Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
Which statement best defines a database view?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view is a virtual or logical table whose contents are defined by a query.
• Its result can contain selected rows, selected columns, derived values or data obtained from more than one source table.
• A standard view should not be confused with a physical copy of the underlying table data.
• Its result can contain selected rows, selected columns, derived values or data obtained from more than one source table.
• A standard view should not be confused with a physical copy of the underlying table data.
వివరణ:
Question 2
ప్రశ్న 2
An EMPLOYEE table contains Employee_ID, Name, Department and Salary. Ordinary users must see Employee_ID, Name and Department but must not see Salary. Which database feature is most suitable?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view can expose only selected columns from an underlying table.
• Access through such a view can provide users with required information without directly exposing excluded columns.
• This is an important security and customized-presentation use of database views.
• Access through such a view can provide users with required information without directly exposing excluded columns.
• This is an important security and customized-presentation use of database views.
వివరణ:
Question 3
ప్రశ్న 3
The tables from which a database view derives its data are commonly called:
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Tables referenced by the query defining a view are commonly called base tables.
• The view derives its rows and columns from these underlying sources.
• A view may also be defined using other views in addition to base tables.
• The view derives its rows and columns from these underlying sources.
• A view may also be defined using other views in addition to base tables.
వివరణ:
Question 4
ప్రశ్న 4
Which statement most accurately distinguishes an ordinary table from a standard non-materialized view?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A base table stores database data as part of its own database object.
• A standard non-materialized view represents the result of a stored query rather than maintaining an independent duplicate set of ordinary rows.
• Both tables and views can present rows and columns and can normally be queried.
• A standard non-materialized view represents the result of a stored query rather than maintaining an independent duplicate set of ordinary rows.
• Both tables and views can present rows and columns and can normally be queried.
వివరణ:
Question 5
ప్రశ్న 5
Which statement about the sources used to define a database view is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view-defining query can obtain data from one or more tables.
• Views can also be based on other views in common relational database systems.
• Therefore a view is not restricted to showing every column of exactly one table.
• Views can also be based on other views in common relational database systems.
• Therefore a view is not restricted to showing every column of exactly one table.
వివరణ:
Question 6
ప్రశ్న 6
For a standard non-materialized view, which statement about storage is most accurate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A standard non-materialized view stores its defining query rather than an independent copy of all result rows.
• When the view is referenced, the DBMS derives the relevant result from the underlying data.
• Materialized or specially indexed views are distinct concepts and should not be confused with an ordinary view.
• When the view is referenced, the DBMS derives the relevant result from the underlying data.
• Materialized or specially indexed views are distinct concepts and should not be confused with an ordinary view.
వివరణ:
Question 7
ప్రశ్న 7
A view displays employees whose Status is 'Active'. An employee's Status in the underlying table is changed from 'Active' to 'Inactive'. What should normally happen when the standard view is queried again?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A standard view derives its result from its underlying data and defining query.
• If an underlying row changes so that it no longer satisfies the view condition, it will normally disappear from the view result when queried again.
• The view does not independently preserve the obsolete value.
• If an underlying row changes so that it no longer satisfies the view condition, it will normally disappear from the view result when queried again.
• The view does not independently preserve the obsolete value.
వివరణ:
Question 8
ప్రశ్న 8
An administrator repeatedly uses a complex join between EMPLOYEE and DEPARTMENT to display Employee_Name together with Department_Name. What is a useful role of a view in this situation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Views can hide the complexity of joins and other query logic behind a simpler database object.
• Users can query the view without repeatedly writing the complete underlying join expression.
• The source tables continue to exist and supply the data.
• Users can query the view without repeatedly writing the complete underlying join expression.
• The source tables continue to exist and supply the data.
వివరణ:
Question 9
ప్రశ్న 9
An EMPLOYEE table contains 20 rows. Exactly 8 rows have Status = 'Active'. A view is defined to return only rows where Status = 'Active', with no join, aggregation or additional condition. How many rows should the view return at that moment?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The view condition selects only rows whose Status value is 'Active'.
• The question states that exactly 8 of the 20 rows satisfy this condition.
• Therefore the view result contains 8 rows at that moment.
• The question states that exactly 8 of the 20 rows satisfy this condition.
• Therefore the view result contains 8 rows at that moment.
వివరణ:
Question 10
ప్రశ్న 10
Which statement about modifying data through a database view is NOT generally correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Some views can be updatable, but updatability is subject to rules and restrictions.
• Complex views involving aggregates, grouping, derived expressions or multiple underlying sources can restrict modification operations.
