Database Programming with JDBC & Java, Second Edition

Name

Blob

Synopsis

Interface Name: java.sql.Blob

Superclass: None

Immediate Subclasses: None

Interfaces Implemented: None

Availability: New as of JDK 1.2

Description

This object represents a SQL BLOB. BLOB stands for “binary large object” and is a relational database representation of a large piece of binary data. The value of using a BLOB is that you can manipulate the BLOB as a Java object without retrieving all of the data behind the BLOB from the database. A BLOB object is only valid for the duration of the transaction in which it was created.

Class Summary

public interface Blob {
    InputStream getBinaryStream( ) throws SQLException;
    byte[] getBytes(long pos, int count) 
        throws SQLException;
    long length( ) throws SQLException;
    long position(byte[] pattern, long start) 
        throws SQLException;
    long position(Blob pattern, long start)
        throws SQLException;
}

Object Methods

getBinaryStream( )

public InputStream getBinaryStream( ) throws SQLException

Description

This method retrieves the data that makes up the binary object as a stream from the database.

getBytes( )

public byte[] getBytes(long pos, int count) 
    throws SQLException

Description

This method returns the data that makes up the underlying binary object in part or in whole as an array of bytes. You can get a subset of the binary data by specifying a nonzero starting index or a number of bytes less than the object’s length.

length( )

public long length( ) throws SQLException

Description

This method provides the number of bytes that make up the BLOB.