html_url,issue_url,id,node_id,user,user_label,created_at,updated_at,author_association,body,reactions,issue,issue_label,performed_via_github_app
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1030901189,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1030901189,IC_kwDOCGYnMM49ck3F,9599,simonw,2022-02-06T19:48:36Z,2022-02-06T19:48:52Z,OWNER,"From [that thread](https://github.com/simonw/sqlite-utils/issues/399#issuecomment-1030739566), two extra ideas which it may be possible to support in a single implementation:
```python
from sqlite_utils.conversions import LongitudeLatitude
db[""places""].insert(
{
""name"": ""London"",
""lng"": -0.118092,
""lat"": 51.509865,
},
conversions={""point"": LongitudeLatitude(""lng"", ""lat"")},
)
```
And
```python
db[""places""].insert(
{
""name"": ""London"",
""point"": LongitudeLatitude(-0.118092, 51.509865)
}
)
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1030901853,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1030901853,IC_kwDOCGYnMM49clBd,9599,simonw,2022-02-06T19:52:10Z,2022-02-06T19:52:10Z,OWNER,"So the key idea here is to introduce a new abstract base class, `Conversion`, which has the following abilities:
- Can wrap one or more Python values (if called using the constructor) such that the `.insert_all()` method knows how to transform those into a format that can be included in an insert - something like `GeomFromText(?, 4326)` with input `POINT(-0.118092 51.509865)`
- Can be passed to `conversions={""point"": LongitudeLatitude}` in a way that then knows to apply that conversion to every value in the `""point""` key of the data being inserted.
- Maybe also extend `conversions=` to allow the definition of additional keys that use as input other rows? That's the `conversions={""point"": LongitudeLatitude(""lng"", ""lat"")}` example above - it may not be possible to get this working with the rest of the design though.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1030902102,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1030902102,IC_kwDOCGYnMM49clFW,9599,simonw,2022-02-06T19:53:34Z,2022-02-08T07:40:34Z,OWNER,"I like the idea that the contract for `Conversion` (or rather for its subclasses) is that it can wrap a Python value and then return both the SQL fragment - e.g. `GeomFromText(?, 4326)` - and the values that should be used as the SQL parameters.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1030904948,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1030904948,IC_kwDOCGYnMM49clx0,9599,simonw,2022-02-06T20:09:42Z,2022-02-08T07:40:44Z,OWNER,"I think this is the code that needs to become aware of this system: https://github.com/simonw/sqlite-utils/blob/fea8c9bcc509bcae75e99ae8870f520103b9aa58/sqlite_utils/db.py#L2453-L2469
There's an earlier branch that runs for upserts which needs to be modified too: https://github.com/simonw/sqlite-utils/blob/fea8c9bcc509bcae75e99ae8870f520103b9aa58/sqlite_utils/db.py#L2417-L2440","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1031779460,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1031779460,IC_kwDOCGYnMM49f7SE,25778,eyeseast,2022-02-07T18:24:56Z,2022-02-07T18:24:56Z,CONTRIBUTOR,"I wonder if there's any overlap with the goals here and the `sqlite3` module's concept of adapters and converters: https://docs.python.org/3/library/sqlite3.html#sqlite-and-python-types
I'm not sure that's _exactly_ what we're talking about here, but it might be a parallel with some useful ideas to borrow.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1031787865,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1031787865,IC_kwDOCGYnMM49f9VZ,9599,simonw,2022-02-07T18:33:27Z,2022-02-07T18:33:27Z,OWNER,"Hah, that's interesting - I've never used that mechanism before so it wasn't something that came to mind.
They seem to be using a pretty surprising trick there that takes advantage of SQLite allowing you to define a column ""type"" using a made-up type name, which you can then introspect later.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1031791783,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1031791783,IC_kwDOCGYnMM49f-Sn,25778,eyeseast,2022-02-07T18:37:40Z,2022-02-07T18:37:40Z,CONTRIBUTOR,"I've never used it either, but it's interesting, right? Feel like I should try it for something.
