The RTU framer overloaded DesyncReason.TruncatedFrame for three distinct
failures — a genuine short read, a CRC-16 validation failure, and a
CRC-valid reply from the wrong RS-485 slave. Split the latter two into
dedicated CrcMismatch / UnitMismatch enum members so a future .Reason
consumer (metrics, operator diagnostics) can tell a wiring/EMI CRC fault
apart from a mis-addressed multi-drop reply. Behaviour is unchanged — all
three still throw ModbusTransportDesyncException and tear the socket down.
Framing tests now assert the specific Reason on each path.
Follow-up #12 from the Modbus RTU-over-TCP plan.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Read-only Sql Equipment-kind driver: polls SQL Server tables/views on an
interval and publishes selected columns/rows as OPC UA variable nodes. Three
projects mirror the Modbus split (Contracts / runtime / Browser); ISqlDialect
seam (SqlServer only in v1); grouped one-query-per-source reads with a
three-layer client-side deadline; schema-walk address picker; typed AdminUI
driver-config + tag-config editors; env-gated central-SQL integration + a
dedicated-container blackhole gate.
Live /run gate PASSED end-to-end on docker-dev: authored a Sql driver +
device + KeyValue tag through the AdminUI, deployed, and read the live value
(dbo.TagValues.Line1.Speed = 42.5, Good) back over OPC UA.
Follow-ups filed: Gitea #496 (§8.1 catalog gate), #497 (cross-driver status
codes), #498 (connectionString persist guard).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Adds the named connection-string ref the Sql poll driver resolves
(connectionStringRef: "DevSql") to both central nodes' env, pointing at a
DevSql database on the rig's own sql container. Committed-dev-secret exception,
same posture as the ConfigDb line above it. This is the env wiring the Task 21
live /run gate used to author + deploy a Sql driver and read a live value
(dbo.TagValues.Line1.Speed = 42.5) back over OPC UA.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The read-only Sql driver's runtime factory/probe and tag-side editors were
wired, but the AdminUI could not author the DRIVER: the /raw "New driver" type
list, the DriverConfigModal switch, and the legacy identity dropdown all omitted
Sql, and no SqlDriverForm existed. Live-driving the AdminUI surfaced this.
- Add SqlDriverForm.razor over the SqlDriverConfigDto shape: Provider
(SqlServer-only in v1), required connectionStringRef (an env-var NAME, not a
connection string — label is explicit), optional poll/operation/command
timeouts, maxConcurrentGroups, nullIsBad. Enums serialize by NAME via
JsonStringEnumConverter; a connection-string literal can never be authored
(no such field is collected); rawTags (composer-owned) + allowWrites (inert,
read-only v1) are never emitted.
- Wire Sql into DriverConfigModal switch, RawDriverTypeDialog type list, and
DriverIdentitySection legacy dropdown.
- Add SqlDriverFormContractTests: the exact JSON the form emits constructs a
driver through the real factory, missing connectionStringRef is rejected, and
provider round-trips as the "SqlServer" name (never an ordinal).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The C1 credential-hygiene fix converted InitializeAsync and ReadAsync to
surface only ex.GetType().Name, but left HandlePollError building its
operator-facing Degrade() message from raw ex.Message, gated only by
'if (ex is DbException) return;'. That guard exists for the I1
double-classification concern, not for message safety, and it is incomplete
for the leak vector: a malformed connection string throws ArgumentException
from the keyword parser (the same unquoted-';'-in-password shape the sibling
SqlDriverBrowser.Sanitize special-cases), which is not a DbException and so
reaches Degrade(ex.Message) unredacted.
It is unreachable in today's control flow only because the connection string
is static and validated identically at Initialize first — an emergent
property, not an enforced invariant, and a live per-poll leak the moment a
future edit (refresh-on-reinit, a different provider) breaks that assumption.
Make the fallback type-only like the other two sites; the full exception still
reaches the log sink via the exception parameter. The I1 defer + control tests
are unaffected (they assert Degraded, not message text). Pinned by a new test
driving a credential-bearing ArgumentException through HandlePollError;
verified load-bearing (red against Degrade(ex.Message), green after).
