greetings all, I am using ConfigurationOfODBC in Pharo 1.3. I have had success with getting an ODBCResultTable(OrderedCollection) containing ODBCRow containing about 30 fields. By default the fields are accessed by "row at: #fieldName" but I wanted to add some convenience methods to instead go "row fieldName." My searching and experimentation led me to subclassing ODBCRow as EAPPackage and then using "adoptInstance:" on each ODBCRow to convert it to the subclass. This was to avoid having to having to understand and change any of the ConfigurationOfODBC code. I had tried copyFrom: but some of the instance variables inherited from ODBCRow were not filled in, generating exceptions in some of the inherited methods. I had also considered "become:" but that didn't seem appropriate. Using "adoptInstance:" worked fine until I added a new instance variable to EAPPackage. Subsequently for "<primitive: 160 error: ec>", ec = #'bad receiver'. The "adoptInstance:" method comment says it follows the same rules as "primitiveChangeClassTo:" (yet note that "primitiveChangeClassTo:" never worked) The "primitiveChangeClassTo:" method comment says "The primitive will fail in most cases that you think might work [...] The facility is really provided for certain, very specific applications (mostly related to classes changing shape) and not for casual use" so I wondered if there was another way to achieve this. The full code is hopefully not too long to include for reference below. The use of "adoptInstance:" in the last section listed. ------ ODBCRow subclass: #EAPPackage instanceVariableNames: 'parent' "note adoptInstance works without this instance variable, and not with" classVariableNames: '' poolDictionaries: '' category: 'BTC-EA-Explore' ------ EAPPackage >> name ^ self at: #Name ------ ODBCResultTable subclass: #EAPPackages instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'BTC-EA-Explore' ------ EAPPackages class >> newFromConnection: connection | packages parent | packages := (connection query: 'select * from t_package;') execute asTable. self adoptInstance: packages. packages do: [ :row | EAPPackage adoptInstance: row. ]. ^packages. ------ In a Workspace I successfully evaluate the following three lines without : connection := ODBCConnection dsn: 'CIM' user: '' password: ''. packages := EAPPackages newFromConnection: connection. connection close. ------ I found the ODBCRow instance creation to ODBCResultSet>>fetchRow. One alternative I've considered is to somehow pass through a custom SomeClass in a variable to replace the hard reference to ODBCRow - but I don't want to chase back all the cascading call references. Is there another way to change an existing object to another class, such that it can be specialised with both additional methods and instance variables? I would appreciate any pointers. regards, Ben