Package mondrian.spi.impl

Class VerticaDialect

  • All Implemented Interfaces:
    Dialect
    public class VerticaDialect
extends JdbcDialectImpl
    Implementation of Dialect for the Vertica database.
    Since:
    Sept 11, 2009
    Author:
    Pedro Alves

    • Constructor Detail

    • Method Detail

      • allowsMultipleCountDistinct

        public boolean allowsMultipleCountDistinct()
        Description copied from interface: Dialect
        Returns whether this Dialect supports more than one distinct aggregation in the same query.

        In Derby 10.1,

        select couunt(distinct x) from t
        is OK, but
        select couunt(distinct x), count(distinct y) from t
        gives "Multiple DISTINCT aggregates are not supported at this time."
        Specified by:
        allowsMultipleCountDistinct in interface Dialect
        Overrides:
        allowsMultipleCountDistinct in class JdbcDialectImpl
        Returns:
        whether this Dialect supports more than one distinct aggregation in the same query

      • allowsCountDistinctWithOtherAggs

        public boolean allowsCountDistinctWithOtherAggs()
        Description copied from interface: Dialect
        Returns whether this Dialect supports distinct aggregations with other aggregations in the same query. This may be enabled for performance reasons (Vertica)
        Specified by:
        allowsCountDistinctWithOtherAggs in interface Dialect
        Overrides:
        allowsCountDistinctWithOtherAggs in class JdbcDialectImpl
        Returns:
        whether this Dialect supports more than one distinct aggregation in the same query

      • generateInline

        public String generateInline​(List<String> columnNames,
                             List<String> columnTypes,
                             List<String[]> valueList)
        Description copied from interface: Dialect
        Generates a SQL statement to represent an inline dataset.

        For example, for Oracle, generates 

         SELECT 1 AS FOO, 'a' AS BAR FROM dual
 UNION ALL
 SELECT 2 AS FOO, 'b' AS BAR FROM dual

        For ANSI SQL, generates: 

         VALUES (1, 'a'), (2, 'b')
        Specified by:
        generateInline in interface Dialect
        Overrides:
        generateInline in class JdbcDialectImpl
        Parameters:
        columnNames - List of column names
        columnTypes - List of column types ("String" or "Numeric")
        valueList - List of rows values
        Returns:
        SQL string

      • getType

        public SqlStatement.Type getType​(ResultSetMetaData metaData,
                                 int columnIndex)
                          throws SQLException
        Description copied from interface: Dialect

        Chooses the most appropriate type for accessing the values of a column in a result set for a dialect.

        Dialect-specific nuances involving type representation should be encapsulated in implementing methods. For example, if a dialect has implicit rules involving scale or precision, they should be handled within this method so the client can simply retrieve the "best fit" SqlStatement.Type for the column.

        Specified by:
        getType in interface Dialect
        Overrides:
        getType in class JdbcDialectImpl
        Parameters:
        metaData - Results set metadata
        columnIndex - Column ordinal (0-based)
        Returns:
        the most appropriate SqlStatement.Type for the column
        Throws:
        SQLException

      • supportsMultiValueInExpr

        public boolean supportsMultiValueInExpr()
        Description copied from interface: Dialect
        Returns true if this dialect supports multi-value IN expressions. E.g., WHERE (col1, col2) IN ((val1a, val2a), (val1b, val2b))
        Specified by:
        supportsMultiValueInExpr in interface Dialect
        Overrides:
        supportsMultiValueInExpr in class JdbcDialectImpl
        Returns:
        true if the dialect supports multi-value IN expressions