NUMBER Data Type FAQS

 1. What is the Oracle NUMBER data type used for?

The NUMBER data type in Oracle is used to store numeric data, both integers and floating-point numbers, with customizable precision and scale. It is commonly used for storing financial data, quantities, and measurements that require numerical operations.

2. What is precision and scale in NUMBER data type?

• Precision refers to the total number of digits a number can have, both to the left and right of the decimal point.
• Scale refers to the number of digits to the right of the decimal point. If no scale is provided, it is assumed to be 0, meaning the number is an integer.

Example:

• NUMBER(5, 2) means the number can have up to 5 digits, with 2 digits after the decimal point (e.g., 999.99).
• NUMBER(7, 0) means the number can have up to 7 digits, with no decimal places (e.g., 9999999).

3. What happens if I insert a number that exceeds the defined precision or scale?

If you try to insert a number that exceeds the precision or scale defined for a column, Oracle will throw an error, indicating that the value is out of range. For example, inserting 1234.567 into a NUMBER(5, 2) column would result in an error because it exceeds the allowed precision.

4. What is the default precision and scale for the NUMBER data type?

When no precision and scale are specified, the default for the NUMBER data type is:

• Precision: 38 (maximum number of digits)
• Scale: 0 (meaning whole numbers only, i.e., integers)

5. What is the maximum precision and scale allowed for the NUMBER data type?

• Maximum precision: 38 digits.
• Maximum scale: The scale can be between 0 and the precision. For example, if the precision is 5, the scale can range from 0 to 5.

6. Can I store very large numbers with the NUMBER data type?

Yes, the NUMBER data type can store very large and very small numbers, both positive and negative, depending on the precision you specify. It is ideal for storing high-precision numerical data like financial or scientific measurements.

7. How much storage does a NUMBER column require?

The storage size for a NUMBER column is variable and depends on the precision. Typically, the storage size ranges from 1 to 22 bytes. Larger numbers with higher precision will require more storage.

8. Can NUMBER handle floating-point numbers?

Yes, the NUMBER data type can store floating-point numbers by specifying a scale greater than 0. For example, NUMBER(7, 2) can store floating-point numbers with up to 7 digits, 2 of which are after the decimal point.

9. What is the difference between NUMBER and FLOAT?

Both NUMBER and FLOAT can store floating-point numbers, but:

• FLOAT is typically used for very high precision floating-point numbers (usually defaulting to NUMBER(126)).
• NUMBER allows more flexibility in specifying both precision and scale.

10. What happens if I insert a value with a scale greater than the defined scale?

Oracle will round the value to the nearest value that fits the defined scale. For example, inserting 12.345 into a NUMBER(5, 2) column will round it to 12.35.

11. Can I use NUMBER for storing dates or strings?

No, the NUMBER data type is only for storing numeric values. To store dates, use the DATE or TIMESTAMP data type. For strings, use VARCHAR2 or CHAR.

12. Can I perform arithmetic operations on NUMBER columns?

Yes, you can perform arithmetic operations (addition, subtraction, multiplication, division, etc.) on columns with the NUMBER data type. Oracle will handle the precision and scale automatically during operations.

13. How do I handle rounding in the NUMBER data type?

When performing arithmetic operations on NUMBER columns, Oracle automatically rounds results based on the column's scale. You can also use the ROUND() function to manually round numbers to a specified number of decimal places.

14. Can I define a NUMBER column without specifying precision or scale?

Yes, if you omit both precision and scale, Oracle will assume the default values of NUMBER(38, 0) (up to 38 digits, no decimal places). However, it's recommended to specify the precision and scale for better control over your data.

15. Is the NUMBER data type compatible with other numeric types?

Yes, the NUMBER data type can be used interchangeably with other numeric types in most cases. However, other types like BINARY_FLOAT or BINARY_DOUBLE may be more suitable for specific use cases that require floating-point precision and performance optimizations.

16. What is the advantage of using NUMBER over INTEGER or FLOAT?

• Flexibility: The NUMBER data type allows you to define both precision and scale, providing flexibility in storing a wide range of numeric data.
• Customizable: You can customize precision and scale to fit your exact data requirements.
• Wide Range: It can handle both integers and floating-point numbers with a very wide range of values.

17. Can I use NUMBER for storing currency or financial data?

Yes, NUMBER is ideal for storing currency or financial data, as it provides high precision and allows you to specify the number of decimal places required for accurate calculations.

If you have any other questions or need further clarification, feel free to ask!