Is NUMERIC in Oracle? Decoding Oracle’s Number Types

Yes, the data type NUMERIC is indeed available in Oracle, though it’s more of an ANSI SQL standard alias rather than a core Oracle-specific data type. Oracle internally treats NUMERIC as synonymous with the NUMBER data type, offering flexibility while adhering to SQL standards. This article will delve into the intricacies of number handling in Oracle, answering frequently asked questions to provide a comprehensive understanding for developers and database administrators.

Understanding NUMERIC and NUMBER in Oracle

Oracle’s approach to numeric data types might seem a bit nuanced compared to other database systems. While NUMERIC exists and functions, it’s essentially a wrapper, a familiar face from the SQL standard that maps directly to Oracle’s workhorse: NUMBER.

• NUMBER: This is Oracle’s proprietary, high-precision numeric data type. It can store both fixed-point and floating-point numbers. Its syntax allows you to define precision (total number of digits) and scale (number of digits to the right of the decimal point).

• NUMERIC: As mentioned, NUMERIC is an ANSI SQL standard data type. In Oracle, using NUMERIC(p, s) is precisely equivalent to using NUMBER(p, s). It provides a level of standardization, making it easier to port SQL code between different database systems.

So, in practical terms, whether you declare a column as NUMERIC(10, 2) or NUMBER(10, 2), the underlying storage and behavior in Oracle will be identical.

Benefits of Using NUMERIC in Oracle

Although NUMERIC is essentially an alias for NUMBER in Oracle, using it offers certain advantages:

• Portability: Using NUMERIC in your SQL code makes it more portable across different database systems. If you later decide to migrate your database from Oracle to another platform, using NUMERIC can reduce the amount of code that needs to be rewritten.
• Standardization: Adhering to ANSI SQL standards enhances code readability and maintainability, especially in environments where developers are familiar with those standards.
• Clarity: For developers coming from other database backgrounds, using NUMERIC might provide a more intuitive understanding of the intended data type, especially if they are accustomed to SQL standards.

Potential Drawbacks

The primary drawback is arguably a matter of style and understanding. Developers primarily working within the Oracle ecosystem may find the direct use of NUMBER to be more explicit and readable, reflecting Oracle’s own documentation and practices.

Frequently Asked Questions (FAQs) about NUMERIC in Oracle

Here are 12 frequently asked questions to help clarify the usage and implications of NUMERIC in Oracle.

1. What is the difference between NUMBER, NUMERIC, DECIMAL, and INTEGER in Oracle?

NUMBER is Oracle’s primary numeric data type, offering high precision and flexibility. NUMERIC and DECIMAL are ANSI SQL standard aliases that Oracle internally maps to NUMBER. INTEGER is also an alias, mapped to NUMBER(38,0), meaning it’s a NUMBER with a maximum precision of 38 digits and no decimal places. Therefore, NUMERIC, DECIMAL and INTEGER are all stored and processed in Oracle as variations of NUMBER.

2. How do I specify the precision and scale for NUMERIC in Oracle?

You specify the precision and scale for NUMERIC just like you do for NUMBER: NUMERIC(p, s), where p is the precision (total number of digits) and s is the scale (number of digits to the right of the decimal point). For example, NUMERIC(10, 2) can store numbers with up to 10 digits, with 2 digits after the decimal point.

3. What happens if I try to store a number that exceeds the specified precision or scale for a NUMERIC column?

If you try to store a number that exceeds the defined precision, Oracle will typically return an error (ORA-01438: value larger than specified precision allowed for this column). If the scale is exceeded, Oracle will round the number. For example, if a column is defined as NUMERIC(5,2) and you attempt to insert 123.456, the value will be rounded to 123.46 before being stored. However, inserting 1234.56 would result in the ORA-01438 error.

4. Is there a performance difference between using NUMBER and NUMERIC in Oracle?

No, there is no performance difference. Oracle internally treats NUMERIC as NUMBER, so the storage and processing are identical. The choice between them is purely a matter of coding style and portability considerations.

5. How does NUMERIC handle null values?

NUMERIC columns, like NUMBER columns, can store null values unless explicitly defined as NOT NULL. A null value indicates that the value is unknown or missing.

6. Can I use NUMERIC in PL/SQL?

Yes, you can use NUMERIC in PL/SQL. PL/SQL treats NUMERIC in the same way as it treats NUMBER. You can declare variables, parameters, and return values as NUMERIC just as you would with NUMBER.

7. What are the limitations of using NUMERIC in Oracle?

The limitations are essentially the same as those for NUMBER. The maximum precision allowed is 38 digits. Exceeding this will result in an error. Also, remember that using NUMERIC doesn’t magically provide features beyond those offered by Oracle’s underlying NUMBER type.

8. How can I convert a string to a NUMERIC value in Oracle?

You can use the TO_NUMBER function to convert a string to a NUMERIC value (which, again, is internally stored as NUMBER). For example:

SELECT TO_NUMBER('123.45', '999.99') FROM dual; 

The second argument to TO_NUMBER is the format mask, specifying the expected format of the string.

9. How can I format a NUMERIC value as a string in Oracle?

You can use the TO_CHAR function to format a NUMERIC value as a string. For example:

SELECT TO_CHAR(123.45, '999.99') FROM dual; 

The second argument to TO_CHAR is the format mask, specifying the desired format of the output string.

10. Does Oracle support NUMERIC without specifying precision and scale?

Yes, you can declare a NUMERIC column without specifying precision and scale (simply as NUMERIC). In this case, Oracle defaults to NUMBER, which has a maximum precision of 38 digits and no specified scale. This allows for storing very large numbers with potentially varying decimal places.

11. Can I use NUMERIC with other data types in calculations?

Yes, you can use NUMERIC (and therefore NUMBER) with other numeric data types (like INTEGER, FLOAT, DOUBLE PRECISION) in calculations. Oracle will perform implicit data type conversions as necessary. However, it’s generally good practice to explicitly convert data types using functions like TO_NUMBER to avoid unexpected results.

12. When should I prefer NUMERIC over NUMBER in Oracle?

Prefer NUMERIC when:

• You prioritize portability of your SQL code across different database systems.
• You want to adhere to ANSI SQL standards for better code readability and maintainability, especially in environments where developers have diverse backgrounds.
• You are working on a project where consistent coding style across different database platforms is crucial.

Otherwise, using NUMBER directly is perfectly acceptable and more common within the Oracle development community. Ultimately, the choice often comes down to personal preference and project-specific requirements. The important takeaway is understanding that, in Oracle, they are functionally equivalent.