Online Analytical Processing (OLAP) comprises tools and algorithms that allow querying multidimensional databases. It is based on the multidimensional model, where data can be seen as a cube such that each cell contains one or more measures that can be aggregated along dimensions. In a Big Data scenario, traditional data warehousing and OLAP operations are clearly not sufficient to address current data analysis requirements, for example, social network analysis. Furthermore, OLAP operations and models can expand the possibilities of graph analysis beyond the traditional graph-based computation. Nevertheless, there is not much work on the problem of taking OLAP analysis to the graph data model. This paper proposes a formal multidimensional model for graph analysis, that considers the basic graph data, and also background information in the form of dimension hierarchies. The graphs in this model are node- and edge-labelled directed multi-hypergraphs, called graphoids, which can be defined at several different levels of granularity using the dimensions associated with them. Operations analogous to the ones used in typical OLAP over cubes are defined over graphoids. The paper presents a formal definition of the graphoid model for OLAP, proves that the typical OLAP operations on cubes can be expressed over the graphoid model, and shows that the classic data cube model is a particular case of the graphoid data model. Finally, a case study supports the claim that, for many kinds of OLAP-like analysis on graphs, the graphoid model works better than the typical relational OLAP alternative, and for the classic OLAP queries, it remains competitive.
翻译:在线分析处理(OLAP) 由允许查询多维数据库的工具和算法组成。 它基于多维模型, 数据可以被视为一个立方体, 使每个单元格都包含一个或一个以上可以按维度汇总的计量。 在大数据假设中, 传统的数据仓和 OLAP 操作显然不足以满足当前数据分析要求, 例如社交网络分析。 此外, OLAP 操作和模型可以扩大图形分析的可能性, 超越传统的图形计算。 然而, 在将OLAP 分析到图形数据模型上的问题上, 没有做多少工作。 本文提出了一个正式的图解分析多维度模型, 考虑基本图表数据数据, 以及背景信息以维度结构结构为形式。 这个模型的图表, 可以使用与其相关的不同层次来定义颗粒度。 与典型的 OLAP 模型相比, 典型的OL 类比典型的图解的图解模型支持了图解 。 本文展示了一个正式的LO AL 图表模型, 类比的模型的模型, 样的模型的模型的模型, MO AL 样的模型的模型的模型, 可以显示 MOAAP, 数据模型的模型的模型的模型的模型的模型, 。