...Proposed Purpose for the Database Huffman trucking utilizes this database to maintain and access important data about Huffman Trucking’s fleet vehicles such as vehicle and tire maintenance services, work orders, and unique vehicle identification information. Additional information that can be found in the database is vendor contact, parts inventory, and purchasing history. This database provides an efficient way to track and schedule routine maintenance, track parts inventory which helps prevent slowdowns in production. Parts Inventory Purchases Transaction ID Auto Number Primary Key Purchase Date Date/Time Purchase Price Currency Quantity Numeric Value Rationale of primary key – The Transaction ID should be a unique number which can be tracked back to the parts inventory purchase table and will make a perfect Primary Key. Rationale for foreign key 1 – There will be no foreign keys in this table as no other table for the Fleet Truck Maintenance will be using one of the values as a Primary Key. Rationale for foreign key 2 – There will be no foreign keys in this table as no other table for the Fleet Truck Maintenance will be using one of the values as a Primary Key Parts Inventory Issues Transaction ID Auto Number Foreign Key 1 Issue Date Date/Time Purchase Price Currency Quantity Numeric Value Parts Inventory ID Auto Number Primary Key Rationale of primary key – The parts inventory ID will be used as the primary key for the Parts inventory...
Words: 1514 - Pages: 7
...of the entity types, relationships, and constraints. The high-level data model is also used as a reference to ensure that all users’ data requirements are met and that the requirements do not include conflicts. 3.2 List the various cases where use of a null value would be appropriate? Null value would be appropriate when a particular entity does not have an applicable value for an attribute. There are two cases for such situations. The first case arises when it is known that the attribute value exists but is missing. An example for cases like such would be if the Height attribute of a person is listed as null. The second case arises when it is not known whether the attribute value exists. An example would be is the HomePhone attribute of a person is null. 3.3 Define the following terms: entity, attribute, attribute value, relationship instance, composite attribute, multivalued attribute, derived attribute, complex attribute, key attribute, value set (domain)? Entity Entity is a “thing” in the real world with an independent existence. It can also be an object with physical existence (i.e. person, car) or conceptual existence (i.e. company, job). Attribute An attribute is a particular property that describes entity (i.e. person name company name). Attribute Value Attribute values are major data stored in the database. Relationship Instance Relationship Instance is an association of entities, where the association includes exactly one entity from...
Words: 1644 - Pages: 7
...database system 2. Briefly describe the evolution of database systems and the limitations of conventional file processing systems 3. Describe the three schema architecture for database and explain the difference between conceptual , external and physical schemas 4. Define the functions of a database administrator Keywords and Phrases LEARNER Database Database System Entities Conceptual Model Logical Model Physical Model Constraints Metadata Database Management System File System Indexing Introduction This module introduces the reader to the different concepts of databases. It also tackles a brief history how automated databases came into existence. A number of advantages is discussed why the evolution of database management system is very much appreciated by system developers nowadays. 2 What is a Database ? Let us try to get the answers from the different Database Management System book authors. Answer from Pratt/Adamski: o A Database (DB) is structure that can store information about: 1. multiple types of entities, 2. the attributes that describe those entities; and 3. the relationships among the entities Answer from Elmasri/Navathe: o A Database (DB) is collection of related data - with the following properties: 1. A DB is logically coherent and has some relevant meaning 2. A DB is designed, built and populated with data for a specific purpose 3. A DB represents some aspect of the real world. Answer from Kroenke: An integrated, self-describing collection...
