1Z0-052 · Question #101
Which three statements are true about logical structures of the Oracle database? (Choose three.)
The correct answer is A. Each segment contains one or more extents. C. A data block is the smallest unit of input/output (I/O) in data files. D. It is possible to have tablespaces of different block sizes in a database. Oracle logical storage structures follow a strict hierarchy: tablespace contains segments, segments contain extents, and extents contain data blocks. Understanding block sizing and structure hierarchy is essential for Oracle DBA certification.
Question
Which three statements are true about logical structures of the Oracle database? (Choose three.)
Options
- AEach segment contains one or more extents.
- BMultiple tablespaces can share a single data file.
- CA data block is the smallest unit of input/output (I/O) in data files.
- DIt is possible to have tablespaces of different block sizes in a database.
- EEach data block in the database always corresponds to one operating system block.
How the community answered
(49 responses)- A92% (45)
- B6% (3)
- E2% (1)
Why each option
Oracle logical storage structures follow a strict hierarchy: tablespace contains segments, segments contain extents, and extents contain data blocks. Understanding block sizing and structure hierarchy is essential for Oracle DBA certification.
A segment is a logical storage unit allocated for a specific database object (table, index, etc.), and it is always composed of one or more contiguous extents allocated from the tablespace.
A data file belongs to exactly one tablespace; it is the reverse relationship that allows multiple data files to belong to a single tablespace, never sharing across tablespaces.
The Oracle data block is the finest granularity of I/O that Oracle performs against a data file; Oracle reads and writes data in units of blocks, not individual rows or OS blocks.
Oracle supports multiple block sizes within a single database using the BLOCKSIZE clause on CREATE TABLESPACE, allowing tablespaces of 2K, 4K, 8K, 16K, or 32K alongside the default DB_BLOCK_SIZE.
An Oracle data block can span one or more operating system blocks depending on the configured DB_BLOCK_SIZE relative to the OS block size, so a one-to-one correspondence is not guaranteed.
Concept tested: Oracle logical storage hierarchy and block sizing
Source: https://docs.oracle.com/en/database/oracle/oracle-database/19/cncpt/logical-storage-structures.html
Topics
Community Discussion
No community discussion yet for this question.