SQL administration (storage management): which SQL command is used to allocate an extent for an existing table (for example, to grow its on-disk storage)?

Difficulty: Easy

Correct Answer: ALTER TABLE

Explanation:


Introduction / Context:
Some SQL dialects, especially those influenced by Oracle-style storage management, expose commands to influence physical storage, such as allocating additional extents to a segment. Although modern systems often auto-extend, administrators may still manually allocate space for performance or maintenance reasons.


Given Data / Assumptions:

  • We are dealing with an already existing table.
  • The task is “allocate an extent,” i.e., reserve additional contiguous storage for the table segment.
  • We seek the correct DDL verb used by mainstream SQL systems that support this feature.


Concept / Approach:
The command to change attributes or storage for an existing table is ALTER TABLE. In engines that support manual extent control, administrators issue statements like “ALTER TABLE table_name ALLOCATE EXTENT” with optional storage parameters. Pseudo-commands such as “MODIFY ALLOCATES,” “MODIFY TABLE,” or “REDEFINE TABLE” are not standard SQL DDL forms.


Step-by-Step Solution:

Identify action domain: change to an existing table’s storage.Map to the canonical DDL verb: ALTER TABLE.Select “ALTER TABLE” as the correct option.


Verification / Alternative check:
Storage clauses and extent management appear in vendor documentation with the ALTER TABLE command family, not with nonstandard verbs like “MODIFY TABLE.”


Why Other Options Are Wrong:

MODIFY ALLOCATES / MODIFY TABLE / REDEFINE TABLE: not standard SQL keywords for this operation.None of the above: incorrect because ALTER TABLE is valid and widely recognized.


Common Pitfalls:
Confusing logical schema DDL (columns, constraints) with physical storage options; or assuming every RDBMS exposes extent-level control—many manage extents automatically.


Final Answer:
ALTER TABLE

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