Choosing the right data format in your database can lead to improved efficiency, data consistency, and performance. By storing measurements in their smallest unit, standardizing time data, and avoiding floats for currency, you can keep your database clean and optimized. Whether you’re designing a small app or a large-scale system, following these best practices will help ensure smooth and accurate data handling for years to come.

1. Storing Height and Other Measurements

When storing measurements such as height, weight, or distance, picking a consistent unit for all records is essential. Using a smaller unit can help avoid decimal precision issues and allow for easier calculations.

Recommendation: Store height in centimeters or millimeters.

• Example: Instead of storing height as 5.6 feet or 1.7 meters, store it as 170 centimeters.
• Why: This ensures uniformity, reduces conversion complexity, and eliminates the need for decimals, which can sometimes lead to rounding errors.

2. Storing Time Data

Time-related data (like duration or elapsed time) is best stored in a standardized format that can support multiple levels of granularity, from seconds to hours.

Recommendation: Store time in seconds or minutes.

• Example: Rather than saving 2.5 hours, store it as 150 minutes.
• Why: Storing in smaller units like seconds or minutes enables easier conversions for reporting and calculations, especially if you need to sum up different time periods. Many date and time libraries can easily convert seconds into any desired format.

Additional Tip: Use TIMESTAMP or DATETIME data types for specific dates and times, as they are optimized for date and time storage and calculations within most databases.

3. Storing Currency

For financial data, accuracy is critical, so choosing the right data type and unit is essential. Avoid using floating-point data types due to their rounding issues.

Recommendation: Store currency in cents (or the smallest currency unit) using an integer data type.

• Example: Instead of saving $99.99, store it as 9999 cents.
• Why: Using an integer to represent the smallest unit prevents rounding errors and maintains accuracy in financial calculations.

4. Storing Boolean Data

Boolean values (true/false) are common in applications but can sometimes be over-complicated in storage.

Recommendation: Use a BIT or TINYINT type.

• Example: Store true as 1 and false as 0.
• Why: These data types are optimized for Boolean storage, saving space and ensuring consistency across your application.

5. Storing Text-Based Data (e.g., Descriptions)

When storing text, the choice between VARCHAR, TEXT, and other text types depends on the length and usage of the data.

Recommendation:

• Use VARCHAR for short, fixed-length strings.
• Use TEXT or MEDIUMTEXT for longer descriptions or notes.

Why: VARCHAR is optimal for shorter text fields as it allows for indexing and uses less storage space, while TEXT types are more appropriate for larger amounts of unstructured data.

6. Storing Enum-like Data (e.g., Status or Category)

Enum-like fields, such as “status” or “category,” can benefit from numeric storage types or database ENUM types.

Recommendation: Store as ENUM or small integers (TINYINT).

• Example: Define an ENUM for status values like "active", "inactive," and "pending," or store as integers (e.g., 1 for active, 2 for inactive).
• Why: This approach reduces storage space, enables fast indexing, and keeps queries efficient.