MIS 101 Ch 5-6

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MIS 101 Ch 5-6
2013-03-09 12:37:44
MIS 101

MIS 101 Ch 5-6
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  1. databases
    businesses of every size organize data records into collections called databases. Users have a crucial role in the development and the structure and content of the database. It depends entirely on how users view their business activity. Programmers build using an entity relationship model.
  2. Purpose of database
    to keep track of things.
  3. What is a database?
    a self describing collection of integrated records. bytes are grouped into columns such as student number and name. columns are called fields. columns and fields are grouped into rows which are called records. A group of similar rows or records is called a table or a file. The database is a collection of tables plus relationships among the rows in those tables, plus special data called metadata, that describes the structure of the database. The cylindrical symbol represents a computer disk drive.
  4. What are relationships among rows?
    A key is a column or group of columns that identifies a unique row in a table. A student number would be a key of the student table. Every table must have a key. Foreign keys is a term used because such columns are keys, but they ar ekeys of a different (foreign) table that the one in which they reside. Relational databases are data bases that carry their data in the form of tables and that represent relationships using foreign keys or a table is called a relation.
  5. Metadata pg 136
    The database itself contains, within in itself, a description of its contents. It is self describing. Databases are self describing because they contain data and data within in the data. Metadata are data that describe data.
  6. What are components of a database application system? 138
    they make database data more accessible and useful. Users employ a database application that consists of forms, formatted reports, queries and application programs. In turn, calls on the database management system (DBMS) to process the database tables .
  7. What is a database management system?
    A database management system (DBMS) is a program used to create, process, and administer a database. MySQL is an open source database that is license-free for most applications.
  8. Difference between DBMS and database. 138
    A DBMS is a software program; a database is a collection of tables, relationships, and metadata.
  9. Processing the database
    the second function of the DBMS is to process the database. Four operations: to read, insert, modify, or delete data. Uses SQL as the internation standard language for processing the database.
  10. Administering the database 142
    A third function is provide tools to assist in the administration of the database. Security, permissions, backing up the database, adding structures to improve the performance of the database applications, removing data that are no longer wanted or needed.
  11. How do database applications make databases more useful?
    A database application is a collection of forms, reports, queries, and application programs that process a database. A database may have more than one application.
  12. What are forms, reports, and queries?
    DBMS programs provide comprehensive and robust features for querying database data.
  13. Why are database applications programs needed?
    Application programs process logic that is specific to a given business need. The application program responds to events such as when a user presses a submit button; it also reads, inserts, modifies and deletes database data.
  14. Multi user processing
    Lost update problem, some type of locking must be used to coordinate the activities of users who know nothing about one another.
  15. Enterprise DBMS vs Personal DBMS 145
    DBMS products fall into two broad categories. Enterprise DBMS products process large organizational and workgroup databases. supports 1000s of users. Personal DMBS products are designed for smallers, simplere database applications for fewer than 100 users. Many have fewer than 15 or just 1 user. Access is the only remaining personal DBMS.
  16. How are data models used for database development? 146
    Data modeling and database design. User involvement is critical for the design development. Database structures can be complex, in some cases very complex. Developers develop a data model. It describes relationships that will be stored in the database. It is akin to a blueprint. Users requirements. Once user approves model, it is transfered to a database design. then into database structures.
  17. What is the Entity relationship data model?
    The entitiy relationship (E-R) data model is a tool for constructing data models. Developers use it to describe the content of a data model by defining the things (entities) that will be stored in the database and the relationships among those entities. A lessor popular tool for data modeling is the Unified Modeling Language (UML).
  18. Entities 147
    An entitiy is something that the users want to track. Ex order customer, sales person, and item. Some represent physical objects such as an item or sales person, others represent logical construct or transaction such as order or contract. Entities have attributes that describe characteristics of the entity. Order and order number. Entities have an identifier, which is an attribute (or a group of attributes) whose value is associated with one and only one entitiy instance. EX customer number of customer order. Sales person name is an identifier of a salesperson.