Closes the C1 review finding on commit 37f444b9.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Add DriverTypeNames.Sql (+ All) as the shared source of truth, and wire the driver
into the Host: register the factory in DriverFactoryBootstrap.Register via
Driver.Sql.SqlDriverFactoryExtensions.Register(registry, loggerFactory), add the
SqlProbe (= Driver.Sql.SqlDriverProbe) probe via TryAddEnumerable, and add the
Driver.Sql project reference to the Host. Default tier A (SQL client is managed +
cross-platform, so ShouldStub needs no change).
Repoint the interim SqlDriver.DriverTypeName / SqlDriverFactoryExtensions.DriverTypeName
literals at DriverTypeNames.Sql; both still resolve to "Sql", so the AdminUI
TagConfigEditorMap/TagConfigValidator keys and the DriverTypeName-parity test stay
green. The Core guard test discovers factories from its own bin, so it also gains a
Driver.Sql project reference — that is the "registered-factory side" that lets
DriverTypeNamesGuardTests' bidirectional-parity check pass (4/4 green).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Review follow-up on the blackhole gate. Two robustness gaps, both bounded to the
disposable dedicated container (never shared infra), fixed:
- If the outer token fired while 'docker pause' was in flight, 'paused' was set
only AFTER the await, so a cancellation there left paused=false while the
container could still complete the pause — the finally then skipped unpause and
leaked a frozen container. Mark paused BEFORE the await, and make the finally's
unpause best-effort (unpausing a never-actually-paused container errors
harmlessly, and a cleanup failure must never mask the real test outcome).
- The pause/unpause shell commands had no wall-clock bound of their own — only the
post-pause read was capped — so a hung SSH handshake would hang CI. Give
RunShellCommandAsync its own 30s hard cap that kills the process and throws
TimeoutException, distinct from an operator's own cancellation.
Offline skip still clean (1 skipped, 9ms, no socket/docker).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
C1: SqlDriver's Initialize/Read failure paths no longer interpolate the ADO.NET
provider's ex.Message into LastError, the thrown message, or host status — only
ex.GetType().Name reaches the operator surface; the full exception goes to the log
sink via the structured logger's exception parameter. The driver is dialect-agnostic
over an arbitrary DbProviderFactory, so it cannot rely on any provider's message
discipline (Microsoft.Data.SqlClient's parser echoes an unrecognised keyword
lower-cased, which a value-based redactor misses).
C1a: replace the vacuous credential test (SQLite's "unable to open" message never
contains the connection string, so it passed regardless) with one that fabricates a
DbException whose own .Message carries a credential token and drives it through the
Initialize liveness-failure path via the injectable factory seam — red against the
pre-fix ex.Message interpolation.
I1: HandlePollError now ignores the DbException class ReadAsync already classified,
so a subscribed-read outage is classified (and logged) once, not twice with the
worse message.
I2: the poll's Healthy verdict routes through a shared SetHealthUnlessFaulted guard
(the one Degrade already used), so a late in-flight poll cannot un-fault a driver a
concurrent ReinitializeAsync just faulted.
I3: DiscoverAsync warns when materializing an omitted-type tag as String, the only
operator signal for the declared-vs-published type mismatch on a numeric column.
M1: BuildTagTable wraps the per-entry parse so a stray non-JsonException throw skips
the tag instead of stranding health at Initializing (it runs before Initialize's
try/catch). M2 left as a documented TODO to avoid touching SqlPollReader.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SqlTagConfigModel + SqlRowSelectorModel mirror SqlEquipmentTagParser's
accept/reject boundary byte-for-byte on the fields they own: model/type
serialize as NAME strings (never numbers), KeyValue requires
table+keyColumn+keyValue+valueColumn, WideRow requires table+columnName+a
selector (where-pair OR topByTimestamp), Query is rejected, and unknown keys
(top-level and nested rowSelector) survive load->save. Registered in
TagConfigEditorMap + TagConfigValidator keyed off SqlDriver.DriverTypeName
(DriverTypeNames.Sql is deferred to Task 11). A minimal placeholder
SqlTagConfigEditor.razor lands the map entry now; Task 20 fleshes out the UI.
