Advanced SQL

[azahnen]

Adds support for custom SQL expressions and other join types than INNER.

Examples

areaValue:
  sourcePath: "[EXPRESSION]{sql=$T$.afl+55.5}"
  type: FLOAT

geometrie:
   sourcePath: "[sch=schl]katasterbezirk{joinType=LEFT}/geometrie"

Todo

• issue
• docs
• disable queryable and sortable for expression properties

[cportele]

@azahnen

I have updated the sourcepath of abschnitteaeste/laenge_m in strassen to "[EXPRESSION]{sql=$T$.laenge+55}". Accessing the /strassen/collections/abschnitteaeste/items the following query is executed:

SELECT A.fid AS SKEY, A.abs, A.strbez, A.strkl, A.strnr, A.strzus, A.absnr, A.absast, A.statanf, SQL__1, A.vwbez, A.vwbezknz, datetime(A.netzstand), ST_AsText(ST_ForcePolygonCCW(A.geom)) FROM abschnitteaeste_line A WHERE (A.fid >= 1 AND A.fid <= 10) ORDER BY 1

The SQL__1 results in an error.

I have copied the "$T$." from the example above, but I do not understand what this means or if it is necessary. I have also tried it with {sql=laenge+55}, but the change had no effect on the behavior.

[azahnen]

@cportele This was not implemented yet for GPKG.

[cportele]

@azahnen - Expressions are now working as expected.

Do you have an example, where a left/right/full join makes sense? I could not come up with an example.

[azahnen]

@cportele After further thought, I don't think there is a use case for left/right/full join at the moment. The reason for that is that for every join a separate query will be generated. But there are plans for query optimizations where all joins for non-multiple properties would be merged into the main query. In that case the option would become meaningful.

So I still think it makes sense to introduce the option now and use it in the hale plugin to make the generated configurations future-proof in that regard. But it might be confusing to have an option without any current use case in the docs. So should we make it a hidden option for now?

[cportele]

@azahnen - Yes, I think we should hide this option, at least for now.

[azahnen]

@cportele I removed the docs paragraph for the option.