What Is Number Data Type in PostgreSQL?
In PostgreSQL, the number data type is used to store numeric values. It provides a way to represent both integer and floating-point numbers. This data type is essential for various types of calculations and mathematical operations in database applications.
Integer Data Type
The integer data type in PostgreSQL allows you to store whole numbers without any fractional component. It can represent both positive and negative values. The range of values that can be stored as an integer depends on the storage size, which can be 2 bytes, 4 bytes, or 8 bytes.
To define a column with the integer data type, you can use the integer keyword or its alias int. Here’s an example:
CREATE TABLE employees ( employee_id serial PRIMARY KEY, age int );
Floating-Point Data Types
If you need to store numbers with fractional components or decimal points, PostgreSQL provides several floating-point data types:
1. Real Data Type
The real data type allows you to store single-precision floating-point numbers. It occupies 4 bytes of storage and provides a reasonable level of precision for most applications.
CREATE TABLE products ( product_id serial PRIMARY KEY, price real );
2. Double Precision Data Type
The double precision data type provides double-precision floating-point numbers. It offers higher precision compared to the real data type but requires twice as much storage space (8 bytes).
CREATE TABLE products ( product_id serial PRIMARY KEY, price double precision );
Numeric Data Type
The numeric data type in PostgreSQL allows you to store arbitrary precision numbers. It can represent numbers with a large number of digits before and after the decimal point without losing precision.
To define a column with the numeric data type, you need to specify the precision (total number of digits) and scale (number of digits after the decimal point). Here’s an example:
CREATE TABLE transactions ( transaction_id serial PRIMARY KEY, amount numeric(10, 2) );
In this example, the amount column can store a total of 10 digits, with 2 digits after the decimal point. This allows for precise representation of monetary values.
In summary, PostgreSQL provides various number data types to cater to different requirements. The integer data type is suitable for storing whole numbers, while the real and double precision data types are ideal for floating-point numbers. For arbitrary precision calculations, the numeric data type is recommended.
By understanding these number data types in PostgreSQL, you can make informed decisions when designing your database schema and ensure accurate representation of numerical values in your applications.