Quiz 1.3 Flashcards
- What is the informal or general definition of a database?
Collection of related data (facts about the real world)
- Give a more formal definition of a database (include the three key implicit properties we discussed in class)?
- Logically Coherent.
- My database needs to have a purpose.
- Representative of the real world.
- What is a Database Management System (DBMS)?
Piece of software that helps us administrate our data.
- What four main actions does the Database Management System (DBMS) help us to facilitate in relation to the database (please complete the actions below as well as providing a short description)?
a. D – Define – data types, attribute names, entities (schema) in the database catalog (meta data).
b. C – Construct – file structures, disk, etc… how we represent our data (attributes make the majority of this).
c. M – Manipulate – Query, update, etc… on my database (modifying the state of the database). SQL – DML (Data Manipulation Language).
d. S – Need to make the database available to multiple users (multiuser vs. single user systems).
- What two other actions does the Database Management System (DBMS) help us facilitate in relation to the database (please complete the words below ?
a. P – Protection, implements RBAC (what is this?).
b. M – Maintain – apply updates to the DBMS software, indexing maintenance, etc…
- In the database approach, data types, constraints, and locations of the data are stored where?
Database Catalog (Meta data)
- This mechanism of storing data (see question 6) separately from the data types, constraints, and locations of the data facilitates this type of data independence or abstraction?
Program data independence.
- What are the two main properties of a transaction (give a short description of each)?
Isolation – as an end user, I need the system to appear as if I’m the only user.
Atomicity – shouldn’t have partial success in manipulation of my database (all pass, or all fail).
- What is the name for the combination of the primary database and secondary DBMS & related software?
The database system.
- The class of users who require access to the database for querying, updating, and generating reports to do their jobs?
End Users.
- Name three different types of users from the class of users described in question 10 (give a short description for each)?
- Casual (you know the rest)
- Naïve (Least about the database management system)
- Sophisticated (Most about the database management system)
o DBA (Database Admin)
Database Designer
Software Engineer
System Engineer, etc… - Standalone
- What are three benefits of using a Database Management System (DBMS) over a file-based system?
Control data redundancy – each user group might have same representation of student.
- Leads to data inconsistency.
- DOE (Duplication of Effort)
Security – implement more granular access i.e., RBAC, etc…
Ensure data abstraction – i.e., program data independence, method data independence.
- When might you choose to use a file based-based system over a Database Management System (DBMS)?
Single user system, overhead cost, short timeline.
- What law predicts that the number of transistors on a microchip will double every two years?
Moore’s law
- Describe the difference of horizontal and vertical scalability?
Vertical scalability increasing the storage medium space, ram, etc.., horizontal scalability – creating more instances of my databases programs (API).
- The module that typically handles user interaction and provides the user-friendly interfaces such as apps for mobile devices, or forms or menu-based GUIs (graphical user interfaces) for PCs.
Client Module
- The module that typically handles data storage, access, search, and other functions.
Server Module
- What is the suppression of details of data organization and storage referred to as (in general)?
Data abstraction
- What is the collection of concepts that can be used to describe the structure of a database referred to as?
Data Model
- What are the three types of general data models (name, and give a short description for each)?
Conceptual
Representational
Physical
- What are the three general components of the Conceptual Data Model (name and give a short description for each)?
Entities, attributes, relationships.
- This is referred to as the “description of the database”, is specified during database design, and is not expected to change frequently?
Database Schema
- What is the data in a database at a particular moment in time referred to as?
Database snapshot, database state
- What is the state of the database called that corresponds to when it satisfies the structure and constraints specified in the schema?
Valid state, business rules (business logic) – can’t be enforced by the DBMS.
- Changes occasionally need to be applied to the schema as the application requirements change, this is referred to as what?
Schema Evolution
- What are the three levels of the three-schema architecture (name, and give a short description for each)?
External
Conceptual
Physical
- What level of the three-schema architecture is the actual data stored at?
Physical
- What is the process of transforming requests and results between levels of the three-schema architecture?
Mapping
- What is data independence (in relation to the three-schema architecture)?
The ability to alter one level of the schema, without having to make changes to the other.
- Define the two types of data independence?
Logical data independence – Conceptual + External
Physical data independence – (Physical + (Conceptual + External)).
- Which type of data independence is harder to achieve and why?
Logical data independence – Conceptual + External
- The high-level DML (Data Manipulation Language) used in a standalone interactive manner is referred to as what?
Query language
- This type of language is used by the DBA and database designers to define the schema.
DDL (Data Definition Language)
