TY - CHAP A1 - Braun, Stefan A1 - Schildgen, Johannes A1 - Deßloch, Stefan T1 - Visualization of NoSQL transformations using sampling techniques | Visualisierung von NoSQL-Transformationen unter der Verwendung von Sampling-Techniken T2 - Proceedings of the LWA 2015 workshops: KDML, FGWM, IR, and FGDB : Trier, Germany, October 7-9, 2015 N2 - Analysen auf NoSQL-Datenbanken sind oft langdauernd und die Ergebnisse fur den Benutzer haufig schwer verst ̈andlich. Wir prasentieren eine Möglichkeit, Datenmengen aus Wide-Column Stores mittels der Transformationssprache NotaQL zu transformieren sowie zu aggregieren und die Ergebnisse in Form von Diagrammen dem Benutzer darzustellen. Dabei kommen Sampling-Techniken zum Einsatz, um die Berechnung auf Kosten der Genauigkeit zu beschleunigen. Das von uns verwendete iterative Samplingverfahren sorgt fur eine kontinuierliche Verbesserung der Berechnungsgenauigkeit und bietet zudem Möglichkeiten zur Genauigkeitsabschätzung, die in Form von Konfidenzintervallen in den Diagrammen dargestellt werden kann. Y1 - 2015 UR - https://ceur-ws.org/Vol-1458/H06_CRC77_Braun.pdf SP - 427 EP - 438 PB - RWTH Aachen CY - Aachen ER - TY - CHAP A1 - Schäfer, Marc A1 - Schildgen, Jürgen A1 - Deßloch, Stefan T1 - Sampling with Incremental MapReduce T2 - Datenbanksysteme für Business, Technologie und Web (BTW 2015) : Workshopband ; 02. - 03. März 2015 in Hamburg N2 - The goal of this paper is to increase the computation speed of MapReduce jobs by reducing the accuracy of the result. Often, the timely processing is more important than the precision of the result. Hadoop has no built-in functionality for such an approximation technique, so the user has to implement sampling techniques manually. We introduce an automatic system for computing arithmetic approximations. The sampling is based on techniques from statistics and the extrapolation is done generically. This system is also extended by an incremental component which enables the reuse of already computed results to enlarge the sampling size. This can be used iteratively to further increase the sampling size and also the precision of the approximation. We present a transparent incremental sampling approach, so the developed components can be integrated in the Hadoop framework in a non-invasive manner. Y1 - 2015 UR - https://btw-2015.informatik.uni-hamburg.de/res/proceedings/Workshops/DMS/Schaefer-Sampling_with_Incremental_.pdf VL - 242 SP - 121 EP - 130 PB - Gesellschaft für Informatik e.V. ER - TY - CHAP A1 - Schildgen, Johannes A1 - Krück, Yannick A1 - Deßloch, Stefan ED - Mitschang, Bernhard ED - Nicklas, Daniela ED - Leymann, Frank ED - Schöning, Harald ED - Herschel, Melanie ED - Teubner, Jens ED - Härder, Theo ED - Kopp, Oliver ED - Wieland, Matthias T1 - Transformations on Graph Databases for Polyglot Persistence with NotaQL T2 - Datenbanksysteme für Business, Technologie und Web, 17. Fachtagung des GI-Fachbereichs "Datenbanken und Informationssyteme" (DBIS) : 06.-10.03.2017 in Stuttgart, Deutschland (BTW 2017) Y1 - 2017 IS - CD-ROM SP - 83 EP - 102 PB - Gesellschaft für Informatik, Bonn ER - TY - CHAP A1 - Schildgen, Johannes A1 - Deßloch, Stefan ED - Maneth, Sebastian T1 - NotaQL is not a query language! It’s for data transformation on wide-column stores T2 - Data Science : 30th British International Conference on Databases, BICOD 2015 Edingburgh, UK, July 6-8, 2015, Proceedings N2 - It is simple to query a relational database because all columns of the tables are known and the language SQL is easily applicable. In NoSQL, there usually is no fixed schema and no query language. In this article, we present NotaQL, a data-transformation language for wide-column stores. NotaQL is easy to use and powerful. Many MapReduce algorithms like filtering, grouping, aggregation and even breadth-first-search, PageRank and other graph and text algorithms can be expressed in two or three short lines of code. KW - NoSQL KW - Transformation KW - Language KW - Wide-column stores Y1 - 2015 SN - 978-3-319-20423-9 SN - 978-3-319-20424-6 U6 - https://doi.org/10.1007/978-3-319-20424-6_14 SN - 1611-3349 SN - 0302-9743 VL - 9147 SP - 139 EP - 151 PB - Springer Nature ER - TY - JOUR A1 - Schildgen, Johannes A1 - Jörg, Thomas A1 - Dossinger, Manuel A1 - Deßloch, Stefan T1 - Marimba: A framework for making MapReduce jobs incremental JF - Proceedings - 2014 IEEE International Congress on Big Data, BigData Congress 2014, 27 June 2014 - 02 July 2014, Anchorage, AK, USA N2 - Many MapReduce jobs for analyzing Big Data require many hours and have to be repeated again and again because the base data changes continuously. In this paper we propose Marimba, a framework for making MapReduce jobs incremental. Thus, a recomputation of a job only needs to process the changes since the last computation. This accelerates the execution and enables