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CSE 511 Exam Questions And Accurate Answers (A+) Latest Update
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CSE 511 Exam Questions And AccurateAnswers (A+) Latest Update
What is data?
Devices that sense and monitor the environment ot collect data from the physical world.
2.8 Trillion sensor devices, 1.79 billion Facebook users, etc.
What is data processing?
The transition from data to information to extract knowledge from raw data.
What is big data (big data characteristics)?
1. The volume of available data is huge billions of devices interacting on a sec basis.
2. Data grows at an enormous rate (> 1 petabyte per day).
3. Data originates from multiple sources and in different formats.
What is scalable data processing?
Enable database processing systems to handle the volume, velocity and variety
dimensions that big data brings into the system
Name 3 data processing systems
Relational DBMS, NoSQL graph, Hadoop/Spark
Relational DBMS Centralsied, Distributed
Represents the world entities and objects using relations and tables. Operational
workload - bank, online store.
NoSQL
Uses non-table format data stores to work against unstructured data for highly available
systems.
,Hadoop/Spark
Doesn't work on operational or transactional workloads but focuses on analytics over
massive scale data.
What is a database?
A very large, integrated collection of data that uses entities (e.g. students, courses) and
relationships (e.g. Mike is taking CSE 511) to model real-world enterprise.
What is a Database Management System?
A system built on top of a database that allows
- Efficient data structures and algorithms to store data
- Applications on top of the data to retrieve data
- Manage and manipulate data (e.g. insert, update)
What are some key benefits of a DBMS?
- Data Independence: Isolates Dev/User from how data is managed & organized.
- Efficient Data Access: System relieves user burden of how to efficiently retrieve data.
- Data Integrity & Security: System takes care of how to secure the DB.
- Data Administration: Just 1 location where data is stored and 1 portal where data can
,be accessed.
-.Concurrent Access & Crash Recovery: Concurrently acces and run transactions
against the DB.
- Reduced App Development Time: Dev needs to focus only about the logic of the app
rather then scalability, efficiency, security.
Data Model
Collection of concepts, fundamental in DBMS, used for describing data. e.g relational
model table.
Schema
Description of a particular collection of data, using the given data model. E.g. {sid, age,
name, login}
Relational Model of Data
The most used data model, which relation is shown by a table with rows and columns. A
schema using the relational model is a description of the data using these tables.
Levels of Abstraction
Views/External Schemas -> Conceptual Schema -> Physical Schema -> Database
Physical Schema
Describes the way the data is organized and physically stored in the DB (the files,
sorting and indices used in the DB). Only 1 schema.
Conceptual (Logical) Schema
Conceptual schema defines the logical structure of the DB, how tables are set up, how
each entity is represented in the table. Only 1 schema can exist.
External Schema (Views)
Multiple exist on top of the conceptual schema. Views describe how users see the data.
, University Database Example Schemas
External Schema: Course_info creates view (for each course what is the total number of
enrollments) by integrating 2 tables.
- Conceptual Schema: Students, Courses, Enrolled
- Physical Schema: Relations stored as unordered files, Index on first column of
Students
What is one of the most important benefits of using a DBMS?
Data Independence - Isolates Dev/User from how data is managed & organized.
Logical Data Independence
Occurs at the conceptual schema level and protects the user/application from changes
in the logical structure of the data.
Physical Data Independence
shields the application from changes in the physical structure of data.
Example DBMS queries
What is the name of the student whose ID is 12?
What is the salary of Professor Sarwat?
This type of query is defined by an application developer.
Database Design Phases
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