Documentation
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Overview ¶
Package dialect names the SQL dialects the module's SQL-emitting packages support, and carries the small helpers every one of them otherwise reimplements: bind-marker rendering, identifier vetting, and DDL statement splitting.
It exists to be a leaf. database/migrate, outbox, and authorization/database all speak the same three dialects, and their migrations subpackages cannot import their parents without closing a cycle through the parents' tests — so before this package, each of the five declared its own Dialect type and tests converted between them. One shared type makes those conversions unrepresentable.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ErrInvalidIdentifier = platformerrors.New("invalid SQL identifier")
ErrInvalidIdentifier indicates a name that ValidIdentifier rejects. Packages wrap it with their own context, so errors.Is works across all of them — including across a package that builds a table's DDL and one that queries it, which is the pair most likely to be checked against each other.
var ErrUnsupported = platformerrors.New("unsupported SQL dialect")
ErrUnsupported indicates a dialect outside the supported set. Packages wrap it with their own context, so errors.Is works across all of them.
Functions ¶
func SplitStatements ¶
SplitStatements strips '--' comments from ddl and splits it into individually executable statements on ';', preserving statement order.
Comments come out before the split, not after. A '--' comment may contain a semicolon — prose routinely does — and splitting first tears such a comment in half, leaving its tail masquerading as SQL at the head of the next statement.
Comment stripping handles whole-line '--' comments and blank lines only, not a '--' appearing after SQL on the same line, nor semicolons inside string literals; the DDL shipped by this module contains neither, and the round-trip tests against real servers are what keep that true.
func ValidIdentifier ¶
ValidIdentifier reports whether s is safe to interpolate into query text as a table name. Table names are interpolated rather than bound, so they are restricted rather than escaped.
Types ¶
type Dialect ¶
type Dialect string
Dialect selects the SQL a package emits. It must match the database provider the emitted SQL runs against.
const ( // Postgres targets PostgreSQL, which numbers its placeholders and supports // SKIP LOCKED. Postgres Dialect = "postgres" // MySQL targets MySQL 8.0+ — the first version with WITH RECURSIVE — which // supports SKIP LOCKED. MySQL Dialect = "mysql" // SQLite targets SQLite, which is single-writer by nature and has no // SKIP LOCKED. SQLite Dialect = "sqlite" )
func (Dialect) Placeholder ¶
Placeholder renders the n-th bind marker (1-indexed). Postgres numbers its placeholders; MySQL and SQLite do not.
func (Dialect) Placeholders ¶
Placeholders renders count bind markers starting at start, joined for use inside an IN clause or a VALUES tuple.
func (Dialect) SupportsSkipLocked ¶
SupportsSkipLocked reports whether the dialect can claim rows with FOR UPDATE SKIP LOCKED, which is what allows more than one competing worker to claim from the same table at once.
Source Files