Package org.apache.derby.catalog.types
Class IndexDescriptorImpl
java.lang.Object
org.apache.derby.catalog.types.IndexDescriptorImpl
- All Implemented Interfaces:
Externalizable
,Serializable
,IndexDescriptor
,Formatable
,TypedFormat
See also
IndexRowGenerator
.
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:
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate int[]
private boolean
The index represents a constraint which is deferrable.private String
private boolean[]
private boolean
This class implements Formatable.private boolean
The index represents a PRIMARY KEY or a UNIQUE NOT NULL constraint which is deferrable.private boolean
private int
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Constructor Summary
ConstructorsConstructorDescriptionZero-argument constructor for Formatable interfaceIndexDescriptorImpl
(String indexType, boolean isUnique, boolean isUniqueWithDuplicateNulls, boolean isUniqueDeferrable, boolean hasDeferrableChecking, int[] baseColumnPositions, boolean[] isAscending, int numberOfOrderedColumns) Constructor for an IndexDescriptorImpl -
Method Summary
Modifier and TypeMethodDescriptionint[]
Returns an array of column positions in the base table.boolean
Test for value equalityint
getKeyColumnPosition
(int heapColumnPosition) Returns the postion of a column.int
Get a universally unique identifier for the type of this object.boolean
Returns true if the index is used to support a deferrable constraint.int
hashCode()
Returns the type of the index.boolean[]
Returns array of boolean telling asc/desc info for each index key column for convenience of using together with baseColumnPositions method.boolean
isAscending
(Integer keyColumnPosition) Returns true if the specified column is ascending in the index (1-based).boolean
isDescending
(Integer keyColumnPosition) Returns true if the specified column is descending in the index (1-based).boolean
isUnique()
Returns true if the index is unique.boolean
The index represents a PRIMARY KEY or a UNIQUE NOT NULL constraint which is deferrable.boolean
Returns true if the index is duplicate keys only for null key parts.int
Returns the number of ordered columns.void
void
setBaseColumnPositions
(int[] baseColumnPositions) set the baseColumnPositions field of the index descriptor.void
setIsAscending
(boolean[] isAscending) set the isAscending field of the index descriptor.void
setNumberOfOrderedColumns
(int numberOfOrderedColumns) set the numberOfOrderedColumns field of the index descriptor.toString()
void
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Field Details
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isUnique
private boolean isUniqueThis class implements Formatable. That means that it can write itself to and from a formatted stream. If you add more fields to this class, make sure that you also write/read them with the writeExternal()/readExternal() methods. If, in between releases, you add more fields to this class, then you should bump the version number emitted by the getTypeFormatId() method. -
baseColumnPositions
private int[] baseColumnPositions -
isAscending
private boolean[] isAscending -
numberOfOrderedColumns
private int numberOfOrderedColumns -
indexType
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isUniqueWithDuplicateNulls
private boolean isUniqueWithDuplicateNulls -
isUniqueDeferrable
private boolean isUniqueDeferrableThe index represents a PRIMARY KEY or a UNIQUE NOT NULL constraint which is deferrable.true
impliesisUnique == false
andisUniqueWithDuplicateNulls == false
andhasDeferrableChecking == true
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hasDeferrableChecking
private boolean hasDeferrableCheckingThe index represents a constraint which is deferrable.
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Constructor Details
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IndexDescriptorImpl
public IndexDescriptorImpl(String indexType, boolean isUnique, boolean isUniqueWithDuplicateNulls, boolean isUniqueDeferrable, boolean hasDeferrableChecking, int[] baseColumnPositions, boolean[] isAscending, int numberOfOrderedColumns) Constructor for an IndexDescriptorImpl- Parameters:
indexType
- The type of indexisUnique
- True means the index is uniqueisUniqueWithDuplicateNulls
- True means the index will be unique for non null values but duplicate nulls will be allowed. This parameter has no effect if the isUnique is true. If isUnique is false and isUniqueWithDuplicateNulls is set to true the index will allow duplicate nulls but for non null keys will act like a unique index.isUniqueDeferrable
- True means the index represents a PRIMARY KEY or a UNIQUE NOT NULL constraint which is deferrable.hasDeferrableChecking
- True if this index supports 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.
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IndexDescriptorImpl
public IndexDescriptorImpl()Zero-argument constructor for Formatable interface
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Method Details
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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 interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
- Returns:
true
is the index supports a deferrable constraint
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isUniqueDeferrable
public boolean isUniqueDeferrable()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 interfaceIndexDescriptor
- Returns:
true
is the index supports such a constraint
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isUnique
public boolean isUnique()Description copied from interface:IndexDescriptor
Returns true if the index is unique.- Specified by:
isUnique
in interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
- See Also:
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isAscending
Description copied from interface:IndexDescriptor
Returns true if the specified column is ascending in the index (1-based).- Specified by:
isAscending
in interfaceIndexDescriptor
- See Also:
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isDescending
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 interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
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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 interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
- See Also:
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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 interfaceIndexDescriptor
- See Also:
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toString
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readExternal
- Specified by:
readExternal
in interfaceExternalizable
- Throws:
IOException
- Thrown on read errorClassNotFoundException
- See Also:
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writeExternal
- Specified by:
writeExternal
in interfaceExternalizable
- Throws:
IOException
- Thrown on write error- See Also:
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getTypeFormatId
public int getTypeFormatId()Description copied from interface:TypedFormat
Get a universally unique identifier for the type of this object.- Specified by:
getTypeFormatId
in interfaceTypedFormat
- Returns:
- The identifier. (A UUID stuffed in an array of 16 bytes).
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equals
Test for value equality -
hashCode
public int hashCode()
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