question: private Collection < Var > migrateColumns ( SQLTable currentTable ) { List < Var > vars = new ArrayList < > ( ) ; String tableType = currentTable . getEntityType ( ) ; Map < String , ResourceType . DataType > columns = currentTable . getColumns ( ) ; Map < String , String > foreignColumns = currentTable . getForeignKeyColumns ( ) ; for ( String column : columns . keySet ( ) ) { ResourceType . DataType columnType = columns . get ( column ) ; if ( foreignColumns . containsKey ( column ) ) { vars . addAll ( migrateAsRelation ( tableType , column , foreignColumns . get ( column ) ) ) ; } else { vars . addAll ( migrateAsResource ( tableType , columnType , column ) ) ; } } return vars ; }
target:  Loop through each of the columns in the given table, migrating each as a resource or relation.