dbbase.column_types.WriteOnlyColumn.self_group¶
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WriteOnlyColumn.self_group(against=None)¶ Apply a ‘grouping’ to this
_expression.ClauseElement.This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by
_expression.select()constructs when placed into the FROM clause of another_expression.select(). (Note that subqueries should be normally created using the_expression.Select.alias()method, as many platforms require nested SELECT statements to be named).As expressions are composed together, the application of
self_group()is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression likex OR (y AND z)- AND takes precedence over OR.The base
self_group()method of_expression.ClauseElementjust returns self.