1.1: Traditional File Management vs Database Management Flashcards
Problems Of Early Data Processing
Redundancy, Inconsistency, Data-program dependence, Inflexibility
Data-program dependence (early data processing)
Strict data gathering by the application program, changes in data structure, will require changes in the program.
Redundancy (early data processing)
Repeated data, wasted memory, etc.
Inconsistency (early data processing)
Errors between data sets, since one can be updated by not another.
Inflexibility (early data processing)
Problematic to analyze data, since there’s several files that must have to be combined with high costs
Advantages of Database Systems
Data Independence, Efficient data access, Common data basis, Concurrent data access, Lacking or Controlled Redundancy, Consistency of Data, Integrity of Data
Data Independence (database systems)
Independent of application programs, no need to update program when data structure changes.
Efficient data access (database systems)
Index structures (allows quick access)
Common data basis (database systems)
since data is not repeated, it is updated correctly in the database. (avoids mismatch of data)
Concurrent data access (database systems)
Allows multiple users to access data. Concept of transaction for the synchronization of concurrent data accesses.
Lacking or Controlled Redundancy (database system)
avoids copies of same data, or controlled redundancy to improve performance.
Consistency of data (database system)
lacking redundancy, DBMS ensures consistency of data for controlled redundancy
INTEGRITY of data (database system)
Correctness and completeness of data. Formulation of integrity constraints or integrity rules. DBMS checks constraints for each insertion, change, and deletion of data
SECURITY of Data (database system)
Protection of unauthorized access (view on data). Access control, authentication and encoding are possible protection mechanisms.
Backup and Recovery (database system)
backup - copies of external storage media (e.g. tapes, discs)
recovery - automatic reconstruction of the last, up-to-date, and consistent database status with aids of tapes and listing the executed changes.