• Therefore it is incorrect to claim that every view is always fully modifiable.
• Complex views involving aggregates, grouping, derived expressions or multiple underlying sources can restrict modification operations.
• Therefore it is incorrect to claim that every view is always fully modifiable.
వివరణ:
Question 11
ప్రశ్న 11
In a basic CREATE VIEW definition, which component primarily determines which expressions or source columns appear as columns in the resulting view?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view is defined by a query, and the selected expressions form the data presented as view columns.
• The view may expose only a subset of source-table columns or may include derived expressions.
• Physical disk sectors and operating-system user counts do not define the logical columns of a database view.
• The view may expose only a subset of source-table columns or may include derived expressions.
• Physical disk sectors and operating-system user counts do not define the logical columns of a database view.
వివరణ:
Question 12
ప్రశ్న 12
A database contains a large PERSONNEL table, but a supervisor needs to work only with records belonging to the supervisor's own division. Which purpose of a view is most directly illustrated by creating a division-specific view?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view can filter source-table rows according to a defined condition.
• This lets different users work with focused representations relevant to their duties.
• Such customization is a common reason for using views.
• This lets different users work with focused representations relevant to their duties.
• Such customization is a common reason for using views.
వివరణ:
Question 13
ప్రశ్న 13
A SALES table contains Quantity and Unit_Price. A view is defined to display Order_ID and the expression Quantity * Unit_Price as Amount. Which statement is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view-defining query can contain expressions that derive values from source columns.
• Quantity × Unit_Price can therefore be presented as a calculated Amount column in the view.
• This logical presentation does not by itself add a new stored column to the SALES base table.
• Quantity × Unit_Price can therefore be presented as a calculated Amount column in the view.
• This logical presentation does not by itself add a new stored column to the SALES base table.
వివరణ:
Question 14
ప్రశ్న 14
What normally happens when an ordinary view is dropped while its underlying base table is retained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Dropping a view removes the view database object and its definition.
• The underlying base table is a separate database object and is not deleted merely because the view is dropped.
• This is an important distinction between removing a view and dropping a base table.
• The underlying base table is a separate database object and is not deleted merely because the view is dropped.
• This is an important distinction between removing a view and dropping a base table.
వివరణ:
Question 15
ప్రశ్న 15
Why is an ordinary database view commonly described as a 'virtual table'?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view presents named rows and columns and can normally be queried in a table-like manner.
• However, a standard non-materialized view derives those results from its defining query and source data.
• This table-like logical presentation is why the term virtual table is commonly used.
• However, a standard non-materialized view derives those results from its defining query and source data.
• This table-like logical presentation is why the term virtual table is commonly used.
వివరణ:
Question 16
ప్రశ్న 16
A base table contains a column named Emp_Full_Name, but users should see it through a view as Employee_Name. Which view capability makes this possible without renaming the original base-table column?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view can expose columns using names or aliases chosen for the view's presentation.
• This provides a different logical interface without necessarily altering the underlying table definition.
• Views can therefore help customize how database structures are presented to users.
• This provides a different logical interface without necessarily altering the underlying table definition.
• Views can therefore help customize how database structures are presented to users.
వివరణ:
Question 17
ప్రశ్న 17
Consider the following statements about ordinary database views:
1. A view can present selected rows or columns from underlying data.
2. A view may be defined using data from more than one table.
3. Every ordinary view necessarily stores a complete separate physical copy of its result rows.
4. Views can simplify the way users interact with complex queries.
Which statements are correct?
1. A view can present selected rows or columns from underlying data.
2. A view may be defined using data from more than one table.
3. Every ordinary view necessarily stores a complete separate physical copy of its result rows.
4. Views can simplify the way users interact with complex queries.
Which statements are correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Statements 1 and 2 are correct because views can filter or combine underlying data.
• Statement 4 is correct because a complex defining query can be hidden behind a simpler view interface.
• Statement 3 is false for an ordinary non-materialized view, which does not necessarily store a separate physical copy of its result set.
• Statement 4 is correct because a complex defining query can be hidden behind a simpler view interface.
• Statement 3 is false for an ordinary non-materialized view, which does not necessarily store a separate physical copy of its result set.
వివరణ:
Question 18
ప్రశ్న 18
Assertion (A): A database view must always expose every column of every underlying table.
Reason (R): A view-defining query can select only particular columns required for the intended presentation.
Choose the correct answer.
Reason (R): A view-defining query can select only particular columns required for the intended presentation.
Choose the correct answer.
