fix(sql-browser): rank the row-selector candidate so a date-only column is a last resort (Driver.Sql.Browser-001)

PreferredTimestampColumn nominated the first column mapping to DriverDataType
.DateTime, and that set includes date-only types (SQL Server / PostgreSQL
'date'). A table whose first date/time column is a 'date' committed
rowSelector.topByTimestamp = <date>, making the wide-row read ORDER BY <date>
DESC LIMIT 1 - which ties for every row written that day, so 'the newest row'
became storage order among the ties.

Time-bearing candidates now outrank date-only ones; a date-only column is still
stated when it is all the table has, so such a table stays bindable. Oracle's
DATE carries a time of day and is exempt - pinned by a control dialect that
differs from the SQLite one only in the Provider it reports.
This commit is contained in:
Joseph Doherty
2026-08-10 07:59:35 -04:00
parent 073930e023
commit a8cfc886a3
5 changed files with 254 additions and 11 deletions
+12 -3
View File
@@ -190,14 +190,23 @@ commit writes as `rowSelector.topByTimestamp` ("read the newest row"). Before th
a selector-less blob that `SqlEquipmentTagParser` and the authoring gate both refuse, so no
browse-committed Sql tag was ever readable.
Two properties of the choice are deliberate:
Three properties of the choice are deliberate:
- **Candidacy is by declared TYPE, never by column name.** The session asks
`ISqlDialect.MapColumnType` for `DriverDataType.DateTime` — the same metadata the browse tree already
renders per column. A name heuristic (`*_ts`, `*time*`) would happily order a wide-row read by a
*string* column called `timestamp`, binding the tag to whichever row sorts last lexically.
- **The tie-break is first in catalog order** (every dialect's column query orders by ordinal
position), so the pick is stable across calls, connections and servers. On a
- **Candidates are RANKED: a time-bearing type beats a date-only one.** `MapColumnType` reports
`DriverDataType.DateTime` for SQL Server's and PostgreSQL's `date` too, and ordering a single-row read
by a date-only column ties for *every row written on the same day* — "the newest row" quietly becomes
storage order among the ties, and the reader cannot warn about it because the server has already
discarded the others. So a `datetime2`/`timestamptz`/… column wins over a `date` one wherever both
exist, regardless of declaration order. A date-only column is still stated when it is **all** the table
has, so such a table stays bindable by browse rather than becoming un-committable.
**Oracle's `DATE` is exempt** — it carries a time-of-day component (which is why `OracleDialect` maps
it faithfully rather than as a widening), so it is not demoted there.
- **The tie-break within a rank is first in catalog order** (every dialect's column query orders by
ordinal position), so the pick is stable across calls, connections and servers. On a
`CreatedUtc`/`ModifiedUtc` pair it takes the earlier-declared one. It is a **visible, editable
default**: the typed editor shows the selector and the operator can change it — to the other
timestamp, or to a `whereColumn`/`whereValue` pair entirely.