gistfile1.cs

        HashSet<string> GetCommonDatasetNames(string oldIdentityId, string newIdentityId){
            HashSet<string> newNameSet = new HashSet<string>();
            HashSet<string> oldNameSet = new HashSet<string>();
            if(oldIdentityId != null && newIdentityId != null){
                List<DatasetMetadata> newDatasets = GetDatasets(newIdentityId);
                List<DatasetMetadata> oldDatasets = GetDatasets(oldIdentityId);
                foreach(DatasetMetadata oldMetaData in oldDatasets){
                    oldNameSet.Add(oldMetaData.DatasetName);
                }
                foreach(DatasetMetadata newMetaData in newDatasets){
                    newNameSet.Add(newMetaData.DatasetName);
                }
                oldNameSet.IntersectWith(newNameSet);
            }
            return oldNameSet;
        }

        public override void ChangeIdentityId(string oldIdentityId, string newIdentityId)
        {
            Debug.Log ("Reparenting datasets from " + oldIdentityId + " to " + newIdentityId);
            GetCommonDatasetNames(oldIdentityId, newIdentityId);
            lock (SQLiteDatabase.SQLiteLock)
            {
                SQLiteStatement stmt = null;
                try {
                    // if oldIdentityId is unknown, aka the dataset is created prior to
                    // having a cognito id, just reparent datasets from unknown to
                    // newIdentityId
                    if (DatasetUtils.UNKNOWN_IDENTITY_ID == oldIdentityId) {

                        HashSet<string> commonDatasetNames = GetCommonDatasetNames(oldIdentityId, newIdentityId);
                        
                        // append UNKNOWN to the name of all non unique datasets
                        foreach(String oldDatasetName in commonDatasetNames){

                                stmt = db.Prepare("UPDATE " + TABLE_DATASETS
                                      + " SET " + DatasetColumns.DATASET_NAME + " = ?"
                                      + " WHERE " + DatasetColumns.IDENTITY_ID + " = ?"
                                      + " AND " + DatasetColumns.DATASET_NAME + " = ?"
                                );

                                DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
                                string timestamp = ((DateTime.UtcNow - epoch).TotalSeconds).ToString();
                
                                stmt.BindText(1, oldDatasetName+"."+oldIdentityId+"-"+timestamp);
                                stmt.BindText(2, oldIdentityId);
                                stmt.BindText(3, oldDatasetName);

                                stmt.Step();

                                stmt.FinalizeStm();

                                stmt = db.Prepare("UPDATE " + TABLE_RECORDS
                                    + " SET " + RecordColumns.DATASET_NAME + " = ?"
                                    + " WHERE " + RecordColumns.IDENTITY_ID + " = ?"
                                    + " AND " + RecordColumns.DATASET_NAME + " = ?"
                                );
                                
                                stmt.BindText(1, oldDatasetName+"."+oldIdentityId+"-"+timestamp);
                                stmt.BindText(2, oldIdentityId);
                                stmt.BindText(3, oldDatasetName);

                                stmt.Step();
                                
                                stmt.FinalizeStm();
                        }

                        stmt = db.Prepare(
                            DatasetColumns.BuildUpdate(
                                new string[] { DatasetColumns.IDENTITY_ID },
                                DatasetColumns.IDENTITY_ID + " = ?"
                            )
                        );
                        
                        stmt.BindText(1, newIdentityId);
                        stmt.BindText(2, oldIdentityId);
                        
                        stmt.Step();
                        
                        stmt.FinalizeStm();
                        
                        
                        stmt = db.Prepare(
                            RecordColumns.BuildUpdate(
                                new string[] { RecordColumns.IDENTITY_ID },
                                RecordColumns.IDENTITY_ID + " = ?"
                            )
                        );
                        
                        
                        stmt.BindText(1, newIdentityId);
                        stmt.BindText(2, oldIdentityId);
                        
