Why do I have to reaccess the database for Array, Blob, and Clob data?
Location: http://www.jguru.com/faq/view.jsp?EID=594583 Created: Dec 23, 2001 Author: Joe Sam Shirah (http://www.jguru.com/guru/viewbio.jsp?EID=42100) Most DBMS vendors have implemented these types via the SQL3 Locator type ( see What is an SQL Locator? and the JDBC 2.1 core API specifies “By default, a JDBC driver should implement the Blob and Clob interfaces using the appropriate locator type.” The same is true for the Array interface. Some rationales for using Locators rather than directly returning the data can be seen most clearly with the Blob type. By definition, a Blob is an arbitrary set of binary data. It could be anything; the DBMS has no knowledge of what the data represents. Notice that this effectively demolishes data independence, because applications must now be aware of what the Blob data actually represents. Let’s assume an employee table that includes employee images as Blobs. Say we have an inquiry program that presents multiple employees with department and identifi
