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Information LEC[FA2]
CCS0021
| Question | Answer |
|---|---|
| True or False. The disjoint rule in disjointness constraints is an instance of supertype can only one of the subtypes | True |
| True or False. The total specailization in completeness constraints is represented by a single line | False |
| True or False. An EERD stands for Explained Entity Relationship Diagram | False |
| True or False. The disjoint rule in disjointness constraints is where an instance of the supertype could be more than one of the subtypes. | False |
| What is a subgrouping of entities in an entitye type that has attributes distinct from those in other subgroupings | Subtype |
| If supertype A has three subtypes which are subtypes 1, 2 and 3, and subtypes 1 and 2 have a relationship, this means subtype 3 has also a relationship with subtypes 1 and 2. True or False. | False |
| What is the process of defining a more general entity type from a set of more specialized entity types. | Bottom-Up |
| In diagram 4, the attribute of Title of the House entity can be inherited by the Buildings entity. True or False. | False |
| In diagram 4, the attribute BldgNo of the Buildings entity will be inherited only by the Apartment entity. | False |
| True or False. The partial specialization rule is completeness constraints represented by a single line | True |
| True or False. When mapping regular entities to relation, the simple attributes of the entity are mapped directly onto the relation. | True |
| When Mapping a many to many binary relationship to a relation, we have to create a new relation with primary keys of the two entities as its primary key. True or False. | True |
| True or False. A relation in relational database is the same word relationship in an E-R model. | False |
| True or False. The order of the columns in the database table must be irrelevant. | True |
| True or False. Key fields can either be simple or composite keys. | True |
| True or False. Relations correspond with entity types. | True |
| True or False. Relations corresponds to an attribute of an entity type. | False |
| It is said to be that a table is in 1NF, if it is in 2nd normal form and every non-key attribute is fully functionally dependent of the entire primary key. Group of answer choices | False |
| True or False. A transitive dependency is when a non-key is functional dependent on another non-key | True |
| When there is an existing multivalued attribute in a 1NF | |
| A table that pertains more than one entity type is a well-structured relation. True or False | False |
| True or false. A completeness constraint identifies whether an instance of a supertype must also be a member of at least one subtype. | True |
| True or False. The total specialization rule in completeness constraints is represented by a double line | True |
| What is the process of defining a more general entity type from a set of more specialized entity types. | Generalization |
| True or False. The instances of a subtype must participate in a relationship unique to that subtype. | True |
| True or False. The overlap rule in disjointness constraints is where an instance of the supertype can be only one of the subtypes. | False |
| True or False. Relationships at the supertype level indicate that all subtypes will participate in the relationship | True |
| True or false. If supertype A has a relationship with supertype B, the subtypes under supertype A should not have a relationship with supertype B. | False |
| These is a set of one or more entity types and associated relationships grouped into a single abstract entity type. | Entity Cluster |
| True or False. Supertype entities inherit values of all attributes of the subtypes. | False |
| True or False. A primary key of a table guarantees that all rows are unique. | True |
| True or False. When mapping binary relationships of EER diagrams, if the relationship is one to many, a new relation with primary keys is made from two entities as its primary key. | False |
| What is a powerful SQL operation for retrieving and modifying data? | Data Manipulation |
| What is a named, two-dimensional table of data? | Relation |
| In mapping associative entities to relations and if no identifier is assigned, the default primary key for the association relation is composed of the primary keys of the two entities. | True |
| The columns of a database table is called a field. | True |
| True or False. A table is qualified to be a relation if it has the same name with other tables. | False |
| What is another name for tables in database? | relation |
| When can a table be qualified as a relation? | A table is qualified to be relation if it has a unique name. |
| True or False. Not all tables are relation. | True |
| True or False. A transitive dependency is when a non-key is functionally dependent on another non-key. | True |
| Anomalies found in relations are good because it helps build the relation. | False |
| True or False. An insertion anomaly is when adding a row in a table forces users to create duplicate data. | True |
| Which among the following is not true about table anomalies? | Modification anomaly forces the changes to not only one value to the data of the table but all similar data involved. |
| A well-structured relation contains minimal redundancy and allows users to insert, delete, and update rows without cause data inconsistencies. | True |
Created by:
AdoKwatro