Oracle data type choice for fixed-length text For an alphanumeric column with a fixed length in Oracle, the most appropriate data type is:

Introduction / Context:
Choosing between CHAR and VARCHAR2 in Oracle depends on whether the text length is fixed or variable. Fixed-length codes (e.g., country_code, status_code) benefit from CHAR for simpler semantics and potential storage/CPU advantages at small sizes.

Given Data / Assumptions:

• Values are alphanumeric and always the same length (e.g., exactly 2 or 3 characters).
• We are not storing large free-form text.
• We want predictable storage and comparison behavior.

Concept / Approach:

Use CHAR(n) for fixed-length fields; Oracle pads to length n for storage/comparison semantics. VARCHAR2(n) is best for variable-length fields. LONG is obsolete and discouraged; CLOB is for large character data; NUMBER is numeric storage only.

Step-by-Step Solution:

Verification / Alternative check:

Oracle documentation advises VARCHAR2 for variable-length character strings and CHAR for fixed-length semantics, with LONG retained only for backward compatibility.

Why Other Options Are Wrong:

• VARCHAR2: variable length, not fixed.
• LONG: deprecated; use CLOB/VARCHAR2 instead.
• NUMBER: numeric, not text.
• CLOB: overkill for short fixed-length codes.

Common Pitfalls:

• Using VARCHAR2 for fixed-length codes causes inconsistent padding/comparisons.
• Using LONG complicates tooling and indexing.

Final Answer:

CHAR.