Glossary

Term	Meaning
Dialect	The SQL grammar, types, functions and capabilities the analyser understands.
Driver	The database client used by generated code or the migration CLI.
Emitter	The component that writes Go for a particular driver API.
Migration	A versioned schema change, normally with up and down SQL.
Catalogue	Seagull's in-memory description of tables, columns, views, types and functions.
Query	One named SQL statement with an `sgl.query` header.
Directive	A SQL comment carrying generation or migration metadata.
Diagnostic	A located message with severity and a stable Q-code.
Preset	An embedder's vocabulary and type choices for generation.
Model	The struct `models.go` declares for a table, with a field per column.
Row struct	The struct a query's rows are read into: `<Name>Row` by default, or a model or a shared row type a `model:` or `row:` keyword names.
Type slot	The Go type one category of SQL values maps to, such as decimals or intervals, set under `go.types` or in a preset.
Type override	A Go type, element nullability or struct tags chosen for one SQL type or one column, in `sgl.yaml` or a `sgl.column` directive.

A schema source builds a catalogue without migration replay. Introspection is a schema source that reads a database. A generated header identifies output that the writer owns and may prune. A dirty migration is an interrupted run whose recorded progress needs evaluation before resuming.