Relational schema activation: Does Bob Zajonc ever scowl at you from the back of your mind?

Author(s):  
Mark W. Baldwin
2019 ◽  
Author(s):  
Atefe Abdolmanafi ◽  
Sam Winter ◽  
Reza Ghorban Jahromi ◽  
Hojatollah Farahani ◽  
Maria Manuela Peixoto ◽  
...  

2021 ◽  
Vol 17 (4) ◽  
pp. 1-28
Author(s):  
Waqas Ahmed ◽  
Esteban Zimányi ◽  
Alejandro A. Vaisman ◽  
Robert Wrembel

Data warehouses (DWs) evolve in both their content and schema due to changes of user requirements, business processes, or external sources to name a few. Although multiple approaches using temporal and/or multiversion DWs have been proposed to handle these changes, an efficient solution for this problem is still lacking. The authors' approach is to separate concerns and use temporal DWs to deal with content changes, and multiversion DWs to deal with schema changes. To address the former, previously, they have proposed a temporal multidimensional (MD) model. In this paper, they propose a multiversion MD model for schema evolution to tackle the latter problem. The two models complement each other and allow managing both content and schema evolution. In this paper, the semantics of schema modification operators (SMOs) to derive various schema versions are given. It is also shown how online analytical processing (OLAP) operations like roll-up work on the model. Finally, the mapping from the multiversion MD model to a relational schema is given along with OLAP operations in standard SQL.


2019 ◽  
Vol 6 (1) ◽  
pp. 20
Author(s):  
Etika Ariyani ◽  
Etika Ariyani

Reading is one of the important skills that the students have to master. However, many students have difficulties in comprehending the reading text. To solve this condition, the researcher used schema activation strategy to help students understand reading comprehension. The purpose of this research was to investigate whether the use of schema activation strategy is effective or not in teaching reading comprehension at the second-grade students of MTs Tarbiyatul Mustafid in academic year 2017/2018. This study was quasi-experimental design using two classes were VIII B class was taken as an experimental class, and VII-A was taken as control class. The population of this research involved 60 students from the second grade in MTs Tarbiyatul Mustafid Batu Simpang. By using purposive sampling, the researcher took the students as a sample. In collecting the data, this study used pre-test, treatment, and post-test as the data collection procedure then followed by analyzing the data by using the t-test formula. Then the result of statistical analysis of t-test in this research was 2.85. It was higher than critical values for t- table in the degree of freedom (df) of 58 is 2.021(0.05%) and 2.704(0.01%). The researcher concludes that mean score before and after teaching by using schema activation strategy has a difference. It means the alternative hypothesis (ha) was accepted. The use of schema activation strategy in teaching reading comprehension at the second-grade students of MTs Tarbiyatul Mustafid Batu Rimpang is effective.


Author(s):  
Wei Lijun ◽  
Pan Yang ◽  
Wang Hao ◽  
Wang Xianchao ◽  
Zhang Yan

To make up for the defects of semanteme expression about linked data, this paper proposes a semanteme expressing method of associated entities based on relationship diagram so as to realize the machine expression and recognition of associated semanteme in relational databases. Starting with the structure and relationship of relational schema, this paper analyzes the rich semanteme of associated entities and presents the semanteme parsing method based on the traversal path as well as its formal expression; the analysis of instance database is also carried out. Studies show that this method can comprehensively parse and express the associated semanteme of entities. This work has reference significance for the research of intelligent semanteme synthesis and for semanteme-oriented intelligent query.


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