The load-bearing test rounds editor output back through
SqlEquipmentTagParser.TryParse (editor-output <=> parser-input agreement).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Its doc said it pinned "the real provider's cancellation path", but the
token is cancelled before ReadAsync so the OCE is raised at the reader's
SemaphoreSlim.WaitAsync gate, before any SqlConnection opens — it never
exercises Microsoft.Data.SqlClient's in-flight command cancellation.
Softened (option (a)) to state accurately what it proves: an already-
cancelled token propagates as OCE and is never swallowed into a Bad
snapshot or an unreachable-database verdict. The in-flight/deadline path
is covered by SqlBlackholeTimeoutTests.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Adds the frozen-peer / BadTimeout gate for the Sql driver — the single
highest-value integration test. Mirrors the S7 R2-01 blackhole gate:
docker pause a DEDICATED mssql mid-poll, assert the next read surfaces
BadTimeout within the client-side operationTimeout (≈3s) and well below
the server-side CommandTimeout backstop (30s), the driver degrades
(Degraded + host Stopped), and docker unpause recovers to Healthy/Running.
- Docker/docker-compose.yml: disposable `otopcua-sql-blackhole` mssql on
:14333 (never the shared :14330 ConfigDb server) + one-shot seed.
- Docker/seed.sql: the two sample tables.
- SqlBlackholeTimeoutTests.cs: env-gated (SQL_BLACKHOLE_ENDPOINT); pauses
ONLY the hard-coded container name; skips loudly if the endpoint is the
shared port 14330; bounds its own wait so a wedged impl fails, not hangs.
Offline: clean skip (no socket, no docker shell-out).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Locks the driver's injection guarantee against the SQLite fixture. An
authored VALUE ('; DROP TABLE TagValues; --) binds as a DbParameter and can
only ever be a key that matches no row (BadNoData); the seed table survives.
A hostile IDENTIFIER in table/column position is dialect-quoted into a
single nonexistent identifier — inert — and the payload never executes.
Scope, stated plainly: design §8.1 also specifies a catalog gate (validate
an authored identifier against INFORMATION_SCHEMA, reject an unknown one as
BadNodeIdUnknown). That gate does NOT exist in the driver yet and no task
here builds it, so a hostile identifier is not rejected up front — it is
quoted, the query fails after the connection opened, and the tag Bad-codes
as a query failure (BadCommunicationError), not BadNodeIdUnknown. These
tests assert what the code actually guarantees — the payload is inert and
the table intact — rather than a catalog gate that isn't there. The gate is
a tracked follow-up.
No implementation change: the reader already binds correctly (Task 7); this
suite pins it. Falsifiability-checked — forcing a real DROP before the
row-count assertion turns it red, so "table survives" is load-bearing.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Register SqlDriverBrowser as an IDriverBrowser beside the OpcUaClient/Galaxy
lines, project-reference Driver.Sql.Browser, and add SqlAddressPickerBody.razor:
a DriverBrowseTree schema/table/column picker (DriverOperator-gated) with a
column attribute side-panel, manual-entry model/selector fields retained, that
composes the per-tag TagConfig blob (KeyValue / WideRow) matched to
SqlEquipmentTagParser. Pasted ad-hoc connection strings are session-only and
never persisted into the composed blob or driver config.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The AdminUI "Test Connect" probe for the Sql driver: open a connection, run
the dialect's LivenessSql (SELECT 1) under a linked-CTS deadline, return
green with latency or red with a reason. Implements IDriverProbe; never
throws (malformed JSON, missing connectionStringRef, unprovisioned
connection string, a provider open failure, timeout, cancellation all
become red results).
Parses the SAME factory DTO with the SAME JsonStringEnumConverter as
SqlDriverFactoryExtensions (R2-11 factory parity, mirroring
ModbusDriverProbe) and resolves connectionStringRef the same way, so a
config that Test-Connects is the config that Deploys.
