Package mondrian.spi.impl

Class SnowflakeDialect

    • Method Detail

      • 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

      • quoteStringLiteral

        public void quoteStringLiteral​(StringBuilder buf,
                               String s)
        Description copied from interface: Dialect
        Appends to a buffer a single-quoted SQL string.

        For example, in the default dialect, quoteStringLiteral(buf, "Can't") appends "'Can''t'" to buf.

        Specified by:
        quoteStringLiteral in interface Dialect
        Overrides:
        quoteStringLiteral in class JdbcDialectImpl
        Parameters:
        buf - Buffer to append to
        s - Literal

      • allowsOrderByAlias

        public boolean allowsOrderByAlias()
        Description copied from interface: Dialect
        Returns true if aliases defined in the SELECT clause can be used as expressions in the ORDER BY clause.

        For example, in such a dialect,

        SELECT x, x + y AS z FROM t ORDER BY z
        would be legal.

        MySQL, DB2 and Ingres are examples of dialects where this is true; Access is a dialect where this is false.

        Specified by:
        allowsOrderByAlias in interface Dialect
        Overrides:
        allowsOrderByAlias in class JdbcDialectImpl
        Returns:
        Whether aliases defined in the SELECT clause can be used as expressions in the ORDER BY clause.

      • allowsSelectNotInGroupBy

        public boolean allowsSelectNotInGroupBy()
        Description copied from interface: Dialect
        Returns whether the database currently permits queries to include in the SELECT clause expressions that are not listed in the GROUP BY clause. The SQL standard allows this if the database can deduce that the expression is functionally dependent on columns in the GROUP BY clause.

        For example, SELECT empno, first_name || ' ' || last_name FROM emps GROUP BY empno is valid because empno is the primary key of the emps table, and therefore all columns are dependent on it. For a given value of empno, first_name || ' ' || last_name has a unique value.

        Most databases do not, MySQL is an example of one that does (if the functioality is enabled).

        Specified by:
        allowsSelectNotInGroupBy in interface Dialect
        Overrides:
        allowsSelectNotInGroupBy in class JdbcDialectImpl
        Returns:
        Whether this Dialect allows SELECT clauses to contain columns that are not in the GROUP BY clause

      • 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

      • generateRegularExpression

        public String generateRegularExpression​(String source,
                                        String javaRegex)
        Description copied from interface: Dialect
        Must generate a String representing a regular expression match operation between a string literal and a Java regular expression. The string literal might be a column identifier or some other identifier, but the implementation must presume that it is already escaped and fit for use. The regular expression is not escaped and must be adapted to the proper dialect rules.

        Postgres / Greenplum example:

        generateRegularExpression( "'foodmart'.'customer_name'", "(?i).*oo.*") -> 'foodmart'.'customer_name' ~ "(?i).*oo.*"

        Oracle example:

        generateRegularExpression( "'foodmart'.'customer_name'", ".*oo.*") -> REGEXP_LIKE('foodmart'.'customer_name', ".*oo.*")

        Dialects are allowed to return null if the dialect cannot convert that particular regular expression into something that the database would support.

        Specified by:
        generateRegularExpression in interface Dialect
        Overrides:
        generateRegularExpression in class JdbcDialectImpl
        Parameters:
        source - A String identifying the column to match against.
        javaRegex - A Java regular expression to match against.
        Returns:
        A dialect specific matching operation, or null if the dialect cannot convert that particular regular expression into something that the database would support.