                        stmt.Step();

                    } else {
                        // 1. copy oldIdentityId/dataset to newIdentityId/dataset
                        // datasets table
                        stmt = db.Prepare("INSERT INTO " + TABLE_DATASETS + "("
                            + DatasetColumns.IDENTITY_ID + ","
                            + DatasetColumns.DATASET_NAME + ","
                            + DatasetColumns.CREATION_TIMESTAMP + ","
                            + DatasetColumns.STORAGE_SIZE_BYTES + ","
                            + DatasetColumns.RECORD_COUNT
                            // last sync count is reset to default 0
                            + ")"
                            + " SELECT "
                            + "'" + newIdentityId + "'," // assign new owner
                            + DatasetColumns.DATASET_NAME + ","
                            + DatasetColumns.CREATION_TIMESTAMP + ","
                            + DatasetColumns.STORAGE_SIZE_BYTES + ","
                            + DatasetColumns.RECORD_COUNT
                            + " FROM " + TABLE_DATASETS
                            + " WHERE " + DatasetColumns.IDENTITY_ID + " = ?"
                        );

                        stmt.BindText(1, oldIdentityId);

                        stmt.Step();
                        stmt.FinalizeStm();

                        // records table
                        stmt = db.Prepare("INSERT INTO " + TABLE_RECORDS + "("
                            + RecordColumns.IDENTITY_ID + ","
                            + RecordColumns.DATASET_NAME + ","
                            + RecordColumns.KEY + ","
                            + RecordColumns.VALUE + ","
                            // sync count is resset to default 0
                            + RecordColumns.LAST_MODIFIED_TIMESTAMP + ","
                            + RecordColumns.LAST_MODIFIED_BY + ","
                            + RecordColumns.DEVICE_LAST_MODIFIED_TIMESTAMP
                            // modified is reset to default 1 (dirty)
                            + ")"
                            + " SELECT "
                            + "'" + newIdentityId + "'," // assign new owner
                            + RecordColumns.DATASET_NAME + ","
                            + RecordColumns.KEY + ","
                            + RecordColumns.VALUE + ","
                            + RecordColumns.LAST_MODIFIED_TIMESTAMP + ","
                            + RecordColumns.LAST_MODIFIED_BY + ","
                            + RecordColumns.DEVICE_LAST_MODIFIED_TIMESTAMP
                            + " FROM " + TABLE_RECORDS
                            + " WHERE " + RecordColumns.IDENTITY_ID + " = ?"
                        );

                        stmt.BindText(1, oldIdentityId);

                        stmt.Step();
                        stmt.FinalizeStm();

                        // 2. rename oldIdentityId/dataset to
                        // newIdentityId/dataset.oldIdentityId
                        // datasets table
                        stmt = db.Prepare("UPDATE " + TABLE_DATASETS
                            + " SET "
                            + DatasetColumns.IDENTITY_ID + " = '" + newIdentityId + "', "
                            + DatasetColumns.DATASET_NAME + " = "
                            + DatasetColumns.DATASET_NAME + " || '." + oldIdentityId + "'"
                            + " WHERE " + DatasetColumns.IDENTITY_ID + " = ?"
                        );

                        stmt.BindText(1, oldIdentityId);

                        stmt.Step();
                        stmt.FinalizeStm();

                        // records table
                        stmt = db.Prepare("UPDATE " + TABLE_RECORDS
                            + " SET "
                            + RecordColumns.IDENTITY_ID + " = '" + newIdentityId + "', "
                            + RecordColumns.DATASET_NAME + " = "
                            + RecordColumns.DATASET_NAME + " || '." + oldIdentityId + "'"
                            + " WHERE " + RecordColumns.IDENTITY_ID + " = ?"
                        );

                        stmt.BindText(1, oldIdentityId);

                        stmt.Step();
                    }
                } finally {
                    stmt.FinalizeStm();
                }
            }
                    
        }