Function processCollationOnType

pkg/sql/sem/tree/create.go:540–566

(
	name Name, ref ResolvableTypeReference, c ColumnCollation,
)

}

func processCollationOnType(
	name Name, ref ResolvableTypeReference, c ColumnCollation,
) (*types.T, error) {
	// At the moment, only string types can be collated. User defined types
	//  like enums don't support collations, so check this at parse time.
	typ, ok := GetStaticallyKnownType(ref)
	if !ok {
		return nil, pgerror.Newf(pgcode.DatatypeMismatch,
			"COLLATE declaration for non-string-typed column %q", name)
	}
	switch typ.Family() {
	case types.StringFamily:
		return types.MakeCollatedString(typ, string(c)), nil
	case types.CollatedStringFamily:
		return nil, pgerror.Newf(pgcode.Syntax,
			"multiple COLLATE declarations for column %q", name)
	case types.ArrayFamily:
		elemTyp, err := processCollationOnType(name, typ.ArrayContents(), c)
		if err != nil {
			return nil, err
		}
		return types.MakeArray(elemTyp), nil
	default:
		return nil, pgerror.Newf(pgcode.DatatypeMismatch,
			"COLLATE declaration for non-string-typed column %q", name)
	}
}

// NewColumnTableDef constructs a column definition for a CreateTable statement.
func NewColumnTableDef(