Class IndexRowGenerator

java.lang.Object
org.apache.derby.iapi.sql.dictionary.IndexRowGenerator
All Implemented Interfaces:
Externalizable, Serializable, IndexDescriptor, Formatable, TypedFormat
public class IndexRowGenerator extends Object implements IndexDescriptor, Formatable
This class extends IndexDescriptor for internal use by the DataDictionary.

For a description of how deferrable and non-deferrable constraints are backed differently, including the meaning of the boolean attributes used here, see IndexDescriptor.

See Also:

  • Field Details

  • Constructor Details

    • IndexRowGenerator

      public IndexRowGenerator(String indexType, boolean isUnique, boolean isUniqueWithDuplicateNulls, boolean isUniqueDeferrable, boolean hasDeferrableChecking, int[] baseColumnPositions, boolean[] isAscending, int numberOfOrderedColumns)
      Constructor for an IndexRowGeneratorImpl
      Parameters:
      indexType - The type of index
      isUnique - True means the index is unique
      isUniqueWithDuplicateNulls - means the index is almost unique i.e. unique only for non null keys
      isUniqueDeferrable - True means the index represents a PRIMARY KEY or a UNIQUE NOT NULL constraint which is deferrable.
      hasDeferrableChecking - True if the index is used to back a deferrable constraint
      baseColumnPositions - An array of column positions in the base table. Each index column corresponds to a column position in the base table.
      isAscending - An array of booleans telling asc/desc on each column.
      numberOfOrderedColumns - In the future, it will be possible to store non-ordered columns in an index. These will be useful for covered queries.

    • IndexRowGenerator

      public IndexRowGenerator(IndexDescriptor indexDescriptor)
      Constructor for an IndexRowGeneratorImpl
      Parameters:
      indexDescriptor - An IndexDescriptor to delegate calls to

    • IndexRowGenerator

      public IndexRowGenerator()
      Zero-argument constructor for Formatable interface

  • Method Details

    • getIndexRowTemplate

      public ExecIndexRow getIndexRowTemplate()
      Get a template for the index row, to be used with getIndexRow.
      Returns:
      A row template for the index row.

    • getNullIndexRow

      public ExecIndexRow getNullIndexRow(ColumnDescriptorList columnList, RowLocation rowLocation) throws StandardException
      Get a NULL Index Row for this index. This is useful to create objects that need to be passed to ScanController.
      Parameters:
      columnList - ColumnDescriptors describing the base table.
      rowLocation - empty row location.
      Throws:
      StandardException - thrown on error.

    • getIndexRow

      public void getIndexRow(ExecRow baseRow, RowLocation rowLocation, ExecIndexRow indexRow, FormatableBitSet bitSet) throws StandardException
      Get an index row for this index given a row from the base table and the RowLocation of the base row. This method can be used to get the new index row for inserts, and the old and new index rows for deletes and updates. For updates, the result row has all the old column values followed by all of the new column values, so you must form a row using the new column values to pass to this method to get the new index row.
      Parameters:
      baseRow - A row in the base table
      rowLocation - The RowLocation of the row in the base table
      indexRow - A template for the index row. It must have the correct number of columns.
      bitSet - If non-null, then baseRow is a partial row and the set bits in bitSet represents the column mapping for the partial row to the complete base row. WARNING: ONE based!!!
      Throws:
      StandardException - Thrown on error

    • getColumnCollationIds

      public int[] getColumnCollationIds(ColumnDescriptorList columnList) throws StandardException
      Return an array of collation ids for this table.

      Return an array of collation ids, one for each column in the columnDescriptorList. This is useful for passing collation id info down to store, for instance in createConglomerate() to create the index. This is only expected to get called during ddl, so object allocation is ok.

      Parameters:
      columnList - ColumnDescriptors describing the base table.
      Throws:
      StandardException - Standard exception policy.

    • getIndexDescriptor

      public IndexDescriptor getIndexDescriptor()
      Get the IndexDescriptor that this IndexRowGenerator is based on.

    • isUniqueWithDuplicateNulls

      public boolean isUniqueWithDuplicateNulls()
      Description copied from interface: IndexDescriptor
      Returns true if the index is duplicate keys only for null key parts. This is effective only if isUnique is false.
      Specified by:
      isUniqueWithDuplicateNulls in interface IndexDescriptor
      See Also:

    • hasDeferrableChecking

      public boolean hasDeferrableChecking()
      Description copied from interface: IndexDescriptor
      Returns true if the index is used to support a deferrable constraint.
      Specified by:
      hasDeferrableChecking in interface IndexDescriptor

    • isUniqueDeferrable

      public boolean isUniqueDeferrable()
      Description copied from interface: IndexDescriptor
      The index represents a PRIMARY KEY or a UNIQUE NOT NULL constraint which is deferrable. true implies isUnique() == false and isUniqueWithDuplicateNulls() == false and hasDeferrableChecking() == true.
      Specified by:
      isUniqueDeferrable in interface IndexDescriptor
      Returns:
      true if the index represents such a constraint