Credential hygiene: the resolved connection string never reaches the result
message. A provider exception can embed the data source in its OWN message
(the real SqlException shape), so the catch-all names the exception TYPE
only, never ex.Message. The regression test's fake connection embeds the
connection string in its thrown message specifically so surfacing ex.Message
would leak it — verified load-bearing by breaking the guard and watching it
go red.
ForTest injects factory+dialect for the offline SQLite fixture path.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SqlDriverFactoryExtensions turns a deployed DriverConfig blob into a live
SqlDriver, and SqlConnectionStringResolver resolves the authored
connectionStringRef NAME from Sql__ConnectionStrings__<ref> so credentials
never ride in a config blob (design §8.2).
Three behaviours worth naming:
- String-enum guard. JsonOptions carries JsonStringEnumConverter +
camelCase, so `provider` parses whether authored as a name or an ordinal
and always round-trips as the NAME — the systemic AdminUI defect where a
page serialised an enum numerically against a string-typed DTO.
- Config validation lands here because nothing below does it.
operationTimeout must be STRICTLY greater than commandTimeout (design
§8.3); the reader and the driver stay deliberately usable with the pair
inverted so the frozen-database tests can prove the client-side bound
fires. Non-positive timeouts / poll interval and maxConcurrentGroups < 1
are rejected too.
- Credential hygiene. The resolved connection string reaches the provider
and nothing else: messages name the ref, the environment variable, or
SqlDriver.Endpoint's credential-free server/database rendering. Both a
log-leak and an exception-leak test cover it.
DTO changes:
- Adds RawTags (List<RawTagEntry>), following the Modbus precedent — the
deploy artifact delivers a driver's tags this way and the DTO had no way
to receive them, so an authored Sql tag could never reach the driver.
- Deletes SqlProbeDto + the `probe` key. It had no consumer: SqlDriver was
specified without a background probe loop, and deliberately so — its
IHostConnectivityProbe state is a by-product of the Initialize liveness
check and of every poll, i.e. a statement about traffic that actually
happened rather than a synthetic ping. On-demand connectivity is Task
10's SqlDriverProbe. Shipping a config key that silently does nothing is
worse than not shipping it; UnmappedMemberHandling.Skip means a blob that
still carries `probe` keeps parsing.
allowWrites stays inert (SqlDriver implements no write capability) but an
authored `true` now WARNS rather than passing silently — the flag cannot do
harm, an operator who believes writes are enabled can.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Opens one transient DbConnection from a form-supplied driver-config blob and
hands ownership to SqlBrowseSession, which closes it on disposal. A database is
named either by connectionStringRef — resolved in the AdminUI process from
Sql__ConnectionStrings__<ref>, with an unresolvable ref naming the exact missing
variable — or by a pasted, session-only literal. The literal wins and the ref is
then not read; it cannot arrive from a persisted blob (SqlDriverConfigDto has no
such property), so its presence proves an operator typed it now.
Credential hygiene is the point of the type: no cached config field, nothing
persisted, and no connection text in any log line or exception. Live-probed:
Microsoft.Data.SqlClient and Microsoft.Data.Sqlite keep connection-string values
out of SqlException/SqliteException, but their connection-string PARSER echoes an
unrecognised keyword verbatim — and an unquoted ';' inside a password splits, so
the tail of the password is reported as a keyword (Password=Sup3r;SecretTail =>
"Keyword not supported: 'secrettail;connect timeout'."). The parser's message is
therefore never surfaced; every other failure additionally passes through a
substring redactor that drops the inner exception when it fires.
DriverType comes from SqlDriver.DriverTypeName, the driver's interim local
constant — DriverTypeNames.Sql is added by the driver-factory task.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Three review findings against SqlPollReader (967e5140).
1. WideRow's where-pair form emits no ORDER BY and no row limit, so a
selector that is not actually unique made the reader publish an
arbitrary, storage-order-dependent row — silently, unlike IndexByKey's
duplicate-key warning. Row selection moves out of MapMember into a new
SelectWideRow, which is called once per group and emits the same
rate-limited contract warning (naming table, selector and row count).
