case of the ____.a. 1NF b. 2NF c. 3NFd. 4NF

Q: BCNF can be violated only if the table contains more than one ____ key.a. primary b. candidate c. foreignd. secondary

Q: A table where every determinant is a candidate key is said to be in ____.a. BCNF b. 2NF c. 3NFd. 4NF

Q: To generate a surrogate key, Microsoft Access uses a(n) ____ data type.a. surrogate b. sequence c. AutoNumberd. identity

Q: For most business transactional databases, we should normalize relations into ____.a. 1NF b. 2NF c. 3NFd. 6NF

Q: In a real-world environment, we must strike a balance between design integrity and ____.a. robustnessb. flexibility c. uniquenessd. ease of use

Q: In what two cases are composite primary keys particularly useful?

Q: Explain the "no change over time" characteristic of a good primary key.

Q: What is an entity cluster?

Q: Describe specialization and generalization.

Q: What do specialization hierarchies do?

Q: The main concern with redundant relationships is that they remain ____________________ across the model.

Q: The most common design trap is known as a(n) ____________________.

Q: From a data modeling point of view, ____________________ data refer to data whose values change over time and for which you must keep a history of the data changes.

Q: If you use a surrogate key, you must ensure that the candidate key of the entity in question performs properly through the use of the "____________________" and "not null" constraints.

Q: Composite keys are useful as identifiers of weak entities, where the weak entity has a strong ____________________ relationship with the parent entity.

Q: Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed ____________________ in the M:N relationship.

Q: Usually, a data modeler uses a natural identifier as the ____________________ of the entity being modeled, assuming that the entity has a natural identifier.

Q: An entity cluster is considered "virtual" or "____________________" in the sense that it is not actually an entity in the final ERD.

Q: Specialization is based on grouping ____________________ characteristics and relationships of the subtypes.

Q: ____________________ completeness means that every supertype occurrence must be a member of at least one subtype.

Q: ____________________ completeness means that not every supertype occurrence is a member of a subtype.

Q: The ____________________ constraint specifies whether each entity supertype occurrence must also be a member of at least one subtype.

Q: Subtypes that contain nonunique subsets of the supertype entity set are known as ____________________ subtypes.

Q: Disjoint subtypes are also known as ____________________ subtypes.

Q: The ____________________ is the result of adding more semantic constructs to the original entity relationship (ER) model.

Q: ____ relationships occur when there are multiple relationship paths between related entities.a. Redundant b. Duplicated c. Time-variantd. Supertype

Q: A ____ occurs when you have one entity in two 1:M relationships to other entities, thus producing an association among the other entities that is not expressed in the model.a. surrogate primary keys b. time-variant data c. design trapd. fan trap

Q: ____ data refer to data whose values change over time and for which you must keep a history of the data changes.a. Time-sensitive b. Time-variant c. Historicald. Change-based

Q: When selecting a foreign key placement for a 1:1 relationship, place the PK of the entity on the mandatory side in the entity on the optional side as a FK, and make the FK mandatory when ____. a. one side is mandatory and the other side is optional b. one side participates in another relationship c. both sides are optional d. both sides are mandatory

Q: The preferred placement for a foreign key when working with a 1:1 relationship is to ____. a. use the same primary key for both entities b. create a bridge entity c. place a foreign key in one of the entities d. place a foreign key in both entities

Q: ____ keys work with primary keys to properly implement relationships in the relational model.a. Foreign b. Composite c. Naturald. Surrogate

Q: Surrogate primary keys are especially helpful when there is no ____ key.a. primary b. natural c. foreignd. composite

Q: The "____" characteristic of a primary key states the following:The PK should not have embedded semantic meaning. An attribute with embedded semantic meaning is probably better used as a descriptive characteristic of the entity rather than as an identifier.a. unique values b. nonintelligent c. preferably single-attributed. security compliant

Q: The "____" characteristic of a primary key states the following:The selected primary key must not be composed of any attribute(s) that might be considered a security risk or violation. For example, using a Social Security number as a PK in an EMPLOYEE table is not a good idea.a. unique values b. nonintelligent c. preferably single-attributed. security-compliant

Q: The "____" characteristic of a primary key states the following:The PK must uniquely identify each entity instance. A primary key must be able to guarantee unique values. It cannot contain nulls.a. unique values b. nonintelligent c. preferably single-attributed. security complaint

Q: Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed only once in the ____ relationship.a. 0:1 b. 1:1 c. 1:Md. M:N

Q: The primary key's main function is to uniquely identify a(n) ____ within a table.a. attribute b. entity instance or row c. entity subtyped. natural identifier

Q: If one exists, a data modeler uses a ____ as the primary key of the entity being modeled.a. foreign key b. combination key c. surrogate keyd. natural identifier

Q: A ____ key is a real-world, generally accepted identifier used to uniquely identify real-world objects.a. primary b. natural c. foreignd. surrogate

Q: The most important characteristic of an entity is its ____ key, used to uniquely identify each entity instance.a. primary b. natural c. foreignd. surrogate

Q: An entity cluster is formed by combining multiple interrelated entities into ____.a. a single abstract entity object b. multiple abstract entity objects c. a single entity objectd. multiple entity objects

Q: ____ is the bottom-up process of identifying a higher-level, more generic entity supertype from lower-level entity subtypes.a. Specialization b. Generalization c. Partial completenessd. Total completeness

Q: Partial completeness is symbolized by ____.a. a dotted line b. two dashed lines c. a circle over a single lined. a circle over a double line

Q: Overlapping subtypes are subtypes that contain ____ subsets of the supertype entity set.a. entity b. subtypes c. uniqued. nonunique

Q: Non-overlapping subtypes are subtypes that contain a(n) ____ subset of the supertype entity set.a. entity b. subtypes c. uniqued. nonunique

Q: The default comparison condition for the subtype discriminator attribute is the ____ comparison.a. not equality b. less than c. greater thand. equality