Why Storing Phone Numbers as VARCHAR Beats BIGINT in Billion‑Row Databases

This article explains why phone numbers should be stored as VARCHAR(15~20) rather than INT/BIGINT, covering underlying principles, performance tests, internationalization, security, large‑scale optimization techniques, and a concrete best‑practice checklist for enterprise systems.

Database designMySQL indexingVARCHAR vs BIGINT

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Why Storing Phone Numbers as VARCHAR Beats BIGINT in Billion‑Row Databases

IT Services Circle

Apr 28, 2025 · Databases

Choosing the Right Data Type for Storing Billions of Phone Numbers: INT vs VARCHAR

This article examines why storing 2 billion phone numbers using INT or BIGINT is problematic and argues for using VARCHAR(20) to preserve data integrity, support international formats, simplify queries, and avoid common pitfalls in database design and development.

VARCHAR vs BIGINTdata integritydatabase schema

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Choosing the Right Data Type for Storing Billions of Phone Numbers: INT vs VARCHAR