RowId

  • RowId represents an SQL ROWID value in Java, acting like an address for a specific row in a database table.

  • It provides methods to access and represent the ROWID value as a byte array or a String.

  • The lifetime validity of a RowId can vary and is determined by the data source and can be checked using DatabaseMetaData.getRowIdLifetime.

  • RowId objects can be compared for equality but their validity and origin should be considered for accurate comparisons.

  • JDBC drivers supporting the ROWID data type must fully implement all methods in the RowId interface.
public interface 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.

See Also

Public Method Summary

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

Public Methods

public abstract 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.

Parameters
obj the Object to compare this RowId object against.
Returns
  • true if the RowIds are equal; false otherwise

public abstract byte[] getBytes ()

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

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.

public abstract int hashCode ()

Returns a hash code value of this RowId object.

Returns
  • a hash code for the RowId

public abstract 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.

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.