Documentation
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Overview ¶
Package compare provides shared SQL fragments for dialect statement compilers.
Index ¶
- func CompileBoolEqual[F ~uint8, T any](w Writer, filter *database.CompareFilter[F], schema database.Schema[F, T]) bool
- func CompileCorrelated[F ~uint8, T any](w Writer, filter *database.CorrelatedFilter[F], schema database.Schema[F, T], ...)
- func CompileNullAware[F ~uint8, T any](w Writer, filter *database.CompareFilter[F], schema database.Schema[F, T], ...)
- func NeedsNullAware[F ~uint8, T any](filter *database.CompareFilter[F], schema database.Schema[F, T]) bool
- func WriteNullsOrder[F ~uint8, T any](w Writer, column database.Column[F], direction database.OrderDirection, ...)
- type Writer
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func CompileBoolEqual ¶
func CompileBoolEqual[F ~uint8, T any](w Writer, filter *database.CompareFilter[F], schema database.Schema[F, T]) bool
CompileBoolEqual compiles a single-term equality against a bool constant as the bare (negated) expression. Planners convert a bare EXISTS / NOT EXISTS into a semi/anti-join but evaluate `EXISTS (...) = $1` per row. Reports whether the filter was handled.
func CompileCorrelated ¶
func CompileCorrelated[F ~uint8, T any]( w Writer, filter *database.CorrelatedFilter[F], schema database.Schema[F, T], writeValue func(Writer, any, database.Column[F]), )
CompileCorrelated compiles a database.CorrelatedFilter by writing the column's computed expression around the bound value: SQLName, the value, then SQLSuffix. Every dialect emits the same shape, so the only per-dialect difference is the schema binding's text and the placeholder writeValue emits.
func CompileNullAware ¶
func CompileNullAware[F ~uint8, T any]( w Writer, filter *database.CompareFilter[F], schema database.Schema[F, T], writeValue func(Writer, any, database.Column[F]), )
CompileNullAware expands compares whose terms bind SQL NULL or cover nullable keyset columns. Requires ASC NULLS FIRST / DESC NULLS LAST: postgres and sqlite state it explicitly in ORDER BY for nullable columns, spanner rejects the clause but guarantees that ordering by default. writeValue emits a bound placeholder (and any dialect cast) for non-nil values.
func NeedsNullAware ¶
func NeedsNullAware[F ~uint8, T any](filter *database.CompareFilter[F], schema database.Schema[F, T]) bool
NeedsNullAware reports whether a compare must use null-safe expansion: any term binds SQL NULL, or a keyset compare touches a nullable column (a non-nil cursor value must still admit NULL rows beyond the cursor).
func WriteNullsOrder ¶
func WriteNullsOrder[F ~uint8, T any](w Writer, column database.Column[F], direction database.OrderDirection, schema database.Schema[F, T])
WriteNullsOrder states the NULL position CompileNullAware assumes: ASC NULLS FIRST / DESC NULLS LAST. Emitted only for nullable columns, because on a NOT NULL column the clause changes nothing semantically but stops postgres from matching the default index order (index scan degrades to a full sort). Spanner rejects the clause and guarantees this ordering by default, so its compiler must not call this.
Source Files