The row-limit half of the suggested fix was deliberately NOT taken: a
TOP 1 with no ORDER BY is not deterministic either, and it would
destroy the Rows.Count > 1 evidence the warning depends on, turning a
loud misconfiguration into a permanently silent one. Rationale is in
SelectWideRow's docs. No SQL changed, so no planner golden string moved.
2. The "a frozen database can never accumulate more than
maxConcurrentGroups connections" claim was asserted in the docs and
untested. ReadAsync_aTimedOutGroupKeepsItsConcurrencySlotUntilTheQuery-
TrulyFinishes wedges a group behind an EXCLUSIVE transaction, times it
out, and proves the slot is still held (a second poll on a cap of 1
times out on the gate without ever reaching the factory) and is handed
back only once the abandoned query truly finishes. Moving the release
from the work to the waiter fails this test and no other.
3. Task.Run thread-pool starvation: documented, not changed.
Microsoft.Data.SqlClient's async path parks no pool thread on a frozen
server, so the driver cannot starve itself; LongRunning would cost a
dedicated OS thread per group per poll forever to insure against a
provider this driver does not ship. RunGroupAsync now records the
decision and what a BadTimeout does and does not mean, for the
blackhole gate.
Also: the timeout warning now names the group's table, so a BadTimeout
storm identifies which source is frozen.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Walks schemas -> tables/views -> columns via ISqlDialect's catalog SQL, with
@schema/@table bound as parameters at every level. Column leaves carry the
dialect-mapped DriverDataType in the attribute side-panel (ViewOnly, read-only
v1).
The NodeId encoding deliberately departs from the design sketch's literal
`schema.table|column`: SQL Server permits `.` and `|` inside a quoted
identifier, so that form mis-parses (main.a.b|c reads equally as schema
`main`+table `a.b` and schema `main.a`+table `b`) and silently binds an
operator's tag to the wrong column. SqlBrowseNodeId encodes
`<kind>:<part>[|<part>...]` with `\`/`|` escaped and the kind prefix carrying
the arity; it is public because the picker body decodes it back.
The session owns the connection it is handed and closes it on dispose -- the
registry-held session is the only lifetime hook, so a non-owning session would
leak one pooled connection per reaped picker. Per-call work stays bounded by
the AdminUI's existing 20s linked CTS (BrowserSessionService.PerCallTimeout);
no second deadline is invented here.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
SqlDriver implements IDriver / ITagDiscovery / IReadable / ISubscribable /
IHostConnectivityProbe / IAsyncDisposable over the landed SqlPollReader,
mirroring ModbusDriver. IWritable is deliberately absent: v1 is read-only
structurally, and every discovered variable is SecurityClass=ViewOnly.
The shell classifies poll outcomes because nothing below it does. The reader
honours IReadable literally — it throws only when the database is unreachable
and Bad-codes everything else — so a frozen database returns all-BadTimeout
snapshots through a perfectly successful PollGroupEngine tick. Without
ObservePollOutcome the driver would report Healthy while every value was Bad.
Connection-class codes (BadTimeout / BadCommunicationError) degrade health and
report the host Stopped; authoring-class codes (unresolvable RawPath, absent
row, type mismatch) change nothing, so a tag typo never reports the database
down. It deliberately does NOT synthesise an exception to earn engine backoff:
the engine's exception path publishes nothing, which would cost clients the
Bad quality the reader went out of its way to produce.
Initialize builds the authored RawPath table first (pure, cannot fail; a
malformed TagConfig is logged and skipped) then verifies liveness over one
open-use-dispose connection bounded by wall clock as well as by token (the
R2-01 lesson) — failure records Faulted and rethrows so DriverInstanceActor
retries. The connection string is never logged: a credential-free
server/database Endpoint is the only rendering that reaches a log, LastError,
or the host status.
