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.
Posing QUERIES (database system)
Query language, allows, to pose queries to get an immediate answer
Queries can be pose ad hoc (keyboard), embedded into database application programs. Importance of query optimization, query processing, and query execution.
Provision of diversified USER INTERFACES (database system)
query languages for occasional users, programming interfaces for implementers, etc.
Database (DB)
Structured storage of large collections of persistent data, reliable basis of up-to-date information.
Database Management System (DBMS)
All-purpose software system. Allows user to build and manipulate databases in an efficient manner. Software level between physical database and user.
Database System (DBS)
DBS = DBMS + DB
The Database Management System in addition of Database
Meta Data (Stored database definitions)
Data about the data. ex. For a student we will store (first name, last name, DOB, etc)
Structure of a database
Raw Data (Stored database definitions)
The actual data. (Carlos, 18, Student)
Data Model
Description of structure of a database (data types, relationships, conditions) alongside operations for handling and manipulating the data.
Data Model Offers:
specs of data objects
specs of relationships between data
specs of operations on data objects
DBS has at least 2 data models:
Physical, and Logical (data models)
Physical data model
storage-oriented representation of data.
Logical data model
user-oriented representation of data.
Types of Logical data models
Object-based & Record-based
Name 3 object based (logical) models
Entity-Relationship Model
Object-Oriented Data Model
Object-Relational Data Model (object & record)
Name 4 record-based (logical) models
Object-Relational Model (object & record)
Relational Data Model
Network Data Model
Hierarchical data model
Select all disadvantages of file systems found in the following list:
* Inflexibility
* Redundancy
* Data-program independence
* Consistency
Inflexibility
Redundancy
Select all ADVANTAGES of database systems found in the following list:
* Efficient data access
* Concurrent data access
* Data independence
* Integrity of data
* Common data basis
- Efficient data access
- Concurrent data access
- Data independence
- Integrity of data
- Common data basis
A data definition language allows the user to:
A) Define and change the structure of a database.
B) Design the structure of a database.
C) No answer text provided.
D) Manipulate the data in a database.
A) Define and change the structure of a database.
A query allows the user to pose ad hoc queries by using the keyboard and get an immediate answer
(True or False)
TRUE
Which statements are correct? A database management system is:
* A set of programs for the management of and access to the data in the database.
* An all-purpose software system, which supports the user in the definition, construction and manipulation of databases for different applications in an application-neutral and efficient manner.
* A hardware level between the physical database and the user.
* A repository of data.
- A set of programs for the management of and access to the data in the database.
- An all-purpose software system, which supports the user in the definition, construction and manipulation of databases for different applications in an application-neutral and efficient manner.
Which statements are correct? Metadata:
- Mean “data about data”
- Describe the operations of a database system.
- Are data about the definition of the structure of a database.
- Mean “data about data”
- Are data about the definition of the structure of a database.
The user-oriented representation of data is provided by the:
A) Logical Data Model
B) Physical Data Model
A) Logical Data Model
What type of data model is a relational data model?
A record-based data model
