- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 07 Jun 2017
Global Unique IDs (GUIDs)
Global Unique IDs (GUIDs, sometimes referred to as universally unique identifiers or UUIDs) are 128-bit numbers used to identify digital information, helping to reference them unambiguously. They are similar to the ISBN numbers used for books.
Because they are so large, GUIDs are virtually guaranteed to be unique. They are formatted in a well-defined sequence of 32 hexadecimal digits grouped as 8-4-4-4-12. This provides roughly 10^38 numbers. An example of how a GUID looks in hexadecimal:
The probability of any two GUID's being the same is very low.
GUIDs can be used to identify information about anything, such as products, papers, webpages, etc.
The general types of GUIDs are:
- Random: A random-number generator creates a 128-bit number.
- Time-based: Based on the current time.
- Hardware-based: Certain parts of the GUID are based on the hardware features, although this removes part of the anonymity of the number.
- Content-based: Based on a hash of the file contents. This can be used if duplicate files need to have the same GUID.
Some of the common uses for GUIDs are as follows:
- Unique primary key in databases (allowing database items to be merged without conflict).
- Unique filenames for uploaded files.
- Unique names for resources.
- Unique IDs for products.
- Unique IDs for design files or models.
The advantages of GUIDs are that there is no central authority, and so no need for management. GUIDs can be generated internally and merged from different data sources with a low chance of any conflict.
However, the GUID itself may be larger than the database item it is keeping track of.
 Related articles on Designing Buildings Wiki
Featured articles and news
There are many ways of classifying types of building. Have a look at our range of building articles.
BSRIA have launched the 'major update' of the go-to design framework guide for building services.
How to get results with building life cycle assessment.
Government publishes a prospectus inviting proposals for new 'garden communities'.
The Morandi motorway bridge in Genoa collapses during rainstorm while undergoing maintenance works.
'Developed design' is a phrase coined by the RIBA for their 2013 Plan of Work. But what does it actually mean?
New green paper published aiming to rebalance the relationship between landlords and residents and tackle stigma.
RIBA calls for a comprehensive ban on combustible materials.
Lump sum contracts can be referred to as ‘fixed price’ contracts, although strictly this is not correct. Find out more here.
Ramboll offer guidance to civil engineers on how to make projects 'off-site ready'.
Government announces its Rough Sleeping Strategy, with further funding for social housing.