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PostgreSQL UUID

Updated May 24, 2023

PostgreSQL UUID

 

 

Introduction to PostgreSQL UUID

PostgreSQL UUID is also known as a universally unique identifier; it is used to generate a unique value within a database. RFC 4122 standards in PostgreSQL define it; the Value of UUID is 128 bit, generated by an algorithm that makes the unique identifier number within the database. UUID is mainly used in distributed application databases to generate a unique number within the database because UUID is more unique than a serial data type. The UUID data type is unique as compared to the serial data type.

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Syntax

Below is the syntax of the data type as follows.

1. Syntax of creating a table using data type.

CREATE TABLE table_name(
Column_name uuid DEFAULT uuid_generate_v4(),
Column_namedata type NOT NULL,
Column_nameData type,
PRIMARY KEY (column_name));

2. SELECT uuid_generate_v1() (Generating UUID using a combination of MAC address of Computer, timestamp, and random value);

3. SELECT uuid_generate_v4 () (Generating UUID by using only random numbers.);

Below is the parameter description of the above syntax.

  1. Column 1 to column N – Column 1 to column N, used in the table on which we created a UUID data type in PostgreSQL. We can create a UUID data type on the column using the uuid_generate_v1 and uuid_generate_v4 functions.
  2. Table name – The table name creates a new table using a UUID data type on the column. We can create a UUID data type on the column.
  3. Create – Create a keyword used to create a new table using a UUID data type on the column.
  4. Data type – We can define different data types for the different columns while creating a table.
  5. Primary key – We have created a primary key on the UUID column; while creating a new table, we can also create a primary key later in the column.
  6. Select – Select is used to select the UUID data type in PostgreSQL. We can select a value of uuid_generate_v1 and uuid_generate_v4 data type functions by using a select statement.
  7. uuid_generate_v1 – This is defined as a generated UUID number using a combination of the computer’s Mac address, the current timestamp, and any random number. We can generate a UUID number by using this function. To use this function, we need to create an extension of UUID-OSSP in PostgreSQL.
  8. uuid_generate_v4 – This is defined as generating UUID numbers using only random numbers. We can generate a UUID number by using this function. To use this function, we need to create an extension of UUID-OSSP in PostgreSQL.

How does UUID data type work in PostgreSQL?

Below is the working of the data type.

  • To use the UUID function, we need to create an extension of UUID-OSSP in PostgreSQL.
  • The below example states that to create an extension of UUID-OSSP is as follows.
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

PostgreSQL UUID output 1

  • The above command creates a UUID-OSSP extension if it does not exist in the database. By default, this extension is unavailable; we need to create this after installation to use a UUID data type.
  • A universally unique identifier serves as an identifier used for generating a unique value within a database.
  • The UUID data type is unique as compared to the serial data type.
  • PostgreSQL follows the RFC 4122 standards for UUIDs. PostgreSQL generates a UUID as a 128-bit value using an algorithm that guarantees uniqueness within the database, thus making it a unique identifier.
  • Distributed application databases often utilize UUIDs to generate unique numbers within the database. The preference for UUIDs over serial data types in PostgreSQL stems from their higher level of uniqueness.
  • The UUID consists of a sequence of 32-bit hexadecimal digits separated by hyphens.
  • It is more unique than a serial in PostgreSQL because it is a 32-bit combination of hexadecimal numbers.
  • There are two functions of UUID data types.
  1. uuid_generate_v1 ()
  2. uuid_generate_v4 ()
  • Uuid_generate_v1 generates a UUID number by combining the computer’s Mac address, current timestamp, and any random number. We can generate a UUID number by using this function in PostgreSQL. To use this function, we need to create an extension of UUID-OSSP in PostgreSQL.
  • Uuid_generate_v4 defines as a generate UUID number by using only a random number. We can generate a UUID number by using this function. To use this function, we need to create an extension of UUID-OSSP in PostgreSQL.

Examples

Below is an example of the UUID data type in PostgreSQL is as follows.

1. uuid_generate_v1 () – We can see the value of uuid_generate_v1 () as below. Below is the value of the uuid_generate_v1 () function.

select uuid_generate_v1 ();

PostgreSQL UUID output 2

2. uuid_generate_v4 () –We can see the value of uuid_generate_v4 () as below. Below is the value of the uuid_generate_v4 () function.

select uuid_generate_v4 ();

output 3

3. Define UUID data type at the time of table creation

In the example below, we have to create a table and insert value using the UUID data type.

Create table –

CREATE TABLE Employee_UUID (emp_id uuid DEFAULT uuid_generate_v1(),emp_name character(10) NOT NULL, emp_address character(20) NOT NULL, emp_phone character(14),emp_salary INT NOT NULL, date_of_joining date NOT NULL);

output 4

Insert Value –

INSERT INTO Employee_UUID (emp_name, emp_address, emp_phone, emp_salary, date_of_joining) VALUES ('ABC', 'Pune', '1234567890', 20000, '01-01-2020');
INSERT INTO Employee_UUID (emp_name, emp_address, emp_phone, emp_salary, date_of_joining) VALUES ('PQR', 'Pune', '1234567890', 20000, '01-01-2020');
INSERT INTO Employee_UUID (emp_name, emp_address, emp_phone, emp_salary, date_of_joining) VALUES ('XYZ', 'Mumbai', '1234567890', 35000, '02-01-2020');
select * from Employee_UUID;

output 5

Advantages of using UUID in PostgreSQL

  • Below are the advantages of the PostgreSQL UUID data type are as follows.
  • PostgreSQL UUID data type is used to generate a sequential number.
  • The UUID data type is more unique than the serial data type.
  • The UUID data type will generate a 32-bit sequential value, so it is more unique.
  • Performance is faster than other serial data types.
  • We can use an alternate function to create a UUID.

Conclusion

A universally unique identifier (UUID) serves as an identifier used for generating a unique value within a database. The UUID data type is unique as compared to a serial data type.PostgreSQL UUID, as defined by RFC 4122 standards, the Value of UUID is 128 bit.

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