Ensure that all parameters in this list have been
assigned values. Return silently if all is well, otherwise
throw an appropriate exception.
throws: SQLException - if not all parameters are set.
Return a list of the SimpleParameterList objects that
make up this parameter list. If this object is already a
SimpleParameterList, returns null (avoids an extra array
construction in the common case).
an array of single-statement parameter lists, ornull if this object is already a single-statementparameter list.