Query based insertion or updating of blob values
Suppose an application wants to display a list of contacts in alphabetical order by lastname, firstname, in a scrolling window that can only show 7 contacts at a time.
Initialize the scrolling window to the first 7 entries is easy: OFFSET gives the correct answer.
If Open JPA cannot detect what type of database you are using, or if you are using an unsupported database, you will have to tell Open JPA what The standard dictionaries all recognize the following properties.
Two row values are compared by looking at the constituent scalar values from left to right. The overall result of comparison is NULL if it is possible to make the result either true or false by substituting alternative values in place of the constituent NULLs.
The following query demonstrates some row value comparisons: The result of "(1,2,3)=(1, NULL,3)" is NULL because the result might be true if we replaced NULL→2 or false if we replaced NULL→9.
Among the other stuff enumerated as binary data, you can also store binary representations of text - This may seem like a silly question, but what do you actually want to use a RDBMS for ?
If you just want to store files, then the operating system's filesystem is generally adequate.