DBMS FINAL MC

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jlm158
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DBMS FINAL MC
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2015-12-04 20:31:03
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DBMS FINAL MC
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  1. Data Structure
    Data are organized in the form of tables, with rows & columns
  2. Data manipulation
    Powerful operations (using SQL) are used to manipulate data stored in relations.
  3. Data integrity
    Mechanisms to specify business rules that maintain the integrity of the data when they are manipulated.
  4. Relation
    Named, two-dimensional table of data.
  5. Attribute
    Named column of a relation
  6. Record
    Row of relation that contains data values for a single entity.
  7. Primary Key (identifier)
    Attribute or combination of attributes that uniquely identifies each row in a relation.
  8. Composite Key
    Primary key that consists of more than one attribute
  9. Foreign Key
    Attribute (possibly composite) in a relation that serves as the primary key of another relation.
  10. Integrity Constraint - Domain Constraint
    All values in a column must be from the same domain.
  11. Domain
    Set of values that may be assigned to an attribute (name, meaning, data type, size/length, range of allowable values).
  12. Integrity Constraint - Entity Integrity
    Every relation has a primary key and the data values for the primary key are all valid. Every primary key attribute is non-null.
  13. Null
    Value that may be assigned to an attribute when no other value applies or when the applicable value is unknown. ABSENCE OF A VALUE. NOT THE SAME AS 0 or STRING OF BLANKS.
  14. Integrity Constraint - Referential Integrity
    Either each foreign key value must match a primary key value in another table relation or the foreign key value must be null.
  15. Well-structured Relation
    Contains minimal redundancy and allows users to insert, modify, delete rows without errors or inconsistencies.
  16. Anomaly
    Error that may result when a user attempts to update a table that contains redundant data.
  17. Regular Entity
    Entities that have independent existence and generally represent real world objects (persons, places, things).
  18. Weak entities
    Entities that cannot exist except with an identifying relationship as the owner (regular) entity type.
  19. Associate Entities (Gerunds)
    Formed from many to many relationships between entities
  20. Composite Attributes
    Must be broken up when creating relation (i.e. Address --> city, state, zip, etc.)
  21. Natural Primary Key
    key used in the organization and identified in conceptual data modeling as the identifier.

    KEY FORMED OF ATTRIBUTES THAT EXIST IN THE REAL WORLD (SSN #).
  22. Recursive Foreign Key
    Foreign key in a relation that references the primary key values of the same relation. Must have same domain as primary key (employee & supervisor unary).
  23. Normalization
    Process of successively reducing relations with anomalies to produce smaller, well-structured relations.

    Defines rules of business, not data use.
  24. Normal Form
    State of a relation that requires that certain rules regarding relationships between attributes (functional dependencies) are satisfied
  25. Functional Dependencies
    Constraint between two attributes in which the value of one attribute is determined by the value of another attribute

    A --> B

    If you know the value of A, there can only be ONE value for B.

    Act as constraints (i.e. if one then the other has to be)

    When you can always tell the one and only one value of another column given a single value.
  26. Determinant

    SSN, VIN, ISBN are determinants.

    A is determinant
    Left side of the arrow (A --> B)
  27. Candidate Key

    A candidate key is always a determinant, where as a determinant may or may not be a candidate key.

    CK can be determinant (not in violation)
    Attribute or composite that uniquely identifies a row in a relation. Multipass in example below.

    DU_NO (PK)    LNAME     MULTIPASS D1234            Malone     Malonej
  28. Merging - Synonym
    Two attributes that have different names but the same meaning (StudentID, CollegeID)
  29. Merging - Homonyms
    An attribute that may have more than one meaning.

    Account - may refer to a checking account, savings account, etc.
  30. Enterprise Key
    Primary key unique across the whole database, not just the table to which it applies.
  31. Business Key / Natural Key
    CUSTOMERID, EMPLOYEEID. Primary key that has business meaning.

    Can be Surrogate or Composite
  32. Database
    Organized collection of logically related data
  33. Structured Data
    Facts such as customer name, address. Numeric, character, dates. Stored in tabular form.
  34. Unstructured / Multimedia data
    Data such as documents, e-mails, maps, images, sound/video
  35. Information
    Data that has been processed in a way that increases knowledge.

    • Data in context (i.e. in a report)
    • Summarized data
  36. Metadata
    Data about data
  37. Metadata properties
    data names, definitions, length, allowable values.
  38. Metadata context
    Source of the data, where it is stored, stewards, usage.
  39. Program-Data Dependence
    File descriptions are stored within each database program that accesses a given file.

    Any change to a file structure requires changes to the file descriptions for all programs that access the file.
  40. Data Model
    Graphical systems used to capture the nature and relationships among data.
  41. Entity
    A person, a place, an object, an event, or a concept in the user environment about which the organization wishes to maintain data.
  42. Relational Database
    A database that represents data as a collection of tables in which all data relationships are represented by common values in related tables.
  43. DBMS
    Software that enables the use of a database approach. Provide a systematic method of creating, updating, storing, and retrieving the data stored in a database.
  44. Repository
    A centralized knowledge base of all data definitions, data relationships, screen and report formats, and other system components.
  45. CASE Tools
    Software tools that provide automated support for some portion of the systems development process.
  46. Two-Tier Client/Server DB
    Each member of the workgroup has a computer, and the computers are linked by means of network. In most cases, each computer has a copy of a specialized application (client) which provides the user interface. The database itself and the DBMS are stored on a central device Workgroup database called the “database server,” which is also connected to the network.
  47. Multitier Client/Server Databases
    User interface is accessible via Web browser using programming languages such as Visual Basic.NET.

    The application layer/Web server layer contains the business logic and talks to the database server.
  48. Data Warehouse
    An integrated decision support database whose content is derived from the various operational databases.
  49. ER Model
    Detailed, logical representation of the data for an organization or for a business area.
  50. Identifying owner
    entity type on which the weak entity type depends
  51. Identifying relationship
    The relationship between a weak entity type and its owner.
  52. Attribute
    A property or characteristic of an entity or relationship type that is of interest to the organization.
  53. Composite Attribute
    Attribute, such as Address, that has meaningful component parts, which are more detailed attributes
  54. Simple (Atomic) attribute
    Attribute that cannot be broken down into smaller components that are meaningful for the organization.
  55. Derived Attribute
    attribute whose values can be calculated from related attribute values
  56. Partial Specialization
    entity instance of the supertype is allowed not to belong to any subtype.

    Car and Truck are showing, not motorcycle (1 line)
  57. Total Specialization
    A rule that specifies that each entity instance of a supertype must be a member of some subtype in the relationship.

    Patient has to be either an outpatient or resident (2 lines)
  58. Disjoint (d)
    Patient cannot be both an outpatient or resident (one or the other, not both)
  59. Overlap (o)
    Part can be both manufactured and purchased
  60. Subtype discriminator
    An attribute of a supertype whose values determine the target subtype or subtypes.

    i.e. vehicle type (CAR vs. TRUCK)

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