Introduction to JDBC - Java Database Programming Bible - page 156

Table 4-6: SQL3 Data Type Reference Methods

SQL3 type get set update

BLOB getBlob seBlob updateBlob

CLOB getClob setClob updateClob

ARRAY getArray setArray updateArray

Structured type getObject setObject updateObject

REF ( structured type) getObject setObject updateObject

At the time of this writing, the update methods are scheduled for future
release. Until then, you can use the method updateObject, which works
just as well.

Note

Here's an example of accessing one of these new data types. The following code
fragment retrieves a CLOB value, Notes, from a patient's medical records.

ResultSet rs = stmt.executeQuery(
"SELECT Notes FROM Patients WHERE SSN = 123-45-6789");
rs.next();
Clob notes = rs.getClob("Notes");

Because a SQL BLOB, CLOB, or ARRAY object may be very large, an instance of
any o f these types is actually a SQL locator or logical pointer to the object in the
database that the instance represents. JDBC provides the tools to manipulate them
without having to bring all of their data from the database server to your client
machine. This feature can make performance significantly faster.

If you want to bring the data of a BLOB or CLOB value to the client, you can use the
following methods in the Blob and Clob interfaces provided for this purpose:

getAsciiStream()(Gets the CLOB value designated by this Clob object as a stream of ASCII
bytes)

getCharacterStream() (Gets the Clob contents as a Unicode stream)

getSubString(long pos, int length)(Returns a copy of the specified substring in the CLOB value
designated by this Clob object)

length()(Returns the number of characters in the CLOB value designated by this Clob object)

position(Clob searchstr, long start) (Determines the character position at which the specified
Clob object searchstr appears in this Clob object)

position(String searchstr, long start) (Determines the character position at which the specified
substring searchstr appears in the CLOB)