The data models defined by ANSI/SPARC architecture are
Answer: D
Correct answer: Logical, physical and view
The ANSI/SPARC three-schema architecture has an internal or physical schema, a conceptual or logical schema, and external or view schemas - one per user group. Separating them is what makes data independence possible.
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Which among the following field type can store maximum data?
Answer: D
Correct answer: Memo fields
A Memo field holds long text - up to 65,535 characters - against a Text field's 255. Date/Time and Yes/No fields hold a fixed few bytes each.
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In SQL, testing whether a subquery is empty is done using
Answer: D
Correct answer: EXISTS
EXISTS takes a subquery and yields true if it returns at least one row, so NOT EXISTS tests emptiness. DISTINCT and UNIQUE concern duplicates and NULL tests a single value.
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Which of the following is not a recovery technique?
Answer: C
Correct answer: Two-phase commit
Deferred update, immediate update and shadow paging are all recovery techniques. Two-phase commit is a protocol for making a distributed transaction commit consistently across several sites - a concurrency and coordination problem rather than recovery from failure.
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The ______ approach reduces the time and effort required for design and carries less risk in database management.
Answer: B
Correct answer: Multiple databases
Splitting the design into several smaller databases means each can be designed, tested and changed on its own, so less has to be got right at once and a mistake affects less. A single global database has to be designed as one piece, which is both slower and riskier.
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____ table store information about database or about the system.
Answer: B
Correct answer: System
System tables, also called the catalogue or data dictionary, hold the database's description of itself - the tables, columns, indexes, users and permissions that exist. They are how the DBMS knows what it is managing.
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Relationships among relationships can be represented in an-E-R model using
Answer: A
Correct answer: Aggregation
Aggregation treats a relationship as though it were an entity, so that a further relationship can be attached to it. Without it there is no way to relate one relationship to another.
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What will be the number of columns and rows respectively obtained for the operation, A- B, if A B are Base union compatible and all the rows of a are common to B? Assume A has 4 columns and 10 rows; and B has 4 columns and 15 rows
Answer: A
Correct answer: 4,0
The difference \( A - B \) keeps A's columns, so the degree is still 4. It returns the tuples of A that are not in B, and every row of A is said to appear in B, so no rows remain.
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The set of all values that can be taken by the attribute is called as _______ of the attribute.
Answer: D
Correct answer: Domain
The domain of an attribute is the set of values it may take - integers in a range, a list of permitted codes, dates. Cardinality is the number of tuples and degree the number of attributes.
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Which among the following filter method is not available in Access?
Answer: C
Correct answer: Advanced filter
Access offers Filter by Selection and Filter by Form as its two filtering commands. Its third facility is Advanced Filter/Sort, which opens a query-like grid and both filters and sorts - not a plain advanced filter alongside the other two.
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