Updatable result sets

In Derby, the functionality of updatable result sets in a server environment and in an embedded environment are similar, with the exception of the following differences:

The Network Client requires that there be at least one column in the select list from the target table. For example, the following statement will fail in a server environment:
```
select 1, 2 from t1 for update of c11
```
The Network Client driver looks at both of the columns in the select list and cannot determine the target table for update/delete by looking at the column metadata. This requirement is not necessary in an embedded environment.
The embedded driver allows for statement name changes when there is an open result set on the statement object. This is not supported in a server environment.

Other differences between updatable result sets in a server or embedded environment can be found in the following table.

Table 1. Comparison of updatable result sets features in server and embedded environments
Feature	Embedded Environment	Server Environment
updateBytes on CHAR, VARCHAR, LONG VARCHAR datatypes	Supported	Not supported
updateTime on TIMESTAMP datatypes	Supported	Not supported
updateClob and updateBlob	Supported	Not supported