Using schema transformation pathways for data lineage tracing

With the increasing amount and diversity of information available on the Internet, there has been a huge growth in information systems that need to integrate data from distributed, heterogeneous data sources. Tracing the lineage of the integrated data is one of the problems being addressed in data warehousing research. This paper presents a data lineage tracing approach based on schema transformation pathways. Our approach is not limited to one specific data model or query language, and would be useful in any data transformation/integration framework based on sequences of primitive schema transformations

Discovering data lineage in data warehouse : methods and techniques for tracing the origins of data in data-warehouse

A data warehouse enables enterprise-wide analysis and reporting functionality that is usually used to support decision-making. Data warehousing system integrates data from different data sources. Typically, the data are extracted from different data sources, then transformed several times and integrated before they are finally stored in the central repository. The extraction and transformation processes vary widely - both in theory and between solution providers. Some are generic, others are tailored to users' transformation and reporting requirements through hand-coded solutions. Most research related to data integration is focused on this area, i.e., on the transformation of data. Since data in a data warehouse undergo various complex transformation processes, often at many different levels and in many stages, it is very important to be able to ensure the quality of the data that the data warehouse contains. The objective of this thesis is to study and compare existing approaches (methods and techniques) for tracing data lineage, and to propose a data lineage solution specific to a business enterprise data warehouse

Općeniti postupak za i ntegracijsko testiranje ETL procedura

In order to attain a certain degree of confidence in the quality of the data in the data warehouse it is necessary to perform a series of tests. There are many components (and aspects) of the data warehouse that can be tested, and in this paper we focus on the ETL procedures. Due to the complexity of ETL process, ETL procedure tests are usually custom written, having a very low level of reusability. In this paper we address this issue and work towards establishing a generic procedure for integration testing of certain aspects of ETL procedures. In this approach, ETL procedures are treated as a black box and are tested by comparing their inputs and outputs – datasets. Datasets from three locations are compared: datasets from the relational source(s), datasets from the staging area and datasets from the data warehouse. Proposed procedure is generic and can be implemented on any data warehouse employing dimensional model and having relational database(s) as a source. Our work pertains only to certain aspects of data quality problems that can be found in DW systems. It provides a basic testing foundation or augments existing data warehouse system’s testing capabilities. We comment on proposed mechanisms both in terms of full reload and incremental loading.Kako bi se ostvarila određena razina povjerenja u kvalitetu podataka potrebno je obaviti niz provjera. Postoje brojne komponente (i aspekti) skladišta podataka koji se mogu testirati. U ovom radu smo se usredotočili na testiranje ETL procedura. S obzirom na složenost sustava skladišta podataka, testovi ETL procedura se pišu posebno za svako skladište podataka i rijetko se mogu ponovo upotrebljavati. Ovdje se obrađuje taj problem i predlaže općenita procedura za integracijsko testiranje određ enih aspekata ETL procedura. Predloženi pristup tretira ETL procedure kao crnu kutiju, te se procedure testiraju tako što se uspoređuju ulazni i izlazni skupovi podataka. Uspoređuju se skupovi podataka s tri lokacije: podaci iz izvorišta podataka, podaci iz konsolidiranog pripremnog područja te podaci iz skladišta podataka. Predložena procedura je općenita i može se primijeniti na bilo koje skladište podatka koje koristi dimenzijski model pri čemu podatke dobavlja iz relacijskih baza podataka. Predložene provjere se odnose samo na određene aspekte problema kvalitete podataka koji se mogu pojaviti u sustavu skladišta podataka, te služe za uspostavljanje osnovnog skupa provjera ili uvećanje mogućnosti provjere postojećih sustava. Predloženi postupak se komentira u kontekstu potpunog i inkrementalnog učitavanja podataka u skladište podataka

On the Limitations of Provenance for Queries With Difference

The annotation of the results of database transformations was shown to be very effective for various applications. Until recently, most works in this context focused on positive query languages. The provenance semirings is a particular approach that was proven effective for these languages, and it was shown that when propagating provenance with semirings, the expected equivalence axioms of the corresponding query languages are satisfied. There have been several attempts to extend the framework to account for relational algebra queries with difference. We show here that these suggestions fail to satisfy some expected equivalence axioms (that in particular hold for queries on "standard" set and bag databases). Interestingly, we show that this is not a pitfall of these particular attempts, but rather every such attempt is bound to fail in satisfying these axioms, for some semirings. Finally, we show particular semirings for which an extension for supporting difference is (im)possible.Comment: TAPP 201

Modélisation et extraction de données pour un entrepôt objet

National audienceThis paper describes an object-oriented model for designing complex and time-variant data warehouse data. The main contribution is the warehouse class concept, which extends the class concept by temporal and archive filters as well as a mapping function. Filters allow the keeping of relevant data changes whereas the mapping function defines the warehouse class schema from a global data source schema. The approach take into account static properties as well as dynamic properties. The behaviour extraction is based on the use-matrix concept

Causality and the semantics of provenance

Provenance, or information about the sources, derivation, custody or history of data, has been studied recently in a number of contexts, including databases, scientific workflows and the Semantic Web. Many provenance mechanisms have been developed, motivated by informal notions such as influence, dependence, explanation and causality. However, there has been little study of whether these mechanisms formally satisfy appropriate policies or even how to formalize relevant motivating concepts such as causality. We contend that mathematical models of these concepts are needed to justify and compare provenance techniques. In this paper we review a theory of causality based on structural models that has been developed in artificial intelligence, and describe work in progress on a causal semantics for provenance graphs.Comment: Workshop submissio