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CPSC 3660 - Intro and concepts

  1. Database
    • Collection of data
    • Relevant to some word entity
    • No irrelevant data included
    • Interrelated
  2. World entity
    • Something that exists in the real world.
    • e.g Student
    • e.g Employee
    • e.g Car
  3. Database management system
    • Software/language for data access and manipulation
    • A.k.a DBMS
  4. List some problems with traditional file processing
    • Redundancy
    • Inconsistency
    • Data isolation
    • Lack of data integrity
    • Lack of atomicity
    • Concurrent access isues
  5. How are database management systems different from traditional file processing?
    • DBMS use abstraction
    • Details of the data are hidden from the user and programs
  6. Goal of a database management system
    Physical data independence
  7. Levels of data abstraction
    • View level
    • Logical level
    • Physical level
  8. Schema
    A description of the database design
  9. Instance
    The actual data in the database at a given time
  10. Data model
    A model for describing a database
  11. What are some elements of data models?
    • Data
    • Semantics (how it's organized)
    • Relationships
    • Consistency constraints
  12. Examples of data models
    • Entity-relationship
    • Relational
    • Object-oriented
    • Semi-structured (XML)
  13. Database languages
    • Data definition language
    • Data manipulation language
  14. What does data definition language do/what is it used for?
    • Defines schemas
    • Defining constraints
  15. Examples of data definition constraints
    • Domain constraints
    • Referential integrity constraints
    • Assertions
    • Authorization constraints
  16. Data definitions are also known as
    Metadata
  17. Where are data definitions stored?
    In a data dictionary
  18. What is data manipulation language used for?
    • Retrieval of information
    • Modification of information
  19. What is a domain violation?
    Using a value that is not in the specified domain
  20. What is a referential integrity violation?
    A reference to a record that does not exist in the system
  21. What is a primary key violation?
    Duplicate primary keys (they have to be unique)
  22. A mandatory field is also known as
    Not null
  23. The four components of a database management system?
    • Users
    • Query Processor
    • Storage manager
    • Data storage
  24. Elements of the data storage component of a DBMS
    • Data
    • Data dictionary
    • Indices
    • Statistical data
  25. Components of the storage manager component of a DBMS
    • File manager
    • Buffer manager
    • Authorization and integrity manager
    • Transaction manager
  26. What does ACID stand for?
    • Atomicity
    • Consistency
    • Isolation
    • Durability
  27. What is the transaction manager's jobs?
    • Correct execution of transaction (according to ACID)
    • Failure recovery
    • Concurrency control
  28. Components of the query processor component of a DBMS
    • DDL interpreter
    • DML compiler
    • Query evaluation engine
  29. Types of DBMS user
    • Naive users
    • Sophisticated users
    • Application programmers
    • Database administrators
  30. What is data isolation (traditional file processing)?
    • When data in separate files, that should be related, isn't recorded/updated correctly
    • Requires extra effort to prevent and handle
  31. Atomicity
    The guarantee that a series of operations will either all occur, or none will occur
  32. Physical data level
    How data is organized on disk
  33. Logical data level
    • How data as a whole is viewed for access
    • No physical level details
  34. View data level
    Logical view of subset data
  35. Domain constraint
    A set of legal values
  36. Referential integrity constraint
    Ensures an identifier must exist in another table
  37. Example of an assertion (constraint)
    Specifying that an identifier is unique
  38. Authorization constraint
    Who has access to what
  39. What are some things that are stored in a data dictionary
    • Definitions
    • Number of records, distinct values of fields
  40. Alternate word for retrieval
    Query
  41. Retrievals (examples) that modify the data
    • INSERT
    • DELETE
    • UPDATE
  42. Declarative language
    • Language that the user uses to specify what they want
    • No way to tell the database how to do what it does
  43. Procedural language
    • Specifies how the database should fetch data
    • Specifies how the database should select records
    • Specifies how to relate tables (JOIN)
    • Internally process declarative queries
  44. Example of a procedural language
    Relational algebra
  45. Role of the file manager
    How data is physically organized and stored
  46. Role of the buffer manager
    • A buffer that stores a certain number of items from the database
    • Decides what should be buffered and what shouldn't
    • Similar to a cache
  47. Role of the authorization integrity manager
    • Ensures that the user has permission to access what they're trying to
    • Ensures actions/queries meet given constraints
  48. Roles of the transaction manager
    • Ensuring Atomicity
    • Handling concurrency
    • Recovery
  49. What does the data manipulation language (DML) compiler do?
    Forms a relational algebra statement from a query
  50. What does the query evaluation engine do?
    Takes the internal form of a query and attempts to find the most efficient way to evaluate it
  51. Naive user
    User that (for example) accesses the webpage
  52. Sophisticated user
    Writes SQL queries
  53. Application programmer
    • Write programs that embed SQL queries
    • E.g they write web pages or web apps
  54. Database administrators
    • Have all the database privileges
    • Lowest level
Author
Ant
ID
356613
Card Set
CPSC 3660 - Intro and concepts
Description
Updated

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