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java.sql
Interface Blob

public interface Blob

JDBC 2.0

The representation (mapping) in the Java^TM programming language of an SQL BLOB. An SQL BLOB is a built-in type that stores a Binary Large Object as a column value in a row of a database table. The driver implements Blob using an SQL locator(BLOB), which means that a Blob object contains a logical pointer to the SQL BLOB data rather than the data itself. A Blob object is valid for the duration of the transaction in which is was created.

Methods in the interfaces ResultSet, CallableStatement, and PreparedStatement, such as getBlob and setBlob allow a programmer to access the SQL BLOB. The Blob interface provides methods for getting the length of an SQL BLOB (Binary Large Object) value, for materializing a BLOB value on the client, and for determining the position of a pattern of bytes within a BLOB value.

Method Summary

InputStream	getBinaryStream() Retrieves the BLOB designated by this Blob instance as a stream.
byte[]	getBytes(long pos, int length) Returns as an array of bytes part or all of the BLOB value that this Blob object designates.
long	length() Returns the number of bytes in the BLOB value designated by this Blob object.
long	position(Blob pattern, long start) Determines the byte position in the BLOB value designated by this Blob object at which pattern begins.
long	position(byte[] pattern, long start) Determines the byte position at which the specified byte pattern begins within the BLOB value that this Blob object represents.

Method Detail

length

public long length()
            throws SQLException

Returns the number of bytes in the BLOB value designated by this Blob object.

Returns:

length of the BLOB in bytes

Throws:

SQLException - if there is an error accessing the length of the BLOB

getBytes

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

Returns as an array of bytes part or all of the BLOB value that this Blob object designates. The byte array contains up to length consecutive bytes starting at position pos.

Parameters:

pos - the ordinal position of the first byte in the BLOB value to be extracted; the first byte is at position 1

length - is the number of consecutive bytes to be copied

Returns:

a byte array containing up to length consecutive bytes from the BLOB value designated by this Blob object, starting with the byte at position pos.

Throws:

SQLException - if there is an error accessing the BLOB

getBinaryStream

public InputStream getBinaryStream()
                            throws SQLException

Retrieves the BLOB designated by this Blob instance as a stream.

Returns:

a stream containing the BLOB data

Throws:

SQLException - if there is an error accessing the BLOB

position

public long position(byte[] pattern,
                     long start)
              throws SQLException

Determines the byte position at which the specified byte pattern begins within the BLOB value that this Blob object represents. The search for patternstart.

Parameters:

pattern - the byte array for which to search

start - the position at which to begin searching; the first position is 1

Returns:

the position at which the pattern appears, else -1.

Throws:

SQLException - if there is an error accessing the BLOB

position

public long position(Blob pattern,
                     long start)
              throws SQLException

Determines the byte position in the BLOB value designated by this Blob object at which pattern begins. The search begins at position start.

Parameters:

pattern - the Blob object designating the BLOB value for which to search

start - the position in the BLOB value at which to begin searching; the first position is 1

Returns:

the position at which the pattern begins, else -1

Throws:

SQLException - if there is an error accessing the BLOB