more frequent recomputations, which leads to results which are more up-to-date. Our approach is based on concepts that are popular in the area of materialized views in relational database systems where a view can be updated only by aggregating changes in base data upon the previous result. KW - Aggregates KW - Rhythm KW - Computational modeling KW - Programming KW - Google KW - Big data KW - Relational databases Y1 - 2014 U6 - https://doi.org/10.1109/BigData.Congress.2014.27 PB - IEEE ER - TY - CHAP A1 - Schildgen, Johannes A1 - Deßloch, Stefan T1 - SQL-Grundlagen spielend lernen mit dem Text-Adventure SQL Island T2 - Datenbanksysteme für Business, Technologie und Web : (BTW 2015) ; 16. Fachtagung des GI-Fachbereichs "Datenbanken und Informationssysteme" (DBIS), 04. - 06.03.2015 in Hamburg, Germany N2 - Wir pr asentieren SQL Island, ein neuartiges browserbasiertes Lernspiel,welches auf dem Konzept der Text-Adventures basiert. Nach einem Flugzeugabsturzlandet die Spielfigur auf einer Insel. Man redet mit Bewohnern, sammelt Gegenst ̈andeund k ̈apft gegen B ̈osewichte. Die Besonderheit bei diesem Spiel ist jedoch, dass derSpieler seine Figur lediglich mittels SQL-Befehlen steuert. Alle n ̈otigen Befehle wer-den zun ̈achst pr ̈asentiert, sodass keine Vorerfahrung notwendig ist. Nach etwa einerStunde Spielzeit beherrscht der Spieler SELECT-, UPDATE- und DELETE-Anfragensowie Gruppierungen, Aggregationsfunktionen und Joins. Das Spiel kann online aufhttp://www.sql-island.de kostenlos und ohne Registrierung gespielt werden. T2 - Learning SQL basics effortlessly with the text adventure SQL Island Y1 - 2015 UR - https://www.researchgate.net/publication/277565412_SQL-Grundlagen_spielend_lernen_mit_dem_Text-Adventure_SQL_Island VL - 241 SP - 687 EP - 690 PB - Gesellschaft für Informatik e.V. ER - TY - CHAP A1 - Schildgen, Johannes A1 - Lottermann, Thomas A1 - Deßloch, Stefan T1 - Cross-system NoSQL data transformations with NotaQL T2 - BeyondMR '16: Proceedings of the 3rd ACM SIGMOD Workshop on Algorithms and Systems for MapReduce and BeyondJune 2016 N2 - The rising adoption of NoSQL technology in enterprises causes a heterogeneous landscape of different data stores. Different stores provide distinct advantages and disadvantages, making it necessary for enterprises to facilitate multiple systems for specific purposes. This resulting polyglot persistence is difficult to handle for developers since some data needs to be replicated and aggregated between different and within the same stores. Currently, there are no uniform tools to perform these data transformations since all stores feature different APIs and data models. In this paper, we present the transformation language NotaQL that allows cross-system data transformations. These transformations are output-oriented, meaning that the structure of a transformation script is similar to that of the output. Besides, we provide an aggregation-centric approach, which makes aggregation operations as easy as possible. Y1 - 2016 U6 - https://doi.org/10.1145/2926534.2926535 SP - 1 EP - 10 PB - ACM ER - TY - CHAP A1 - Haubold, Florian A1 - Schildgen, Johannes A1 - Scherzinger, Stefanie A1 - Deßloch, Stefan ED - Mitschang, Bernhard T1 - ControVol Flex: Flexible Schema Evolution for NoSQL Application Development T2 - Datenbanksysteme für Business, Technologie und Web (BTW 2017) : 17. Fachtagung des GI-Fachbereichs "Datenbanken und Informationssyteme" (DBIS) : 06.-10.03.2017 in Stuttgart Deutschland N2 - We demonstrate ControVol Flex, an Eclipse plugin for controlled schema evolution in Java applications backed by NoSQL document stores. The sweet spot of our tool are applications that are deployed continuously against the same production data store: Each new release may bring about schema changes that conflict with legacy data already stored in production. The type system internal to the predecessor tool ControVol is able to detect common schema conflicts, and enables developers to resolve them with the help of object-mapper annotations. Our new tool ControVol Flex lets developers choose their schema-migration strategy, whether all legacy data is to be migrated eagerly by means of NotaQL transformation scripts, or lazily, as declared by object-mapper annotations. Our tool is even capable of carrying out both strategies in combination, eagerly migrating data in the background, while lazily migrating data that is meanwhile accessed by the application. From the viewpoint of the application, it remains transparent how legacy data is migrated: Every read access yields an entity that matches the structure that the current application code expects. Our live demo shows how ControVol Flex gracefully solves a broad range of common schema-evolution tasks. KW - Schema evolution KW - NotaQL KW - NoSQL Y1 - 2017 PB - Gesellschaft für Informatik e.V. (GI) CY - Bonn ER -