Class NoRowsResultSetImpl

java.lang.Object
org.apache.derby.impl.sql.execute.NoRowsResultSetImpl
All Implemented Interfaces:
ResultSet
Direct Known Subclasses:
CallStatementResultSet, DMLWriteResultSet, MergeResultSet, MiscResultSet
abstract class NoRowsResultSetImpl extends Object implements ResultSet
Abstract ResultSet for implementations that do not return rows. Examples are DDL statements, CALL statements and DML.

An implementation must provide a ResultSet.open() method that performs the required action.

ResultSet.returnsRows() returns false and any method that fetches a row will throw an exception.

  • Field Details

    • activation

      final Activation activation

    • subqueryTrackingArray

      private NoPutResultSet[] subqueryTrackingArray

    • statisticsTimingOn

      private final boolean statisticsTimingOn

    • isOpen

      private boolean isOpen
      True if the result set has been opened, and not yet closed.

    • lcc

      final LanguageConnectionContext lcc

    • beginTime

      protected long beginTime

    • endTime

      protected long endTime

    • beginExecutionTime

      protected long beginExecutionTime

    • endExecutionTime

      protected long endExecutionTime

    • firstColumn

      private int firstColumn

    • generatedColumnPositions

      private int[] generatedColumnPositions

    • normalizedGeneratedValues

      private DataValueDescriptor[] normalizedGeneratedValues

  • Constructor Details

    • NoRowsResultSetImpl

      NoRowsResultSetImpl(Activation activation)

  • Method Details

    • setup

      void setup() throws StandardException
      Set up the result set for use. Should always be called from open().
      Throws:
      StandardException - thrown on error

    • returnsRows

      public final boolean returnsRows()
      Returns FALSE
      Specified by:
      returnsRows in interface ResultSet
      Returns:
      TRUE if the statement returns rows, FALSE if not.

    • modifiedRowCount

      public long modifiedRowCount()
      Returns zero.
      Specified by:
      modifiedRowCount in interface ResultSet
      Returns:
      The number of rows affect by the statement, so far.

    • getResultDescription

      public ResultDescription getResultDescription()
      Returns null.
      Specified by:
      getResultDescription in interface ResultSet
      Returns:
      A ResultDescription describing the results of the statement.

    • getActivation

      public final Activation getActivation()
      Specified by:
      getActivation in interface ResultSet

    • getAbsoluteRow

      public final ExecRow getAbsoluteRow(int row) throws StandardException
      Returns the row at the absolute position from the query, and returns NULL when there is no such position. (Negative position means from the end of the result set.) Moving the cursor to an invalid position leaves the cursor positioned either before the first row (negative position) or after the last row (positive position). NOTE: An exception will be thrown on 0.
      Specified by:
      getAbsoluteRow in interface ResultSet
      Parameters:
      row - The position.
      Returns:
      The row at the absolute position, or NULL if no such position.
      Throws:
      StandardException - Thrown on failure
      See Also:

    • getRelativeRow

      public final ExecRow getRelativeRow(int row) throws StandardException
      Returns the row at the relative position from the current cursor position, and returns NULL when there is no such position. (Negative position means toward the beginning of the result set.) Moving the cursor to an invalid position leaves the cursor positioned either before the first row (negative position) or after the last row (positive position). NOTE: 0 is valid. NOTE: An exception is thrown if the cursor is not currently positioned on a row.
      Specified by:
      getRelativeRow in interface ResultSet
      Parameters:
      row - The position.
      Returns:
      The row at the relative position, or NULL if no such position.
      Throws:
      StandardException - Thrown on failure
      See Also:

    • setBeforeFirstRow

      public final ExecRow setBeforeFirstRow() throws StandardException
      Sets the current position to before the first row and returns NULL because there is no current row.
      Specified by:
      setBeforeFirstRow in interface ResultSet
      Returns:
      NULL.
      Throws:
      StandardException - Thrown on failure
      See Also:

