Package mondrian.spi.impl

Class HiveDialect

java.lang.Object
mondrian.spi.impl.JdbcDialectImpl
mondrian.spi.impl.HiveDialect
All Implemented Interfaces:
Dialect
Direct Known Subclasses:
ImpalaDialect
public class HiveDialect extends JdbcDialectImpl
Implementation of Dialect for the Hive database.
Since:
Jan 10, 2011
Author:
Hongwei Fu

  • Field Details

  • Constructor Details

  • Method Details

    • deduceIdentifierQuoteString

      protected String deduceIdentifierQuoteString(DatabaseMetaData databaseMetaData)
      Overrides:
      deduceIdentifierQuoteString in class JdbcDialectImpl

    • deduceSupportedResultSetStyles

      protected Set<List<Integer>> deduceSupportedResultSetStyles(DatabaseMetaData databaseMetaData)
      Overrides:
      deduceSupportedResultSetStyles in class JdbcDialectImpl

    • deduceReadOnly

      protected boolean deduceReadOnly(DatabaseMetaData databaseMetaData)
      Overrides:
      deduceReadOnly in class JdbcDialectImpl

    • deduceMaxColumnNameLength

      protected int deduceMaxColumnNameLength(DatabaseMetaData databaseMetaData)
      Overrides:
      deduceMaxColumnNameLength in class JdbcDialectImpl

    • allowsCompoundCountDistinct

      public boolean allowsCompoundCountDistinct()
      Description copied from interface: Dialect
      Returns whether this Dialect allows multiple arguments to the COUNT(DISTINCT ...) aggregate function, for example
      SELECT COUNT(DISTINCT x, y) FROM t
      Specified by:
      allowsCompoundCountDistinct in interface Dialect
      Overrides:
      allowsCompoundCountDistinct in class JdbcDialectImpl
      Returns:
      whether Dialect allows multiple arguments to COUNT DISTINCT
      See Also:

    • requiresAliasForFromQuery

      public boolean requiresAliasForFromQuery()
      Description copied from interface: Dialect
      Returns whether this Dialect requires subqueries in the FROM clause to have an alias.
      Specified by:
      requiresAliasForFromQuery in interface Dialect
      Overrides:
      requiresAliasForFromQuery in class JdbcDialectImpl
      Returns:
      whether dialewct requires subqueries to have an alias
      See Also:

    • requiresOrderByAlias

      public boolean requiresOrderByAlias()
      Description copied from interface: Dialect
      Returns true if this Dialect can include expressions in the ORDER BY clause only by adding an expression to the SELECT clause and using its alias.

      For example, in such a dialect,

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

      MySQL, DB2 and Ingres are examples of such dialects.

      Specified by:
      requiresOrderByAlias in interface Dialect
      Overrides:
      requiresOrderByAlias in class JdbcDialectImpl
      Returns:
      Whether this Dialect can include expressions in the ORDER BY clause only by adding an expression to the SELECT clause and using its alias

    • 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.

    • requiresGroupByAlias

      public boolean requiresGroupByAlias()
      Description copied from interface: Dialect
      Returns true if this Dialect can include expressions in the GROUP BY clause only by adding an expression to the SELECT clause and using its alias.

      For example, in such a dialect,

      SELECT x, x FROM t GROUP BY x
      would be illegal, but
      SELECT x AS a, x AS b FROM t ORDER BY a, b
      would be legal.

      Infobright is the only such dialect.

      Specified by:
      requiresGroupByAlias in interface Dialect
      Overrides:
      requiresGroupByAlias in class JdbcDialectImpl
      Returns:
      Whether this Dialect can include expressions in the GROUP BY clause only by adding an expression to the SELECT clause and using its alias

    • requiresUnionOrderByExprToBeInSelectClause

      public boolean requiresUnionOrderByExprToBeInSelectClause()
      Description copied from interface: Dialect
      Returns true if this dialect allows an expression in the ORDER BY clause of a UNION (or other set operation) query only if it occurs in the SELECT clause.

      For example, SELECT x, y + z FROM t
      UNION ALL
      SELECT x, y + z FROM t
      ORDER BY y + z       is allowed but SELECT x, y, z FROM t
      UNION ALL
      SELECT x, y, z FROM t
      ORDER BY y + z       SELECT x, y, z FROM t ORDER BY y + z is not.