Words: 6349 - Pages: 26
...CIV E 603: Information Modeling and Database Systems Lecture 1 1 What to Study? Introduction to Data base Relational Model Database design Structured Query Language (SQL) 22 Let’s begin the journey !! …. in to fascinating world of databases 23 Today’s outline Database Management System (DBMS) Entity-Relationship (ER) Model 24 What is a database? Many people would like to call it organization… 25 What is a database? Database is a structured collection of related data. Many name it efficiency… 26 A database is A home for data – since that is where data stay… A manager for data – since data are organized neatly… A GOOGLE for data – since a particular record can be found in a snap… A guardian for data – since a database rejects malicious accesses… … 27 What is a Database? Database: is a collection of related data Data: known facts that can be recorded and that have implicit meaning Properties of database: • represents some aspect of the real world (mini-world -UoD) • logically coherent collection of data with some inherent meaning. A random assortment of data cannot correctly be referred to as a database. • designed, built, and populated with data for a specific purpose. It has an intended groups of users. 28 What is a Database? A database can be of any size and of varying complexity. • For example, the list of...
Words: 2400 - Pages: 10
...identifying the table elements. Upon analysis of the Entities and Attributes for Fleet Truck Maintenance form, the elements of the database tables can be identified. In a table, or relation, the entities and attributes of a table define the structure of a database. An entity is an object of importance about which data can be captured. An attribute is the information that describes the entity. When creating the tables for the Huffman Trucking Fleet Truck Maintenance, entities and their relationships must be taken into consideration (Koenke & Auer, 2010). Selection of Entities and Attributes In the Entities and Attributes for Fleet Truck Maintenance document, the entities and their attributes are clearly defined. The entities are listed in all capital letters. The entity’s respective attributes are listed below the entity. For example, for the entity “Parts_Inventory_Issues”, the attributes listed in the document are: • Transaction ID • Issue Date • Purchase Price • Quantity In creating the table, the attributes must be examined to ensure that the table is organized logically and contains no chances of redundancy. Because of this, the entities and attributes used in the actual database will be modified from the attributes listed in the document. Repeating attributes will be deleted or reorganized to ensure logical structure. Each table will contain a primary key. The creation of a table will have an added attribute; it will be the table’s primary key. For instance...
Words: 968 - Pages: 4
...E-R Model The Entity-Relationship (ER) Model Lecture Topics Basic ER modelling Extensions to ER modelling Designing an ER schema Reducing ER diagrams to relational schema 1 CS446/646 E-R Model Overview of ER Model Proposed by Peter Chen in 1976 Used for database (conceptual schema) design World/enterprise described in terms of entities attributes relationships Visualization: ER-diagram 2 CS446/646 E-R Model Basic ER Modelling Entity: a distinguishable object Entity set: set of entities of same type Ex. students currently at the Institute flights offered by Air Canada burglaries in Ontario during 1994 Graphical representation of entity sets: Student Flight Burglary 3 CS446/646 E-R Model Basic ER Modelling (cont’d) Attributes describe poperties of entities Domain: set of permitted values for an attribute Graphical representation of attributes Student Major StudentNum StudentName ¢¡ Ex. for Employee-entities: EmpNum, Name, Salary, 4 CS446/646 E-R Model Basic ER Modelling (cont’d) Relationship: representation of the fact that certain entities are related to each other Relationship set: set of relationships of a given type Ex. students registered in courses passengers booked on flights parents and their children bank branches, customers and their accounts In order for a relationship to exist, the participating entities must exist. ...
Words: 1337 - Pages: 6
...description of portion of database Database management system – a software application that is used to create, maintain, and provide controlled access to user databases Data independence – separation of data description Database – organized collection of related data Enterprise resource planning (ERP) – a business management system that integrates all functions of the enterprise Systems Development life cycle (SDLC) – a structured, step-by-step approach to systems development / The traditional methodology used to develop, maintain, and replace information systems Prototyping – a rapid approach to systems development Enterprise Data model – a graphical model that shows the high-level entities for the organization and the relationships among those entities Conceptual schema – a comprehensive...