    • getFirstRow

      public final ExecRow getFirstRow() throws StandardException
      Returns the first row from the query, and returns NULL when there are no rows.
      Specified by:
      getFirstRow in interface ResultSet
      Returns:
      The first row, or NULL if no rows.
      Throws:
      StandardException - Thrown on failure
      See Also:

    • getNextRow

      public final ExecRow getNextRow() throws StandardException
      No rows to return, so throw an exception.
      Specified by:
      getNextRow in interface ResultSet
      Returns:
      The next row, or NULL if no more rows.
      Throws:
      StandardException - Always throws a StandardException to indicate that this method is not intended to be used.
      See Also:

    • getPreviousRow

      public final ExecRow getPreviousRow() throws StandardException
      Returns the previous row from the query, and returns NULL when there are no more previous rows.
      Specified by:
      getPreviousRow in interface ResultSet
      Returns:
      The previous row, or NULL if no more previous rows.
      Throws:
      StandardException - Thrown on failure
      See Also:

    • getLastRow

      public final ExecRow getLastRow() throws StandardException
      Returns the last row from the query, and returns NULL when there are no rows.
      Specified by:
      getLastRow in interface ResultSet
      Returns:
      The last row, or NULL if no rows.
      Throws:
      StandardException - Thrown on failure
      See Also:

    • setAfterLastRow

      public final ExecRow setAfterLastRow() throws StandardException
      Sets the current position to after the last row and returns NULL because there is no current row.
      Specified by:
      setAfterLastRow in interface ResultSet
      Returns:
      NULL.
      Throws:
      StandardException - Thrown on failure
      See Also:

    • clearCurrentRow

      public final void clearCurrentRow()
      Clear the current row. This is done after a commit on holdable result sets. This is a no-op on result set which do not provide rows.
      Specified by:
      clearCurrentRow in interface ResultSet

    • checkRowPosition

      public final boolean checkRowPosition(int isType)
      Determine if the cursor is before the first row in the result set.
      Specified by:
      checkRowPosition in interface ResultSet
      Returns:
      true if before the first row, false otherwise. Returns false when the result set contains no rows.

    • getRowNumber

      public final int getRowNumber()
      Returns the row number of the current row. Row numbers start from 1 and go to 'n'. Corresponds to row numbering used to position current row in the result set (as per JDBC).
      Specified by:
      getRowNumber in interface ResultSet
      Returns:
      the row number, or 0 if not on a row

    • close

      public void close(boolean underMerge) throws StandardException
      Dump the stat if not already done so. Close all of the open subqueries.
      Parameters:
      underMerge - True if this is part of an action of a MERGE statement.
      Throws:
      StandardException - thrown on error

    • isClosed

      public boolean isClosed()
      Find out if the ResultSet is closed.
      Specified by:
      isClosed in interface ResultSet
      Returns:
      true if closed, false otherwise

    • finish

      public void finish() throws StandardException
      Description copied from interface: ResultSet
      Tells the system that there will be no more access to any database information via this result set; in particular, no more calls to open(). Will close the result set if it is not already closed.
      Specified by:
      finish in interface ResultSet
      Throws:
      StandardException - on error

    • getExecuteTime

      public long getExecuteTime()
      Get the execution time in milliseconds.
      Specified by:
      getExecuteTime in interface ResultSet
      Returns:
      long The execution time in milliseconds.

    • getBeginExecutionTimestamp

      public Timestamp getBeginExecutionTimestamp()
      Get the Timestamp for the beginning of execution.
      Specified by:
      getBeginExecutionTimestamp in interface ResultSet
      Returns:
      Timestamp The Timestamp for the beginning of execution.

    • getEndExecutionTimestamp

      public Timestamp getEndExecutionTimestamp()
      Get the Timestamp for the end of execution.
      Specified by:
      getEndExecutionTimestamp in interface ResultSet
      Returns:
      Timestamp The Timestamp for the end of execution.

