Designing a Low-Code CRUD framework

Nowadays programmers write source code for inserting, editing and deleting records of a relational table. The majority of commercial relational databases include a specific management tool that offers such possibilities and most database programmers take this ability as granted. When it comes to real life applications, programmers use Object Oriented (OO) paradigm to build user friendly windows/screens/forms for database operations. The current work shows a different approach using a Low-code CRUD (Create, Read, Update, Delete) framework. Views and guidelines of how to design a Low-code CRUD framework will be detailed. “Low-code” motivation is due to the fact that the new framework will provide the ability to use less code in order to build fast and efficient complex applications. It will be up to the reader to envision a specific framework.

Learned cardinality estimation

Cardinality estimation is core to the query optimizers of DBMSs. Non-learned methods, especially based on histograms and samplings, have been widely used in commercial and open-source DBMSs. Nevertheless, histograms and samplings can only be used to summarize one or few columns, which fall short of capturing the joint data distribution over an arbitrary combination of columns, because of the oversimplification of histograms and samplings over the original relational table(s). Consequently, these traditional methods typically make bad predictions for hard cases such as queries over multiple columns, with multiple predicates, and joins between multiple tables. Recently, learned cardinality estimators have been widely studied. Because these learned estimators can better capture the data distribution and query characteristics, empowered by the recent advance of (deep learning) models, they outperform non-learned methods on many cases. The goals of this paper are to provide a design space exploration of learned cardinality estimators and to have a comprehensive comparison of the SOTA learned approaches so as to provide a guidance for practitioners to decide what method to use under various practical scenarios.

Efficient distributed discovery of bidirectional order dependencies

Bidirectional order dependencies (bODs) capture order relationships between lists of attributes in a relational table. They can express that, for example, sorting books by publication date in ascending order also sorts them by age in descending order. The knowledge about order relationships is useful for many data management tasks, such as query optimization, data cleaning, or consistency checking. Because the bODs of a specific dataset are usually not explicitly given, they need to be discovered. The discovery of all minimal bODs (in set-based canonical form) is a task with exponential complexity in the number of attributes, though, which is why existing bOD discovery algorithms cannot process datasets of practically relevant size in a reasonable time. In this paper, we propose the distributed bOD discovery algorithm DISTOD, whose execution time scales with the available hardware. DISTOD is a scalable, robust, and elastic bOD discovery approach that combines efficient pruning techniques for bOD candidates in set-based canonical form with a novel, reactive, and distributed search strategy. Our evaluation on various datasets shows that DISTOD outperforms both single-threaded and distributed state-of-the-art bOD discovery algorithms by up to orders of magnitude; it can, in particular, process much larger datasets.

Hoist Sheave Structure Optimization and Lightweight

To ensure wheel body of the hoisting sheave strength and stability condition. For the purpose of wheel body lightweighting. There are two schemes to reduce body weight.Reduce the spokes at the same time increase the ring stiffened plate, and reduce the spokes at the same time change the spokes width and thickness.The wheel body was established based on Pro/E 3D geometric model. Import the mesh in the Workbench of ANSYS software for finite element model. Statics analysis to select the optimized scheme. Establish a hoisting sheave wheel body under the actual working condition of widening the width - deformation - wheel weight relational table. Analysis to lightweight at the same time ensure that stiffness of wheel,then it can obtaine the optimal result.

A New Storage Design of Distributed Geographic Information

In order to solve the storage problem of mass graphic data in web, an improved hierarchy of graphic objects is used in this paper. By building up layer object, the system can manage the data for different levels of abstraction. It is different from Object-Oriented Data Base (OODB) which used a relational table as an object to manage data. Uniform operations for the same terrain are offered. Using Object-based Storage Device (OSD) is advantaged at data transmission. The method of storing layer object in OSD is given in the paper. Empirical results show that the mechanism is well-suited to fetch detail data in web.

Minimal Query Algorithm of XML Document Based on Unconstrained Tree Pattern

XML document structure uses the tree structure to express the document structure model that is different from the traditional two-dimensional relational table structure and XML query patterns mainly for tree query. Tree pattern always divided into constrained type and unconstrained type. This paper based on unconstrained tree pattern query, provide a mini algorithm of unconstrained tree pattern query, and prove the correctness of algorithm theoretically.

A Parallel Implementation Scheme of Relational Tables Based on Multidimensional Extendible Array

In this article, an efficient parallel implementation scheme of relational tables is proposed and evaluated. The scheme implements a relational table by employing an extendible multidimensional array. Data allocation is a key performance factor for parallel database systems. This holds especially for data warehousing environments in which huge amounts of data have to be dealt with. In our scheme, an efficient data allocation technique is used, based on the notion of extendible array. The dynamic load balancing is conducted when load on each processor is not uniformly distributed in order to maximize processor utilization.