  19. Relationships 148
    Entities have relationships to each other. Database use entity relationship diagrams (E-R) to understand relationships. A line or mutiple lines  - crows feet is used to represent a relationship between entities. They are called 1:N or one to many relationships because one department may have many relationships. N:M mean that a variable number, greater than 1, is allowed on each side of the relationship. The maximum number of relationships are called maximum cardinality 1:M, N:M amd 1:1. Minimum is Minimum cardinality.  Oval means that the entity is optional, the relationship need not have an entitiy of that type.
  20. How is a data model transformed into a database design?
    database design transforms entities into tables and expresses relationships by defining foreign keys.
  21. Normalization 150
    Normalization is the process of converting a poorly structured table into two or more well structured tables.
  22. Data integrity problems
    A table of data integrity problems will produce incorrect and inconsistent info.
  23. Normalizing for data integrity 151
    The general goal of normalization is to construct tables such that every table has a single topic or theme. Database practitioners classify tables into various normal forms according to the kinds of problems they have. Transforming a table into a normal form to remove duplicated data and other problems is called normalizing the table. It could have a format that could cause data integrity problems.
  24. Summary of Normalization 152
    Every normalized (well formed) table has one and only one them. Tables that are not normalized are subject to data integrity problems.
  25. What is the Users' role in the development of databases?
    they are the final judges as to what data the database should contain and how the records in the database should be related to one another. Easiest time to change the database is during the data modeling stage. User review of the data model is crucial.
  26. 2021
    Data aggregators like Acxiom obtain data from public and private sources and store and process it in sophisticated ways.
  27. Immauel Kant, Data Modeler 161
    Resoned that what we perceive as reality is based on out perceptive appatatus. That which we perceive he called phenomena. Our perceptions such as of light and sound, are processed by our brains and made meaningful. noumenal and pheomenal world. 
  28. What is a computer network?
    A computer network is  a collection of computers that communicate withone another over transmissions lines or wirelessly. LAN local area network connects computers that reside in a single geographic location on the premises of the company that operates the LAN. The distinctive characteristic is that it is in a single location. A wide area network WAN connects computers at different geographic locations. An internet is a network of networks. Internets connect LANs, WANs, and other internets. Internet (capital I) private is little i. Private internet is an intranet. To provide seamless flow, an elaborate scheme called a layered protocol is used. Protocol is a set of rules that programs on two communicating devices flow.
  29. What are the componenets of a LAN? 171
    SOHO small business or a home office. fewer than a dozen computers and printers.
  30. Wired connectivity 172
    switch: which is a special purpose computer that recieves and transmits wired traffic on the LAN. The LAN device is a small computer that contains the following network components: switch (device for wireless communications, devices for connecting to a WAN and via the WAN to the Internet. Usually provided by the phone or cable provider. Network interface Card (NIC) which connects the computers device to implement the protocoles necessary for communication. Most computers have an onboard NIC, which is built into the computers circuitry. Most LAN connects are made using unshielded twisted pair (UTP) cable. The cable contains set of wires that are twisted together to improve signal quality. The UTP cable can be replaced by optical fiber cables. The signals on such cables are light rays, and they are reflected inside the glass core of the optical fiber cable.
  31. Wireless connections 172
    Wireless NIC (WNIC) instead of a NIC. Most computers now have an onboard WNIC. WNIC connects to an Access point, which is the component of the LAN device that processes wireless traffic and communicates with the wired switch.
  32. LAN Protocols
    two devices that connect must meet the same protocols. The IEEE 802. The IEEE 802.3 protocol is used for wired LAN connections called Ethernet which specifies hardware characteristics, such as which wire carries which signals. Wireless LAN uses IEEE 802.11 protocol. 802.11g popular. Bluetooth is another common wireless protocol. Short distances. mice and keyboards smartphone.
  33. What are the alternatives for connecting to a WAN?
    located at physically seperated sites. Internet service provider (ISP): three important functions, 1. provides you with a legitimate internet address, 2. it serves as your gateway to the Internet, ISPs pay for the internet.