Clarifying Normalization

Confusion exists among database textbooks as to the goal of normalization as well as to which normal form a designer should aspire. This article discusses such discrepancies with the intention of simplifying normalization for both teacher and student. This author’s industry and classroom experiences indicate such simplification yields quicker learning and more complete understanding by students

Relational databases: design and use

Relational databases: design and us

Issues and Guidelines in Modeling Decomposition of Minimum Participation in Entity-Relationship Diagrams

The entity-relationship model has long been employed for conceptual modeling of databases. Methodologies and heuristics have been developed, both for effective modeling and for translating entity-relationship models into relational models. One aspect of modeling that is often overlooked in design methodologies is the use of optional versus mandatory participation (i.e., minimum participation) on the development of relational databases. This tutorial complements existing instructional material on database design by analyzing the syntactic implications of minimum participation in binary, unary, and n-ary relationship sets and for the special case where the E-R diagram depicts a database where 3NF is not in BCNF. It then presents design modeling guidelines which demonstrate that (1) for binary 1:1 and 1:M relationship sets, the presence of optional participation sometimes means that the relationship set should be represented in the relational model by a separate relation, (2) unary relationship sets cannot have a (1,1) participation, (3) n-ary relationship sets that have a (1,1) participation can be simplified to be of lower connectivity, and (4) decomposition is not a substitute for normalization. Illustrative examples and modeling guidelines are provided

Family tree manager

Many people are interested in learning about their family history. Discovering who has come before us can help us learn more about who we are, and possibly why we are the way we are. Over the years, more and more people have turned to software products to help them build and manage their family tree information. These products allow users to easily enter and retrieve the information, as well as provide graphical representations without the arduous task of drawing by hand. In addition, some manufacturers have made agreements with genealogy search services, and integrated the process of searching for relatives into the software. A user can initiate a search for a family member at the same time he is entering information into the GUI. While this is certainly an important advancement, it appears that it has come at the expense of advancements in the user interface. The display of genealogy data is not a simple problem. Family tree information lends itself most to a sort of tree structure, but one in which there can be any number of levels, any number of elements per level, and any number of children per element. Making matters more difficult is the fact that a user really needs some way to visualize the structure and the content of the tree simultaneously. The main focus of this project is to develop a genealogy software product implemented in Java that makes use of a graphics toolkit to create a graphical view of family tree data that allows the user to visualize the content and structure of his family tree at the same time. This graphics toolkit will need to support user selection of graphical objects, panning, zooming, and animatio

DCPP/POLYGAIT Inventory Control System

This report discusses a proposed system to improve upon inventory management issues experienced in the M&TE Tool room for the PG&E Diablo Canyon Power plant. Effective inventory tracking and management is an important characteristic of any organization handling physical assets, and without the proper system in place, companies may lose expensive items and waste time by not having equipment available when needed. The tool room is experiencing inventory shrinkage of M&TE equipment nearing 100,000 per year largely because of an inefficient checkout system that fails to keep employees accountable for the tools they check out. Even more costly than the shrinkage of inventory is the expense of downtime incurred by not having a tool ready when needed. Two main issues with the current system were identified as the reasons for the shrinkage and lack of accountability: 1 when no tool clerk is on staff, mainly nights and weekends, an unreliable paper-method for checkout is used, and 2, employees are not held responsible for checking their tools back in, resulting in tools being handed-off outside of the tool room. To combat these problems, a self-checkout/check-in system was developed, eliminating the need for the paper system, requiring an employee login for returning tools, and reducing the total number of steps in the process by 36%. PG&E was also interested in using RFID (Radio Frequency Identification) technology to further increase accountability and improve the tracking of tools in and out of the tool room. A working proof-of-concept model was designed, built, and tested at Cal Poly’s POLYGAIT Laboratory along with recommendations for a potential implementation at PG&E. The results of the portal testing indicate that the best RFID tags for larger items include the Confidex Ironside Slim or Xerafy Cargo Trak tags while the Confidex Captura G2XM should be used for cabled probes. In addition, a maximum of six tools should be carried through the portal at a single time. An economic analysis for the proposed RFID system with revised checkout was performed along with two other alternatives: an increase in staffing on nights and weekends with the revised checkout and regular staffing with the revised checkout. All three alternatives were compared to the current state, which includes regular staffing without the revised checkout. The results of the economic analysis suggest that the RFID system paired with the revised checkout provides the lowest total cost solution, with a payback period of 0.046 years and a cumulative four-year return of 1,442,914.00. The second total lowest cost solution, which is the revised checkout method alone without an RFID system or increase in staffing, provides the fastest payback period of all the alternatives, in 0.019 years, but provides less of a return on an investment than when paired with the RFID system

Testing three hypotheses about effects of sensitive-insensitive parenting on telomeres.

Telomeres are the protective DNA-protein sequences appearing at the ends of chromosomes; they shorten with each cell division and are considered a biomarker of aging. Shorter telomere length and greater erosion have been associated with compromised physical and mental health and are hypothesized to be affected by early life stress. In the latter case, most work has relied on retrospective measures of early life stressors. The Dutch research (n = 193) presented herein tested 3 hypotheses prospectively regarding effects of sensitive-insensitive parenting during the first 2.5 years on telomere length at age 6, when first measured, and change over the following 4 years. It was predicted that (1) less sensitive parenting would predict shorter telomeres and greater erosion and that such effects would be most pronounced in children (2) exposed to prenatal stress and/or (3) who were highly negatively emotional as infants. Results revealed, only, that prenatal stress amplified parenting effects on telomere change-in a differential-susceptibility-related manner: Prenatally stressed children displayed more erosion when they experienced insensitive parenting and less erosion when they experienced sensitive parenting. Mechanisms that might initiate greater postnatal plasticity as a result of prenatal stress are highlighted and future work outlined. (PsycINFO Database Record (c) 2020 APA, all rights reserved)

A SQL front-end semantic data model

SQLSDM is a front end semantic data model to a SQL relational database management system (RDBMS). SQLSDM provides a more semantically complete RDBMS through the implementation of a Domain and Relational Integrity scheme. SQLSDM provides integrity definition functions and a sub-system to interpret SQL commands . Integrity system tables are created through the use of SQLSDM \u27 s domain definition command and SQL \u27 s CREATE TABLE command. As SQL database update commands are interpreted, SQLSDM uses these integrity tables to enforce domain and referential integrity. SQLSDM operates virtually transparent to the user and provides for greater database consistency and semantic control. Furthermore, SQLSDM is designed and engineered to be a portable front-end that may be implemented on any SQL relational database management system