Words: 1165 - Pages: 5
...Entity-Relationship Diagrams Georgia State University--CIS 850/330 Entity Relationship Modeling Entity-Relationship Diagrams Contents: Data Modeling User Views Entities/ Entity Sets Attributes Entity-Relationship Diagrams (ERDs) Finding Entities and Relationships English Grammar Rules Registration Example Student Registration Course Enrollment Grade Report Relationship Attributes Extended ERD Note: The Entity-Relationship Diagrams presented in this class are based on James Martin’s Information Enginnering approach. Georgia State University--CIS 850/330 Entity Relationship Modeling 1 Design Approach User View Collection of Tables 2. Normalize these relations Steps: 1. Model User View Collection of BCNF Tables 3. Represent all keys Collection of BCNF Tables with Keys Represented New Cumulative Design Old Cumulative Design Georgia State University--CIS 850/330 Entity Relationship Modeling 4. Merge the result of the previous steps into the cumulative design. Model User View Advantages of Data Modeling: + Data Analysis vs. Process Analysis + Graphical Models vs. Prose + “Data is more stable than processes.” Georgia State University--CIS 850/330 Entity Relationship Modeling 2 User Views A user view is the view of the data that is necessary to support the operations of a particular user. Example: Wells Junior College User View #1 -- Registration User View #2 -- Class Enrollment User View #2 -- Grade Reporting Georgia State University--CIS...
Words: 1334 - Pages: 6
...review the attached data model and answer the following questions. A. Entity: Entities are the building blocks of relational database design. An entity can be a real world object which exists actually or hypothetically has certain multiple attributes or properties which may be assigned values. An entity is a person, place, thing, event or conceptual object. An entity that will have many instances in the database. In given example Customer, booking, vehicle, Booking status, Vehicle category, Model, Manufacturer are entities. B. Attributes: Attribute is the characteristics or properties that an entity possesses. Attribute often corresponds to field in a table * Simple attribute − Each entity has a single value for the attribute, which cannot be partitioned further. For example customer_Id, booking_id, reg_Vehicle. * Composite attribute − Composite attributes are made of more than one simple attribute. For example, a customer complete name may have first_name, middle_name and last_name. * Derived attribute − Derived attributes are the attributes that do not exist in the physical database, but their values can be computed from other attributes present in the database. For example, age can be derived from date_of_birth. * Single-value attribute − Single-value attributes contain single value. For example –payment_received_yn. * Multi-value attribute − Multi-value attributes may contain more than one values. For example, a customer can have more than...
Words: 842 - Pages: 4
...................................................................... 5 1.1.1 Methodology .......................................................................................................................... 6 1.1.2 Data Modeling In the Context of Database Design................................................................ 6 1.1.3 Components of A Data Model................................................................................................ 6 1.1.4 Why is Data Modeling Important? ......................................................................................... 6 1.1.5 Summary ................................................................................................................................ 7 1.2 The Entity-Relationship Model ...................................................................................................... 7 1.2.1 Basic Constructs of E-R Modeling......................................................................................... 7 1.2.2...
Words: 16719 - Pages: 67
...1. What is an entity super type, and why is it used? It is an entity with 1 or more subtypes. It contains common characteristics. It is used to take advantage of inheritance, constraints, discriminators, and reduce the number of nulls. 2. What kinds of data would you store in an entity subtype? Entity subtypes contain more unique characteristics. A subtype will contain that data that is specific to the entity. Ex. A super type entity named Student contains a field for degrees studying but there could be multiple subtype entities for each different degrees and they would contain that which pertains to that certain degree. 3. What is a specialization hierarchy? It is an arrangement that has a super type entity that branches into one or more subtype or child entity. 4. What is a subtype discriminator? Give an example of its use. Attribute in the super type entity that determines to which subtype each super type occurrence is related. Subtype discriminator may be based on other comparison condition Flight Hours (>1,500 or <=1,500) 5. What is an overlapping subtype? Give an example. It is a subtype that contains non-unique subsets of the super type entity set. E.g. an employee can be both an Administrator and a teacher. 6. What is the difference between partial completeness and total completeness? Partial completeness is when a super-type does not need to use one of the subtypes, whereas total completeness must use at least one. Partial example: an...