    • getQueryPlanText

      public String getQueryPlanText(int depth)
      RESOLVE - This method will go away once it is overloaded in all subclasses. Return the query plan as a String.
      Parameters:
      depth - Indentation level.
      Returns:
      String The query plan as a String.

    • getTimeSpent

      public long getTimeSpent(int type)
      Return the total amount of time spent in this ResultSet
      Specified by:
      getTimeSpent in interface ResultSet
      Parameters:
      type - CURRENT_RESULTSET_ONLY - time spent only in this ResultSet ENTIRE_RESULTSET_TREE - time spent in this ResultSet and below.
      Returns:
      long The total amount of time spent (in milliseconds).

    • getSubqueryTrackingArray

      public final NoPutResultSet[] getSubqueryTrackingArray(int numSubqueries)
      Description copied from interface: ResultSet
      Get the subquery ResultSet tracking array from the top ResultSet. (Used for tracking open subqueries when closing down on an error.)
      Specified by:
      getSubqueryTrackingArray in interface ResultSet
      Parameters:
      numSubqueries - The size of the array (For allocation on demand.)
      Returns:
      NoPutResultSet[] Array of NoPutResultSets for subqueries.
      See Also:

    • getAutoGeneratedKeysResultset

      public ResultSet getAutoGeneratedKeysResultset()
      Description copied from interface: ResultSet
      ResultSet for rows inserted into the table (contains auto-generated keys columns only)
      Specified by:
      getAutoGeneratedKeysResultset in interface ResultSet
      Returns:
      NoPutResultSet NoPutResultSets for rows inserted into the table.
      See Also:

    • getCursorName

      public String getCursorName()
      Return the cursor name, null in this case.
      Specified by:
      getCursorName in interface ResultSet
      Returns:
      A String with the name of the cursor, if any. Returns NULL if this is not a cursor statement.
      See Also:

    • getCurrentTimeMillis

      protected final long getCurrentTimeMillis()
      Return the current time in milliseconds, if DEBUG and RunTimeStats is on, else return 0. (Only pay price of system call if need to.)
      Returns:
      long Current time in milliseconds.

    • evaluateGenerationClauses

      public void evaluateGenerationClauses(GeneratedMethod generationClauses, Activation activation, NoPutResultSet source, ExecRow newRow, boolean isUpdate) throws StandardException
      Compute the generation clauses on the current row in order to fill in computed columns.
      Parameters:
      generationClauses - the generated method which evaluates generation clauses
      activation - the thread-specific instance of the generated class
      source - the tuple stream driving this INSERT/UPDATE
      newRow - the base row being stuffed
      isUpdate - true if this is an UPDATE. false otherwise.
      Throws:
      StandardException

    • setupGeneratedColumns

      private void setupGeneratedColumns(Activation activation, ValueRow newRow) throws StandardException
      Construct support for normalizing generated columns. This figures out which columns in the target row have generation clauses which need to be run.
      Throws:
      StandardException

    • doesCommit

      public boolean doesCommit()
      Does this ResultSet cause a commit or rollback.
      Returns:
      Whether or not this ResultSet cause a commit or rollback.

    • addWarning

      public void addWarning(SQLWarning w)
      Description copied from interface: ResultSet
      Add a warning to this result set.
      Specified by:
      addWarning in interface ResultSet
      Parameters:
      w - the warning to add

    • getWarnings

      public SQLWarning getWarnings()
      Description copied from interface: ResultSet
      Return the set of warnings generated during the execution of this result set. The warnings are cleared once this call returns.
      Specified by:
      getWarnings in interface ResultSet

    • toXML

      public Element toXML(Element parentNode, String tag) throws Exception
      Description copied from interface: ResultSet

      Produce an xml image of this ResultSet and its descendant ResultSets. Appends an element to the parentNode and returns the appended element.

      Specified by:
      toXML in interface ResultSet
      Parameters:
      parentNode - Node to put content into.
      tag - Element tag for content
      Returns:
      the content as an element with the given tag name
      Throws:
      Exception