What's the Difference Between Precision and Scale in Database Numeric Data Types?

Understanding Numerical Precision and Scale in Database Schemas

When defining numeric data columns in a database, you may encounter a notation such as "decimal(5,2)." This concept can be confusing, especially if you're unfamiliar with the underlying terminology. In this article, we'll delve into the meanings of precision and scale and how they affect the interpretation of numeric values.

Numeric Precision

Numeric precision refers to the maximum number of significant digits that can be stored in a number. In the example provided, "decimal(5,2)," the precision is 5. This means that the number can have up to five total digits, including both integer and decimal values.

Numeric Scale

Numeric scale refers to the number of decimal places that can be stored in a number. In our example, the scale is 2. This means that the number can have up to two decimal places.

Combining Precision and Scale

Combining precision and scale provides a clearer picture of the range of values that can be stored. In the case of "decimal(5,2)," the number can have a maximum value of 999.99 (four integer digits and two decimal digits).

Example

To illustrate this concept further, consider the value "123.45." This value has a precision of 5 (four integer digits and one decimal digit) and a scale of 2 (two decimal places). It falls within the acceptable range for "decimal(5,2)."

Conclusion

Understanding precision and scale is essential when defining numeric columns in databases. By specifying these values, you can ensure that your data is stored in a consistent and meaningful manner. If you have any further questions about this topic, please consult your database documentation or seek professional guidance.

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