org.hsqldb.jdbc
Class JDBCRowId

java.lang.Object
  org.hsqldb.jdbc.JDBCRowId

All Implemented Interfaces:

RowId

public final class JDBCRowId
extends Object
implements RowId

The representation (mapping) in the Java programming language of an SQL ROWID value. An SQL ROWID is a built-in type, a value of which can be thought of as an address for its identified row in a database table. Whether that address is logical or, in any respects, physical is determined by its originating data source.

Methods in the interfaces ResultSet, CallableStatement, and PreparedStatement, such as getRowId and setRowId allow a programmer to access a SQL ROWID value. The RowId interface provides a method for representing the value of the ROWID as a byte array or as a String.

The method getRowIdLifetime in the interface DatabaseMetaData, can be used to determine if a RowId object remains valid for the duration of the transaction in which the RowId was created, the duration of the session in which the RowId was created, or, effectively, for as long as its identified row is not deleted. In addition to specifying the duration of its valid lifetime outside its originating data source, getRowIdLifetime specifies the duration of a ROWID value's valid lifetime within its originating data source. In this, it differs from a large object, because there is no limit on the valid lifetime of a large object within its originating data source.

All methods on the RowId interface must be fully implemented if the JDBC driver supports the data type.

Since:

JDK 1.6, HSQLDB 2.0

Author:

boucherb@users

See Also:

DatabaseMetaData

Constructor Summary

JDBCRowId(byte[] id)
Constructs a new JDBCRowId instance wrapping the given octet sequence.

JDBCRowId(RowId id)
Constructs a new JDBCRowId instance whose internal octet sequence is is a copy of the octet sequence of the given RowId object.

JDBCRowId(String hex)
Constructs a new JDBCRowId instance whose internal octet sequence is is that represented by the given hexidecimal character sequence.

Method Summary

boolean	equals(Object obj) Compares this RowId to the specified object.
byte[]	getBytes() Returns an array of bytes representing the value of the SQL ROWID designated by this java.sql.RowId object.
int	hashCode() Returns a hash code value of this RowId object.
String	toString() Returns a String representing the value of the SQL ROWID designated by this java.sql.RowId object.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

JDBCRowId

public JDBCRowId(byte[] id)
          throws SQLException

Constructs a new JDBCRowId instance wrapping the given octet sequence.

This constructor may be used internally to retrieve result set values as RowId objects, yet it also may need to be public to allow access from other packages. As such (in the interest of efficiency) this object maintains a reference to the given octet sequence rather than making a copy; special care should be taken by extenal clients never to use this constructor with a byte array object that may later be modified extenally.

Parameters:

id - the octet sequence representing the Rowid value

Throws:

SQLException - if the argument is null

JDBCRowId

public JDBCRowId(RowId id)
          throws SQLException

Constructs a new JDBCRowId instance whose internal octet sequence is is a copy of the octet sequence of the given RowId object.

Parameters:

id - the octet sequence representing the Rowid value

Throws:

SQLException - if the argument is null

JDBCRowId

public JDBCRowId(String hex)
          throws SQLException

Constructs a new JDBCRowId instance whose internal octet sequence is is that represented by the given hexidecimal character sequence.

Parameters:

hex - the hexadecimal character sequence from which to derive the internal octet sequence

Throws:

SQLException - if the argument is null or is not a valid hexadecimal character sequence

Method Detail

equals

public boolean equals(Object obj)

Compares this RowId to the specified object. The result is true if and only if the argument is not null and is a RowId object that represents the same ROWID as this object.

It is important to consider both the origin and the valid lifetime of a RowId when comparing it to another RowId. If both are valid, and both are from the same table on the same data source, then if they are equal they identify the same row; if one or more is no longer guaranteed to be valid, or if they originate from different data sources, or different tables on the same data source, they may be equal but still not identify the same row.

Specified by:

equals in interface RowId

Overrides:

equals in class Object

Parameters:

obj - the Object to compare this RowId object against.

Returns:

true if the RowIds are equal; false otherwise

Since:

JDK 1.6, HSQLDB 2.0

getBytes

public byte[] getBytes()

Returns an array of bytes representing the value of the SQL ROWID designated by this java.sql.RowId object.

Specified by:

getBytes in interface RowId

Returns:

an array of bytes, whose length is determined by the driver supplying the connection, representing the value of the ROWID designated by this java.sql.RowId object.

toString

public String toString()

Returns a String representing the value of the SQL ROWID designated by this java.sql.RowId object.

Like java.sql.Date.toString() returns the contents of its DATE as the String "2004-03-17" rather than as DATE literal in SQL (which would have been the String DATE "2004-03-17"), toString() returns the contents of its ROWID in a form specific to the driver supplying the connection, and possibly not as a ROWID literal.

Specified by:

toString in interface RowId

Overrides:

toString in class Object

Returns:

a String whose format is determined by the driver supplying the connection, representing the value of the ROWID designated by this java.sql.RowId object.

hashCode

public int hashCode()

Returns a hash code value of this RowId object.

Specified by:

hashCode in interface RowId

Overrides:

hashCode in class Object

Returns:

a hash code for the RowId