    • isUnique

      public boolean isUnique()
      Description copied from interface: IndexDescriptor
      Returns true if the index is unique.
      Specified by:
      isUnique in interface IndexDescriptor
      See Also:

    • baseColumnPositions

      public int[] baseColumnPositions()
      Description copied from interface: IndexDescriptor
      Returns an array of column positions in the base table. Each index column corresponds to a column position in the base table, except the column representing the location of the row in the base table. The returned array holds the column positions in the base table, so, if entry 2 is the number 4, the second column in the index is the fourth column in the table.
      Specified by:
      baseColumnPositions in interface IndexDescriptor
      See Also:

    • getKeyColumnPosition

      public int getKeyColumnPosition(int heapColumnPosition)
      Description copied from interface: IndexDescriptor
      Returns the postion of a column.

      Returns the position of a column within the key (1-based). 0 means that the column is not in the key. Same as the above method, but it uses int instead of Integer.

      Specified by:
      getKeyColumnPosition in interface IndexDescriptor
      See Also:

    • numberOfOrderedColumns

      public int numberOfOrderedColumns()
      Description copied from interface: IndexDescriptor
      Returns the number of ordered columns.

      In the future, it will be possible to store non-ordered columns in an index. These will be useful for covered queries. The ordered columns will be at the beginning of the index row, and they will be followed by the non-ordered columns. For now, all columns in an index must be ordered.

      Specified by:
      numberOfOrderedColumns in interface IndexDescriptor
      See Also:

    • indexType

      public String indexType()
      Description copied from interface: IndexDescriptor
      Returns the type of the index. For now, we only support B-Trees, so the value "BTREE" is returned.
      Specified by:
      indexType in interface IndexDescriptor
      See Also:

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • isAscending

      public boolean isAscending(Integer keyColumnPosition)
      Description copied from interface: IndexDescriptor
      Returns true if the specified column is ascending in the index (1-based).
      Specified by:
      isAscending in interface IndexDescriptor
      See Also:

    • isDescending

      public boolean isDescending(Integer keyColumnPosition)
      Description copied from interface: IndexDescriptor
      Returns true if the specified column is descending in the index (1-based). In the current release, only ascending columns are supported.
      Specified by:
      isDescending in interface IndexDescriptor
      See Also:

    • isAscending

      public boolean[] isAscending()
      Description copied from interface: IndexDescriptor
      Returns array of boolean telling asc/desc info for each index key column for convenience of using together with baseColumnPositions method. Both methods return an array with subscript starting from 0.
      Specified by:
      isAscending in interface IndexDescriptor
      See Also:

    • setBaseColumnPositions

      public void setBaseColumnPositions(int[] baseColumnPositions)
      Description copied from interface: IndexDescriptor
      set the baseColumnPositions field of the index descriptor. This is for updating the field in operations such as "alter table drop column" where baseColumnPositions is changed.
      Specified by:
      setBaseColumnPositions in interface IndexDescriptor
      See Also:

    • setIsAscending

      public void setIsAscending(boolean[] isAscending)
      Description copied from interface: IndexDescriptor
      set the isAscending field of the index descriptor. This is for updating the field in operations such as "alter table drop column" where isAscending is changed.
      Specified by:
      setIsAscending in interface IndexDescriptor
      See Also:

    • setNumberOfOrderedColumns

      public void setNumberOfOrderedColumns(int numberOfOrderedColumns)
      Description copied from interface: IndexDescriptor
      set the numberOfOrderedColumns field of the index descriptor. This is for updating the field in operations such as "alter table drop column" where numberOfOrderedColumns is changed.
      Specified by:
      setNumberOfOrderedColumns in interface IndexDescriptor
      See Also:

    • equals

      public boolean equals(Object other)
      Test for value equality
      Overrides:
      equals in class Object
      Parameters:
      other - The other indexrowgenerator to compare this one with
      Returns:
      true if this indexrowgenerator has the same value as other

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object
      See Also:

    • getExecutionFactory

      private ExecutionFactory getExecutionFactory()

    • readExternal

      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
      Specified by:
      readExternal in interface Externalizable
      Throws:
      IOException - Thrown on read error
      ClassNotFoundException - Thrown on read error
      See Also:

    • writeExternal

      public void writeExternal(ObjectOutput out) throws IOException
      Specified by:
      writeExternal in interface Externalizable
      Throws:
      IOException - Thrown on write error

    • getTypeFormatId

      public int getTypeFormatId()
      Description copied from interface: TypedFormat
      Get a universally unique identifier for the type of this object.
      Specified by:
      getTypeFormatId in interface TypedFormat
      Returns:
      The identifier. (A UUID stuffed in an array of 16 bytes).

    • getContext

      private static Context getContext(String contextID)
      Privileged lookup of a Context. Must be private so that user code can't call this entry point.