DBMS
| 1. | Which one of the options given below refers to the degree (or arity) of a relation in relational database systems ? | [GATE-2023: 1M] | |
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Number of attributes of its relation schema
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Number of tuples stored in the relation.
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Number of entries in the relation.
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Number of distinct domains of its relation
schema.
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| 2. | A prime attribute of a relation scheme R is an attribute that appears | [GATE-2014: 1M] | |
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in all candidate keys of R.
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in some candidate key of R.
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in a foreign key of R.
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only in the primary key of R.
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| 3. | In an Entity-Relationship (ER) model, suppose R is a many-to-one relationship from entity set E1 to entity set E2. Assume that E1 and E2 participate totally in R and that the cardinality of E1 is greater than the cardinality of E2. Which one of the following is true about R? | [GATE-2018: 1M] | |
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Every entity in E1 is associated with exactly one entity in E2.
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Some entity in E1 is associated with more than one entity in E2.
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Every entity in E2 is associated with exactly one entity in E1.
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Every entity in E2 is associated with at most one entity in E1.
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| 4. | Given the basic ER and relational models, which of the following is INCORRECT? | [GATE-2012: 1M] | |
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An attribute of an entity can have more than one value.
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An attribute of an entity can be composite.
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In a row of a relational table, an attribute can have more than one value.
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In a row of a relational table, an attribute can have exactly one value or a NULL value.
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| 5. | An ER model of a database consists of entity types A and B. These are connected by a relationship R which does not have its own attribute. Under which one of the following conditions, can the relational table for R be merged with that of A? | [GATE-2017: 1M] | |
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Relationship R is one-to-many and the participation of A in R is total.
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Relationship R is one-to-many and the participation of A in R is partial.
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Relationship R is many-to-one and the participation of A in R is total.
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Relationship R is many-to-one and the participation of A in R is partial.
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