      Access is an example of a dialect with this restriction.

      Specified by:
      requiresUnionOrderByExprToBeInSelectClause in interface Dialect
      Overrides:
      requiresUnionOrderByExprToBeInSelectClause in class JdbcDialectImpl
      Returns:
      whether this dialect allows an expression in the ORDER BY clause of a UNION (or other set operation) query only if it occurs in the SELECT clause

    • requiresUnionOrderByOrdinal

      public boolean requiresUnionOrderByOrdinal()
      Description copied from interface: Dialect
      Returns true if this dialect allows only integers in the ORDER BY clause of a UNION (or other set operation) query.

      For example, SELECT x, y + z FROM t
      UNION ALL
      SELECT x, y + z FROM t
      ORDER BY 1, 2       is allowed but SELECT x, y, z FROM t
      UNION ALL
      SELECT x, y, z FROM t
      ORDER BY x       is not.

      Teradata is an example of a dialect with this restriction.

      Specified by:
      requiresUnionOrderByOrdinal in interface Dialect
      Overrides:
      requiresUnionOrderByOrdinal in class JdbcDialectImpl
      Returns:
      whether this dialect allows only integers in the ORDER BY clause of a UNION (or other set operation) 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

    • quoteDateLiteral

      protected void quoteDateLiteral(StringBuilder buf, String value, Date date)
      Description copied from class: JdbcDialectImpl
      Helper method for JdbcDialectImpl.quoteDateLiteral(StringBuilder, String).
      Overrides:
      quoteDateLiteral in class JdbcDialectImpl
      Parameters:
      buf - Buffer to append to
      value - Value as string
      date - Value as date

    • generateOrderByNulls

      protected String generateOrderByNulls(String expr, boolean ascending, boolean collateNullsLast)
      Description copied from class: JdbcDialectImpl
      Generates SQL to force null values to collate last.

      This default implementation makes use of the ANSI SQL 1999 CASE-WHEN-THEN-ELSE in conjunction with IS NULL syntax. The resulting SQL will look something like this:

      CASE WHEN "expr" IS NULL THEN 0 ELSE 1 END

      You can override this method for a particular database to use something more efficient, like ISNULL().

      ANSI SQL provides the syntax "ASC/DESC NULLS LAST" and "ASC/DESC NULLS FIRST". If your database supports the ANSI syntax, implement this method by calling JdbcDialectImpl.generateOrderByNullsAnsi(java.lang.String, boolean, boolean).

      This method is only called from JdbcDialectImpl.generateOrderItem(String, boolean, boolean, boolean). Some dialects override that method and therefore never call this method.

      Overrides:
      generateOrderByNulls in class JdbcDialectImpl
      Parameters:
      expr - Expression.
      ascending - Whether ascending.
      collateNullsLast - Whether nulls should appear first or last.
      Returns:
      Expression to force null values to collate last or first.

    • allowsAs

      public boolean allowsAs()
      Description copied from interface: Dialect
      Returns whether the SQL dialect allows "AS" in the FROM clause. If so, "SELECT * FROM t AS alias" is a valid query.
      Specified by:
      allowsAs in interface Dialect
      Overrides:
      allowsAs in class JdbcDialectImpl
      Returns:
      whether dialect allows AS in FROM clause

    • allowsJoinOn

      public boolean allowsJoinOn()
      Description copied from interface: Dialect
      Returns whether this dialect supports "ANSI-style JOIN syntax", FROM leftTable JOIN rightTable ON conditon.
      Specified by:
      allowsJoinOn in interface Dialect
      Overrides:
      allowsJoinOn in class JdbcDialectImpl
      Returns:
      Whether this dialect supports FROM-JOIN-ON syntax.

    • quoteTimestampLiteral

      public void quoteTimestampLiteral(StringBuilder buf, String value)
      Description copied from interface: Dialect
      Appends to a buffer a timestamp literal.

      For example, in the default dialect, quoteStringLiteral(buf, "1969-03-17 12:34:56") appends TIMESTAMP '1969-03-17 12:34:56'.

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