I'm trying to get my head around how this conversions feature might work, because I really like the idea of it.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1032294365,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1032294365,IC_kwDOCGYnMM49h4_d,9599,simonw,2022-02-08T07:32:09Z,2022-02-08T07:34:41Z,OWNER,"I have an idea for how that third option could work - the one that creates a new column using values from the existing ones:
```python
db[""places""].insert(
{
""name"": ""London"",
""lng"": -0.118092,
""lat"": 51.509865,
},
conversions={""point"": LongitudeLatitude(""lng"", ""lat"")},
)
```
How about specifying that the values in that `conversion=` dictionary can be:
- A SQL string fragment (as currently implemented)
- A subclass of `Conversion` as described above
- Or... a callable function that takes the row as an argument and returns either a `Conversion` subclass instance or a literal value to be jnserted into the database (a string, int or float)
Then you could do this:
```python
db[""places""].insert(
{
""name"": ""London"",
""lng"": -0.118092,
""lat"": 51.509865,
},
conversions={
""point"": lambda row: LongitudeLatitude(
row[""lng""], row[""lat""]
)
}
)
```
Something I really like about this is that it expands the abilities of `conversions=` beyond the slightly obscure need to customize the SQL fragment into something that can solve other data insertion cleanup problems too.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1032296717,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1032296717,IC_kwDOCGYnMM49h5kN,9599,simonw,2022-02-08T07:35:46Z,2022-02-08T07:35:46Z,OWNER,"I'm going to write the documentation for this first, before the implementation, so I can see if it explains cleanly enough that the design appears to be sound.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1032732242,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1032732242,IC_kwDOCGYnMM49jj5S,25778,eyeseast,2022-02-08T15:26:59Z,2022-02-08T15:26:59Z,CONTRIBUTOR,"What if you did something like this:
```python
class Conversion:
def __init__(self, *args, **kwargs):
""Put whatever settings you need here""
def python(self, row, column, value): # not sure on args here
""Python step to transform value""
return value
def sql(self, row, column, value):
""Return the actual sql that goes in the insert/update step, and maybe params""
# value is the return of self.python()
return value, []
```
This way, you're always passing an instance, which has methods that do the conversion. (Or you're passing a SQL string, as you would now.) The `__init__` could take column names, or SRID, or whatever other setup state you need per row, but the row is getting processed with the `python` and `sql` methods (or whatever you want to call them). This is pretty rough, so do what you will with names and args and such.
You'd then use it like this:
```python
# subclass might be unneeded here, if methods are present
class LngLatConversion(Conversion):
def __init__(self, x=""longitude"", y=""latitude""):
self.x = x
self.y = y
def python(self, row, column, value):
x = row[self.x]
y = row[self.y]
return x, y
def sql(self, row, column, value):
# value is now a tuple, returned above
s = ""GeomFromText(POINT(? ?))""
return s, value
table.insert_all(rows, conversions={""point"": LngLatConversion(""lng"", ""lat""))}
```
I haven't thought through all the implementation details here, and it'll probably break in ways I haven't foreseen, but wanted to get this idea out of my head. Hope it helps.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1033366312,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1033366312,IC_kwDOCGYnMM49l-so,9599,simonw,2022-02-09T05:28:11Z,2022-02-09T07:28:48Z,OWNER,"My hunch is that the case where you want to consider input from more than one column will actually be pretty rare - the only case I can think of where I would want to do that is for latitude/longitude columns - everything else that I'd want to use it for (which admittedly is still mostly SpatiaLite stuff) works against a single value.
The reason I'm leaning towards using the constructor for the values is that I really like the look of this variant for common conversions:
```python
db[""places""].insert(
{
""name"": ""London"",
""boundary"": GeometryFromGeoJSON({...})
}
)
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1033428967,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1033428967,IC_kwDOCGYnMM49mN_n,9599,simonw,2022-02-09T07:25:44Z,2022-02-09T07:28:11Z,OWNER,"The CLI version of this could perhaps look like this:
sqlite-utils insert a.db places places.json \
--conversion boundary GeometryGeoJSON
This will treat the boundary key as GeoJSON. It's equivalent to passing `conversions={""boundary"": geometryGeoJSON}`
The combined latitude/longitude case here can be handled by combining this with the existing `--convert` mechanism.
Any `Conversion` subclass will be available to the CLI in this way.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1035057014,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1035057014,IC_kwDOCGYnMM49sbd2,25778,eyeseast,2022-02-10T15:30:28Z,2022-02-10T15:30:40Z,CONTRIBUTOR,"Yeah, the CLI experience is probably where any kind of multi-column, configured setup is going to fall apart. Sticking with GIS examples, one way I might think about this is using the [fiona CLI](https://fiona.readthedocs.io/en/latest/cli.html):
```sh
# assuming a database is already created and has SpatiaLite
fio cat boundary.shp | sqlite-utils insert boundaries --conversion geometry GeometryGeoJSON -
```
Anyway, very interested to see where you land here.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,
https://github.com/simonw/sqlite-utils/issues/402#issuecomment-1041325398,https://api.github.com/repos/simonw/sqlite-utils/issues/402,1041325398,IC_kwDOCGYnMM4-EV1W,82988,psychemedia,2022-02-16T10:12:48Z,2022-02-16T10:18:55Z,NONE,"> My hunch is that the case where you want to consider input from more than one column will actually be pretty rare - the only case I can think of where I would want to do that is for latitude/longitude columns
Other possible pairs: unconventional date/datetime and timezone pairs eg `2022-02-16::17.00, London`; or more generally, numerical value and unit of measurement pairs (eg if you want to cast into and out of different measurement units using packages like `pint`) or currencies etc. Actually, in that case, I guess you may be presenting things that are unit typed already, and so a conversion would need to parse things into an appropriate, possibly two column `value, unit` format.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1125297737,Advanced class-based `conversions=` mechanism,