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The Assertion is false because a view can expose only a selected subset of source-table columns.
• The Reason is true because the defining query determines which required columns are presented.
• Selective column exposure is one of the ways views support customization and controlled access.
• The Reason is true because the defining query determines which required columns are presented.
• Selective column exposure is one of the ways views support customization and controlled access.
వివరణ:
Question 19
ప్రశ్న 19
Match List I with List II:
List I
(a) View
(b) Base table
(c) View definition
(d) Virtual table
List II
1. Table-like logical result presented by a stored query
2. Query specification that determines the view's contents
3. Underlying table from which a view can derive data
4. Database object commonly used to present selected or derived data
Choose the correct matching code.
List I
(a) View
(b) Base table
(c) View definition
(d) Virtual table
List II
1. Table-like logical result presented by a stored query
2. Query specification that determines the view's contents
3. Underlying table from which a view can derive data
4. Database object commonly used to present selected or derived data
Choose the correct matching code.
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view presents selected or derived database data, giving (a)-4.
• A base table supplies underlying data, while the view definition is the query specification, giving (b)-3 and (c)-2.
• Virtual table describes the table-like logical result of the view, giving (d)-1.
• A base table supplies underlying data, while the view definition is the query specification, giving (b)-3 and (c)-2.
• Virtual table describes the table-like logical result of the view, giving (d)-1.
వివరణ:
Question 20
ప్రశ్న 20
A PERSONNEL table contains Employee_ID, Name, Department, Salary and Bank_Account. A clerk requires Employee_ID, Name and Department for routine work but must not be given direct access to Salary or Bank_Account. Which design is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A view can expose only those columns required for a user's work.
• Appropriate permissions can allow access through the view without requiring direct access to sensitive columns in the base table.
• This combines customized presentation with a useful database-access-control mechanism.
• Appropriate permissions can allow access through the view without requiring direct access to sensitive columns in the base table.
• This combines customized presentation with a useful database-access-control mechanism.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: C. A virtual table whose rows and columns are defined by a query సమాధానం: C.
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Question 2 ప్రశ్న 2Answer: A. Create a view containing only the permitted columns and grant the users appropriate access to that view. సమాధానం: A.
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Question 3 ప్రశ్న 3Answer: D. Base tables సమాధానం: D.
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Question 4 ప్రశ్న 4Answer: B. A table stores its own data, whereas a standard non-materialized view primarily stores a query definition and derives its result from underlying data. సమాధానం: B.
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Question 5 ప్రశ్న 5Answer: D. A view can be defined from one table, multiple tables or, where supported, other views. సమాధానం: D.
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Question 6 ప్రశ్న 6Answer: C. Its definition is stored, while its ordinary row result is derived from underlying data when the view is referenced. సమాధానం: C.
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Question 7 ప్రశ్న 7Answer: A. That employee should no longer appear if the employee no longer satisfies the view's defining condition. సమాధానం: A.
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Question 8 ప్రశ్న 8Answer: B. To store the complex query as a reusable logical presentation that users can query more simply సమాధానం: B.
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Question 9 ప్రశ్న 9Answer: C. 8 సమాధానం: C.
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Question 10 ప్రశ్న 10Answer: D. Every view is always fully insertable, updatable and deletable regardless of its definition. సమాధానం: D.
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Question 11 ప్రశ్న 11Answer: B. The SELECT list of the view-defining query సమాధానం: B.
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Question 12 ప్రశ్న 12Answer: A. Providing a focused and customized presentation of selected underlying rows సమాధానం: A.
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Question 13 ప్రశ్న 13Answer: D. A view can present a derived column calculated by its defining query without necessarily adding that column to the base table. సమాధానం: D.
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Question 14 ప్రశ్న 14Answer: C. The view definition is removed, while the underlying table and its data remain. సమాధానం: C.
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Question 15 ప్రశ్న 15Answer: B. Because its query result can be treated in many ways like a table even though the standard view does not maintain an independent ordinary copy of the underlying row data సమాధానం: B.
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Question 16 ప్రశ్న 16Answer: A. A view can present a source column under an appropriate alias or view-column name. సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: B. 1, 2 and 4 only సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: D. Assertion is false, but Reason is true. సమాధానం: D.
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Question 19 ప్రశ్న 19Answer: A. (a)-4, (b)-3, (c)-2, (d)-1 సమాధానం: A.
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Question 20 ప్రశ్న 20Answer: C. Create a view exposing only Employee_ID, Name and Department and grant the clerk appropriate access to that view. సమాధానం: C.