Proposal/Enhancement for Nominal pressure

[tudorbarascu]

The materials and the nominal pressure combinations that we have in the materials table do not fully cover whatever is in the field. I remembered that we even considered dropping the PN column but we were a little stuck on account of this.

My proposal is to begin using the pressure_nominal column with the following convention:

• for a PE 110 Pipe of 10 PN material the pressure_nominal column shouldn't be used (NULL) as we already have it from the materials table. However, in case the pipe is old or we consider it's not in the best shape due to various reasons and we want to restrict the nominal pressure to 8 let's say, by filling the pressure_nominal column we override by convention the PN. So, although the pipe material is 10, we consider the pipe to have PN of 8.
• This would also solve the cases where the material tables is lacking some combinations between materials and PN (for various reasons: no standards etc.) where we can put the PN in the pressure_nominal.

Related to #87 and #21

Thoughts anyone?

[tudorbarascu]

Also, IMHO we shouldn't enforce the pressure_nominal default to 16 (or any other) in the db model but this should be moved to the QGIS side of the project.

[haubourg]

ping @qwat/qwat-psc