FieldtypeDecimal needs to be in the core

[szabeszg]

Well, what can I say? This is a must.

The issue is detailed here:
https://processwire.com/talk/topic/7542-development-fieldtypefloat-fieldtypedecimal/

Fork I happen to use:
https://processwire.com/talk/topic/7542-development-fieldtypefloat-fieldtypedecimal/?do=findComment&comment=139097

Text fields are not a solution but a workaround. Please consider solving it by adding FieldtypeDecimal to the core. It might need some clean up before it can be added but I think it is worth the effort.

It is such an important issue that it should not be left to third party development.

[teppokoivula]

+1 for this request. While float is useful for many use cases and has better performance, it is not a good choice for storing exact (or large) numbers.

[arjenblokzijl]

+1 for every calculation which needs precision we use decimals.

[kiwigringo]

+1. This is a standard data type for almost every SQL dialect for reasons already described.
To make Processwire a viable contender for financial calculations particularly, this needs to be a core feature.

[BernhardBaumrock]

+1 :)

[zoeck-dev]

+1 ;)

[netcarver]

Have to agree. +1

[jmartsch]

Please implement this.

[kongondo]

+1 for the request, please. Will be useful for Padloper as well. Thanks.

[NikoTechnik]

+1 Please Implement!

[flydev-fr]

I agree too. +1

float a = 0.15 + 0.15
float b = 0.1 + 0.2
if(a == b) // can be false!
if(a >= b) // can also be false!

Meanwhile...

What can I do to avoid this problem?

If you really need your results to add up exactly, especially when you work with money: use a special decimal datatype.
If you just don’t want to see all those extra decimal places: simply format your result rounded to a fixed number of decimal places when displaying it.
If you have no decimal datatype available, an alternative is to work with integers, e.g. do money calculations entirely in cents. 

The Floating Point Guide

[LostKobrakai]

While I'm all for having a nicely working decimal fieldtype in the ecosystem I've yet to see a reason why this needs to be in the core specifically. Decimals are important, but only to certain types of applications. Maybe someone can describe what's missing from the current module, which could only be fixed by adding it to the core or adding some capability to the core, which is missing by now.

[BernhardBaumrock]

Valid point. I wanted to comment that I think there should at least be a note or warning on the float fieldtype but then I went ahead and just created that as PR: processwire/processwire#130

I also created a tutorial of how to submit PRs so that maybe others can contribute easier and faster: https://processwire.com/talk/topic/20423-how-to-submit-pull-requests-to-the-processwire-core/

[flydev-fr]

I don't think that a warning on the InputfieldFloat is needed here, but as a note in the documentation as I expect that a programmer know what is a Floating-point type, as it's the same story for others programming language.

I think it could might be worth writing an article on ProcessWire about, e.g., how to work with financial data, using decimal or integer type but not float and explaining performance issues doing calculations on a decimal type.

[szabeszg]

C'mon guys :) we are talking about ProcessWire which is supposed to ease PHP development. We might as well argue that there is no need for "jQuery style selectors" we only need to educate people about the PDO class. I could come up with hundreds of other similar examples, of course.

This is a popular request, it can be turned down by saying: just learn more about PHP but I do not think this is the way to go. Loads and loads of extra features have been added since this request was posted, features we could also live without. Why this is the questionable one?