Words: 1326 - Pages: 6
...(Database Design Using Entity-Relationship Diagrams) Checkpoint 1.1 1. Briefly describe the steps of the software engineering life-cycle process. a) Requirements – looking out what the user(client) needs and the problems b) Specification – make an analysis of the requirements. Find out the specifics needs c) Design – after you gather enough information, you design to meet the specification d) Developed – you star to write the software e) Tested – software is turned over to the user to be used in the application f) Maintenance – involves correcting hidden software faults as well as improving the functionality of the software. Checkpoint 1.3 1. What are functional dependencies? Give examples. A functional dependency is a relationship of one attribute or field in a record to another. For example, Social Security Number defines a name. This means that if I have a database with SSNs and names, and if I know someone’s SSN, then I can find their name. Another example would be the Employee’s number, if I know the EmpNo, and then I know the name. 2. What does the augmentative rule state? Give examples. Like the book explain, if. It means that you can add more information to the LHS of an FD and still have the FD be true. An example: If X is customer ID and Y is customer name and Z is birth date, then means that if you are given both a customer ID and a birth date, then it is possible to derive customer name and birth date from that. 3...
Words: 1206 - Pages: 5
... Entity relationship diagram (ERD) – a data model utilizing several notations to depict data in terms of the entities and relationships described by that data. 8 Data Modeling Concepts: Entity Entity a class of persons, places, objects, events, or concepts about which we need to capture and store data. –Named by a singular noun Persons: agency, contractor, customer, department, division, employee, instructor, student, supplier. Places: sales region, building, room, branch office, campus. Objects: book, machine, part, product, raw material, software license, software package, tool, vehicle model, vehicle. Events: application, award, cancellation, class, flight, invoice, order, registration, renewal, requisition, reservation, sale, trip. Concepts: account, block of time, bond, course, fund, qualification, stock. Data Modeling Concepts: Entity Entity instance – a single occurrence of an entity. 8-6 Student ID | Last Name | First Name | 2144 | Arnold | Betty | 3122 | Taylor | John | 3843 | Simmons | Lisa | 9844 | Macy | Bill | 2837 | Leath | Heather | 2293 | Wrench | Tim | Data Modeling Concepts: Attributes Attribute – a descriptive property or characteristic of an entity. Synonyms include element, property, and field. –Just as a physical student can have attributes, such as hair color, height, etc., data entity has data attributes Compound attribute – an attribute that consists of other attributes. Synonyms...
Words: 811 - Pages: 4
...that has three or more attributes. Let A, B, and C designate three distinct attributes (or distinct collections of attributes) in the relation. Suppose all three of the following conditions hold: 1. A → B 2. It is not the case that B → A 3. B → C Then the functional dependency A → C (which follows from 1 and 3 by the axiom of transitivity) is a transitive dependency. 2.1.3 Functional dependency is a relationship that exists when one attribute uniquely determines another...
Words: 1326 - Pages: 6
...description of the entity-relationship model and the use of this tool within the context of conceptual data modeling. This chapter presents the basic entity-relationship (or E-R) model, while advanced features are presented in Chapter 3. Chapter Objectives Specific student learning objectives are included in the beginning of the chapter. From an instructor’s point of view, the objectives of this chapter are to: 1. Emphasize the importance of understanding organizational data, and convince your students that unless they can represent data unambiguously in logical terms, they cannot implement a database that will effectively serve the needs of management. 2. Present the E-R model as a logical data model that can be used to capture the structure and much, although not all, of the semantics (or meaning) of data. 3. Apply E-R modeling concepts to several practical examples including the Pine Valley Furniture Company case. Key Terms |Associative entity |Entity-relationship diagram |Relationship instance | | |(E-R diagram) | | |Attribute | |Relationship type | |Binary relationship |Entity-relationship model |Required attribute ...
Words: 12988 - Pages: 52
