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How does Empire-DB handle '' (empty string)?

Empire-DB internally treats all empty strings as null and this behavior is by design.
Some databases accept empty strings as a valid value for a text column, others don’t.
However allowing empty strings is a major reason for many database problems and changing the empire-db code here would have a major impact on existing projects.
We have thought about this a long time ago and we came to the conclusion that empty strings are evil and should be avoided completely.
In fact NULL has a logical meaning of a value not being supplied for a field but what different logical meaning would an empty string have instead?

In some rare cases however you might need to explicitly use an empty string rather than null.
One of it is with existing databases when you want to search for field that contain an empty string. In this case (and others) you must explicitly say that you want to use an empty string. This is possible through the DBDatabase.EMPTY_STRING constant.

The following example shows how to replace all empty strings of a column by null:

DBCommand cmd = db.createCommand();           
cmd.set  (db.EMPLOYEES.LASTNAME.to( null ));
cmd.where(db.EMPLOYEES.LASTNAME.is( DBDatabase.EMPTY_STRING ));
db.executeSQL(cmd.getUpdate(), conn);

This will generate:

UPDATE EMPLOYEES
SET LASTNAME=null
WHERE LASTNAME=''

Is DBDatabase (and related DBTable, DBColumn) thread-safe?

...

See these projects for more info about connection pools:

• http://c3p0.sourceforge.net^{Image Removed}
• http://commons.apache.org/dbcp/^{Image Removed}
• http://proxool.sourceforge.net^{Image Removed}

Do you have a Scala integration module?

None of us has experience with Scala, but feel free to contribute. This blog post might also help as it points to a project that integrates Scala and empire-db: http://www.acooke.org/cute/UsingScala0.html^{Image Removed}

How do I set the maximum number of rows returned

cmd.limitRows(…)
cmd.skipRows(…) //to set the offset.