Class Projections.ProjectionEvaluator

  • Enclosing class:
    Projections

    public abstract static class Projections.ProjectionEvaluator
    extends ExpressionVisitors.ExpressionVisitor<Expression>
    A class that projects expressions for a table's data rows into expressions on the table's partition values, for a table's partition spec.

    There are two types of projections: inclusive and strict.

    An inclusive projection guarantees that if an expression matches a row, the projected expression will match the row's partition.

    A strict projection guarantees that if a partition matches a projected expression, then all rows in that partition will match the original expression.

    • Constructor Detail

      • ProjectionEvaluator

        public ProjectionEvaluator()
    • Method Detail

      • project

        public abstract Expression project​(Expression expr)
        Project the given row expression to a partition expression.
        Parameters:
        expr - an expression on data rows
        Returns:
        an expression on partition data (depends on the projection)