怎样将mongodb 在java中对应的方法，转换成SQL的

如下例所示： 现在还数据库了（postgreSQL），我该把这些方法转换成相对应的什么方法？ 求解答
protected DBObject createWaveletDBQuery() {
DBObject query = new BasicDBObject();
query.put(MongoDbDeltaStoreUtil.FIELD_WAVE_ID, waveletName.waveId.serialise());
query.put(MongoDbDeltaStoreUtil.FIELD_WAVELET_ID, waveletName.waveletId.serialise());
return query;
}

public WaveletDeltaRecord getDelta(long version) throws IOException {

DBObject query = createWaveletDBQuery();
query.put(MongoDbDeltaStoreUtil.FIELD_TRANSFORMED_APPLIEDATVERSION, version);

DBObject result = deltaDbCollection.findOne(query);

WaveletDeltaRecord waveletDelta = null;

if (result != null) try {
  waveletDelta = MongoDbDeltaStoreUtil.deserializeWaveletDeltaRecord(result);
} catch (PersistenceException e) {
  throw new IOException(e);
}
return waveletDelta;

}