程序包 java.sql

接口 RowId

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.

从以下版本开始:

1.6

另请参阅:

DatabaseMetaData

方法概要

限定符和类型	方法	说明
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.

方法详细资料

equals

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.

覆盖:

equals 在类中 Object

参数:

obj - the Object to compare this RowId object against.

返回:

true if the RowIds are equal; false otherwise

从以下版本开始:

1.6

另请参阅:

Object.hashCode(), HashMap

getBytes

byte[] getBytes()

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

返回:

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

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.

覆盖:

toString 在类中 Object

返回:

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

int hashCode()

Returns a hash code value of this RowId object.

覆盖:

hashCode 在类中 Object

返回:

a hash code for the RowId

另请参阅:

Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)