html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,issue,performed_via_github_app https://github.com/simonw/sqlite-utils/issues/411#issuecomment-1065597709,https://api.github.com/repos/simonw/sqlite-utils/issues/411,1065597709,IC_kwDOCGYnMM4_g7sN,9599,2022-03-11T22:32:43Z,2022-03-11T22:32:43Z,OWNER,"Trying to figure out what that extra field in `table_info` compared to `table_xinfo` is: ``` >>> list(db.query(""PRAGMA table_xinfo('t')"")) [{'cid': 0, 'name': 'body', 'type': 'TEXT', 'notnull': 0, 'dflt_value': None, 'pk': 0, 'hidden': 0}, {'cid': 1, 'name': 'd', 'type': 'INT', 'notnull': 0, 'dflt_value': None, 'pk': 0, 'hidden': 2}] `` Presumably `hidden` 0 v.s 2 v.s. other values has meaning.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1160034488, https://github.com/simonw/sqlite-utils/issues/411#issuecomment-1065596417,https://api.github.com/repos/simonw/sqlite-utils/issues/411,1065596417,IC_kwDOCGYnMM4_g7YB,9599,2022-03-11T22:30:15Z,2022-03-11T22:30:15Z,OWNER,"I tried it out in Jupyter and it works as advertised: Introspection is a bit weird: there doesn't seem to be a way to introspect generated columns outside of parsing the stored SQL schema for the columns at the moment! And the `.columns` method doesn't return them at all: https://github.com/simonw/sqlite-utils/blob/433813612ff9b4b501739fd7543bef0040dd51fe/sqlite_utils/db.py#L1207-L1213 Here's why: ``` >>> db.execute(""PRAGMA table_info('t')"").fetchall() [(0, 'body', 'TEXT', 0, None, 0)] >>> db.execute(""PRAGMA table_xinfo('t')"").fetchall() [(0, 'body', 'TEXT', 0, None, 0, 0), (1, 'd', 'INT', 0, None, 0, 2)] ``` So `table_xinfo()` is needed to get back columns including generated columns: https://www.sqlite.org/pragma.html#pragma_table_xinfo > **PRAGMA** *schema.***table_xinfo(***table-name***);** > > This pragma returns one row for each column in the named table, including [hidden columns](https://www.sqlite.org/vtab.html#hiddencol) in virtual tables. The output is the same as for [PRAGMA table_info](https://www.sqlite.org/pragma.html#pragma_table_info) except that hidden columns are shown rather than being omitted.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1160034488, https://github.com/simonw/sqlite-utils/issues/411#issuecomment-1065402557,https://api.github.com/repos/simonw/sqlite-utils/issues/411,1065402557,IC_kwDOCGYnMM4_gMC9,9599,2022-03-11T19:01:08Z,2022-03-11T21:42:25Z,OWNER,"Just spotted this in https://www.sqlite.org/gencol.html > The only functional difference is that one cannot add new STORED columns using the [ALTER TABLE ADD COLUMN](https://www.sqlite.org/lang_altertable.html#altertabaddcol) command. Only VIRTUAL columns can be added using ALTER TABLE. So to add stored columns to an existing table we would need to use the `.transform()` trick. Which implies that this should actually be a capability of the various `.create()` methods, since transform works by creating a new table with those and then copying across the old data. Here's where `.transform()` calls `.create_table_sql()` under the hood: https://github.com/simonw/sqlite-utils/blob/9388edf57aa15719095e3cf0952c1653cd070c9b/sqlite_utils/db.py#L1627-L1637","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1160034488, https://github.com/simonw/sqlite-utils/issues/411#issuecomment-1065389386,https://api.github.com/repos/simonw/sqlite-utils/issues/411,1065389386,IC_kwDOCGYnMM4_gI1K,9599,2022-03-11T18:42:53Z,2022-03-11T21:40:51Z,OWNER,"The Python API could be: ```python db[table_name].add_generated_column(""field"", str, ""json_extract(data, '$.field')"", stored=True) ```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1160034488, https://github.com/simonw/sqlite-utils/issues/411#issuecomment-1065458729,https://api.github.com/repos/simonw/sqlite-utils/issues/411,1065458729,IC_kwDOCGYnMM4_gZwp,9599,2022-03-11T19:58:50Z,2022-03-11T20:00:25Z,OWNER,"I'm coming round to your suggestion to have this as extra arguments to `sqlite-utils add-column` now, especially since you also need to pass a column type. I'd like to come up with syntax for `sqlite-utils create-table` as well. https://sqlite-utils.datasette.io/en/stable/cli-reference.html#create-table Maybe extra `--generated-stored colname expression` (and `--generated`) options would work there.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1160034488, https://github.com/simonw/sqlite-utils/issues/411#issuecomment-1065440445,https://api.github.com/repos/simonw/sqlite-utils/issues/411,1065440445,IC_kwDOCGYnMM4_gVS9,9599,2022-03-11T19:52:15Z,2022-03-11T19:52:15Z,OWNER,"Two new parameters to `.create_table()` and friends: - `generated={...}` - generated column definitions - `generated_stored={...}` generated stored column definitions These columns will be added at the end of the table, but you can use the `column_order=` parameter to apply a different order.","{""total_count"": 1, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 1, ""rocket"": 0, ""eyes"": 0}",1160034488, https://github.com/simonw/sqlite-utils/issues/411#issuecomment-1065386352,https://api.github.com/repos/simonw/sqlite-utils/issues/411,1065386352,IC_kwDOCGYnMM4_gIFw,9599,2022-03-11T18:41:37Z,2022-03-11T18:41:37Z,OWNER,"I like `add-generated-column` - feels very clear to me, and is a nice place for adding logic that checks if the DB version supports it or not and shows a useful error.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1160034488,