sql holder and executer. JDBC has three statement classes: Statement, PreparedStatement, and CallableStatement. RDBC has only one statement class.
initialize(con, sql=nil) You dont have to call it yourself. if sql==nil then self is non-prepared. else self is prepared.
execute(sql=nil)
execute sql.
if sql==nil then prepared sql is executed.
else the sql is executed.
returns true if a ResultSet object is made.
return false if updatecount>=0.
executeQuery(sql=nil) execute. throws an exception if ResultSet object is not made. returns the ResultSet object.
executeUpdate(sql=nil) execute. throws an exception if updatecount < 0. returns updatecount.
close
setParam(index, data) if prepared, you can "set a data to a parameter". index is a name(String) of the parameter.
getParam(index) if prepared, you can "get a data from a parameter". index is a name(String) of the parameter.
resultset returns recent ResultSet object. executeUpdate discards(nil) the object.
updatecount returns recent updatecount. executeQuery discards(-1) the value.