What is SQL UUID?

This function in MySQL is used to return a Universal Unique Identifier (UUID) generated according to RFC 4122, “A Universally Unique Identifier (UUID) URN Namespace”. It is designed as a number that is universally unique. Two UUID values are expected to be distinct, even they are generated on two independent servers.

What is UUID in database?

A UUID is a Universal Unique Identifier specified by RFC 4122 (It is a Universally Unique Identifier URN Namespace) and 128-bit long value. It is designed in such a way that it generates a number which is unique globally according to space and time.

What is a UUID example?

Format. In its canonical textual representation, the 16 octets of a UUID are represented as 32 hexadecimal (base-16) digits, displayed in five groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters (32 hexadecimal characters and 4 hyphens). For example: 123e4567-e89b-12d3-a456-426614174000.

Why should I use UUID?

The point of a UUID is to have a universally unique identifier. There’s generally two reason to use UUIDs: You do not want a database (or some other authority) to centrally control the identity of records. There’s a chance that multiple components may independently generate a non-unique identifier.

Should I use UUID in database?

If your database is or will eventually be distributed, like in the case of a local-first application, or simply if your NoSQL database is scaling up and divided upon multiple servers, I’d say that you have almost non choice : Use UUID! Just know that there is some things that you can do to improve performance.

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How does a UUID work?

How does UUID work? The UUID relies on a combination of components to ensure uniqueness. UUIDs are constructed in a sequence of digits equal to 128 bits. The ID is in hexadecimal digits, meaning it uses the numbers 0 through 9 and letters A through F.

Does MySQL have UUID?

UUID() function in MySQL

It is designed as a number that is universally unique. Two UUID values are expected to be distinct, even they are generated on two independent servers. In MySQL, a UUID value is a 128-bit number represented as a utf8 string, and the format in hexadecimal number will be as follows.

Is UUID safe?

UUIDs are safe enough for nearly all practical purposes1, and certainly for yours.

What UUID to use?

If you need to generate reproducible UUIDs from given names, you want a version 3 or version 5. Version 3: This generates a unique ID from an MD5 hash of a namespace and name. If you need backwards compatibility (with another system that generates UUIDs from names), use this.

Is UUID efficient?

The default representation for UUID, hash, and token values is often the hexadecimal notation. With a cardinality, the number of possible values, of only 16 per byte, it is far from efficient.

Is UUID number or string?

UUIDs are an octet string of 16 octets (128 bits). The 16 octets can be interpreted as an unsigned integer encoding, and the resulting integer value can be used as a subsequent arc of {joint-iso-itu-t uuid(25)} (or 2.25) in the OID tree.

Is it OK to use UUID as primary key?

Using UUID for a primary key brings the following advantages: UUID values are unique across tables, databases, and even servers that allow you to merge rows from different databases or distribute databases across servers. UUID values do not expose the information about your data so they are safer to use in a URL.

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Can UUID collide?

A collision is possible but the total number of unique keys generated is so large that the possibility of a collision is almost zero. As per Wikipedia, the number of UUIDs generated to have atleast 1 collision is 2.71 quintillion. This is equivalent to generating around 1 billion UUIDs per second for about 85 years.