In relational database architectures, a View is a virtual table whose contents are defined by an underlying query. Under standard SQL definitions, a physical SQL table is classified as which of the following view types?
💻 sql Snippet
CREATE VIEW Class_View AS
SELECT ClassID, CourseCode, Venue
FROM Class
WHERE Venue = 'A Block';
A.A virtual view, because it does not contain physical data of its own and depends on index files.
B.A base relation (or base table), which serves as the physical storage source upon which virtual views are constructed.
C.A materialized view, because its query results are cached on the disk and automatically recalculated using active triggers.
D.A dynamic view, because its schema definitions can be changed using DML commands during user transactions.
Which of the following is NOT a feature of Indexed sequential files?
A.Records are stored in sequence and index is maintained.
B.Dense and nondense types of indexes are maintained.
C.Track overflows and file overflow areas can not be ensured.
D.Cylinder index increases the efficiency
Write down the properties, access advantages, and limitations of a Sequential File (Sequence File Organization).
Write the properties of Sequence File.
Which of the following is INCORRECT with respect to the physical file structure of Indexed Sequential Files?
A.New records are added to an overflow file.
B.The record in the main file that precedes a new record is updated to contain a pointer to the new record.
C.The overflow data is merged with the main file during a batch update.
D.Multiple indexes for the same key field cannot be setup.
Which of the following is NOT a feature or characteristic of the Indexed Sequential file organization?
A.Records are physically stored in sequence and an index structure is maintained.
B.Dense and non-dense types of indexes are supported and maintained.
C.Track overflows and file overflow areas cannot be ensured or managed by the storage engine.
D.We choose a specific number of storage buckets to correspond to the number of search key values we will have stored.
In database modeling, views are categorized into different types. Consider a view created using the SQL statement:
```sql
CREATE VIEW ActiveStudents AS
SELECT StudentID, StudentName, CGPA
FROM STUDENT
WHERE Status = 'Active';
```
What is the name of the physical table this view is based on, what type of view is this, and what are the main differences between Simple views, Complex views, and Materialized views?
💻 sql Snippet
CREATE VIEW ActiveStudents AS
SELECT StudentID, StudentName, CGPA
FROM STUDENT
WHERE Status = 'Active';
A.Base Table: STUDENT. View Type: Simple View. Differences:
- Simple view: Queries a single base table, contains no aggregate functions, and is updateable.
- Complex view: Spans multiple tables (uses joins), contains aggregates, and is generally read-only.
- Materialized view: Physically caches query results on disk and must be periodically refreshed.
B.Base Table: ActiveStudents. View Type: Materialized View. Differences: Simple views are cached on disk, complex views are temporary sessions, and materialized views exist as pure metadata.
C.Base Table: StudentName. View Type: Complex View. Differences: Simple views are stored in the DRAM cache, complex views use SRAM, and materialized views require optical disks.
D.Base Table: Status. View Type: Dynamic View. Differences: Simple views are created using DML, complex views use DDL, and materialized views can never be updated.
Write down the properties, access advantages, and major limitations of Sequential File Organization.
Write down three physical factors or parameters that must be specified when defining a search key while designing an indexed sequential file structure.
Under physical file organization standards, write down three key properties and access characteristics of a Sequential File (or sequence file organization).
💻 text Snippet
-- Sequential File Representation on disk blocks:
-- [Record 1: Key 101] -> [Record 2: Key 102] -> [Record 3: Key 103]
