Fuaran.DB.Dialect.SqlServer 0.1.0

Fuaran.DB.Dialect.SqlServer

The SQL Server (T-SQL) dialect of the Fuaran.DB provider. It decides how a statement is spelled, which constructs it does not lower, and how a host binds a parameter and decodes a result cell. It opens no connection and references no driver: the host binds SqlServer.parameterValue and hands each result cell, as its driver read it, to SqlServer.decodeCell.

Spelling

• Identifiers are bracketed, a closing bracket doubled: ORD_NOTE]X is [ORD_NOTE]]X].
• Parameters are named markers, @p0, @p1, …; a host declares each with the engine type below.
• Paging is ORDER BY … OFFSET @off ROWS FETCH NEXT … ROWS ONLY, each key preceded by CASE WHEN key IS NULL THEN 1 ELSE 0 END so nulls sort last in either direction. T-SQL refuses a fetch of no rows, so the page also carries WHERE @limit > 0 and its fetch count never falls below one: a page of zero rows is a valid statement that keeps none.
• Booleans. T-SQL has no boolean type: a bit read where a condition is required is spelled (v = 1), and a condition read where a value is required is (CASE WHEN c THEN CAST(1 AS bit) WHEN NOT c THEN CAST(0 AS bit) END), which keeps its third value.

The type map

The exact decimal is decimal(38, 10): a value with more than ten digits after the point is rounded by the engine when it is stored, and a value outside the .NET decimal's range is refused by parameterValue by name. bigint, datetimeoffset, binary and spatial types read as no column type. A timestamp keeps the fractional digits its unit states. datetime2 holds at most seven (100 ns), so a nanosecond timestamp is refused by name (typeRefusal): createTable answers Error naming the column, and a nanosecond parameter is a refused construct. A reported timestamp keeps the unit its precision states, the coarsest that holds its digits (a bare datetime2 is the engine's default of seven). A timestamp value travels at its column's unit: parameterValue binds a DateTime exact to the cell's fraction, and decodeCell writes the engine's value at the column's unit, refusing by name one finer than the unit rather than truncating it.

What it lowers

Functions Abs, Round (ROUND(x, 0), half away from zero, as the reference rounds), Floor, Ceil, Trim (the reference's pinned set: space, tab, carriage return, line feed) and Sqrt (null for a negative argument, as the reference answers, where SQRT would raise). Operators +, -, *, the comparisons, AND and OR. Aggregates Count, CountDistinct, Sum (over int widened to bigint), Mean (AVG over a float cast), Min and Max (over bit through tinyint). Every join kind the provider lowers.

Every refusal it declares

Each places the fold boundary at the step that uses it, and the step runs locally in the reference evaluator. The conformance kit has a fixture reaching each one.

Lower, Upper, Length, Median, StdDev, First, Last, Cast, the exact roundings and the empty list are also outside the provider's own declared subset, which refuses them first.

Every difference it pins

Certification

Fuaran.DB.Conformance runs its fixtures through this dialect and a host's executor and reports each as agreed, differing as pinned or differing unexpectedly. The repository's suite runs it against a server when FUARAN_DB_SQLSERVER holds a connection string, creating and dropping a database for the run, and reports the leg as Pending when it does not.