DriverTypeNames.Sql is NOT added here — DriverTypeNamesGuardTests asserts
bidirectional parity with registered factories, so the constant must land with
the factory (Task 11). SqlDriver.DriverTypeName carries the string until then.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Code-review Minor: the record typed ParameterNames/Parameters/Members/
SelectedColumns as IReadOnlyList<T> but was handed the planner's live List<T>
instances. SqlQueryPlan documents itself as safe to hold for plan caching, so
an aliased list is a real hazard once the reader starts reusing plans across
polls: IReadOnlyList<T> is downcastable, and one mutation would corrupt every
subsequent poll served by that plan.
Copying at the record boundary fixes it for every call site at once rather
than relying on each planner branch remembering to call AsReadOnly.
Pinned by a test that mutates the caller's lists after construction; verified
load-bearing (reverting the record turns it red).
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Executes a poll pass: resolve refs -> SqlGroupPlanner.Plan -> one command per
group -> slice the result set back to per-tag DataValueSnapshots, positionally
aligned with the caller's reference list (design §3.2).
The frozen-peer contract (design §8.3, the R2-01 S7 lesson) is the core of it.
CommandTimeout is only the server-side backstop; the client-side bound is a
linked CancelAfter PLUS Task.WaitAsync, because a linked token bounds only a
provider that honours it and ADO.NET providers vary. The whole per-group
operation — waiting for a concurrency slot, OpenAsync, and the query — runs off
one operationTimeout budget, so ReadAsync returns on time regardless of what the
database is doing. A breach Bad-codes that group (BadTimeout); caller
cancellation propagates instead, since nobody consumes a torn-down poll.
Also: absent row (BadNoData) stays distinct from a NULL cell (Uncertain, or Bad
under nullIsBad); duplicate plan members are all fed (two tags on one keyValue
bind one parameter but stay two members); the concurrency slot is released by the
work, not the waiter, so a frozen database can never hold more than
maxConcurrentGroups connections; the whole call throws only when the connection
itself cannot open, which is what earns PollGroupEngine's backoff.
SqlStatusCodes is driver-local, matching every sibling driver's own table — there
is no shared helper in Core.Abstractions and drivers do not reference the OPC UA
SDK. Values were read off Opc.Ua.StatusCodes rather than copied from a sibling,
because two of those tables carry transcription errors.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Three findings from the code review of the dialect seam:
- QuoteIdentifier used char.IsControl, which only covers Unicode category Cc.
Bidi overrides, zero-width spaces, soft hyphen and BOM are category Cf and
passed through untouched. They cannot escape the brackets, so this is not an
injection bypass — but the method rejects control characters precisely to
protect the integrity of logged/audited statements, and Cf characters spoof
rendered text while comparing byte-different from the real catalog name
(Trojan Source, CVE-2021-42574). Same rule, same rationale, wider category.
- The XML docs on both files asserted that identifiers 'are sourced only from
catalog-validated (INFORMATION_SCHEMA) names' and that rejection is 'a
backstop, not the primary defence'. Neither is true yet: design §8.1 does
specify that gate, but nothing implements it and no task in the plan
schedules one, so an authored TagConfig table/column reaches QuoteIdentifier
unfiltered. The docs now say so, because under-scrutinising this method on
the strength of a filter that does not exist is exactly the failure mode.
- The control-character test only pinned NUL, so a regression to a
Contains('\0') check would still have passed. Pinned the whole Cc category
plus the new Cf rule; verified load-bearing by deleting the guard and
observing exactly the 5 new cases go red.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
The dialect owns the two things ADO.NET's System.Data.Common base types
cannot abstract: identifier quoting and the metadata-catalog SQL. It is
the driver's SQL-injection boundary — values always bind as DbParameters,
identifiers cannot, so the few that reach a command text are catalog-
sourced and pass through QuoteIdentifier.
QuoteIdentifier brackets one identifier part and doubles embedded ] (the
only metacharacter that can terminate a bracketed identifier early);
rejects null/empty/whitespace, >128 chars (T-SQL sysname ceiling), and any
control character (incl. NUL) as ArgumentException, without echoing the
untrusted value into the message. MapColumnType folds the design §3.7
families case-insensitively and never throws — an unrecognised family
falls back to String so a browse over an exotic column still renders;
timestamp/rowversion and time are deliberately NOT mapped to DateTime.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty