Chapter 5 In Class Notes Flashcards
Q1: What Is the Purpose of a Database?
• Organize and keep track of things • Keep track of multiple themes • General rule: – Single theme store in a spreadsheet – Multiple themes require a database
Q2: What Is a Database?
A self-describing collection of integrated
records
– Bytes are grouped into columns (a.k.a. fields)
– Columns are grouped into rows (a.k.a. records)
Rows in a database are also called
Records
Columns in a database are also called
fields
Characters in a database are also called
bytes
Bytes are grouped into
columns
Columns are grouped into
rows
Components of a Database. 3 things
Tables or Files + relationships among rows in tables + metadata = database
What Are Relationships Among Rows?
For example a student can be in the email table and also the student table. There’s a relationship among rows.
Key:
A column or group of columns that identifies a unique row in a table
Databases that carry their data in the form of tables
and that represent relationships using foreign keys
are called
relational databases
Metadata:
data that describes data
Q3: What Are the Components of a
Database Application System? 4 of them
- User
- Database Application
- Database management system
- Tables, Relationships, Metadata
Database Management System
A software program used to create, process, and administer a database
Database =
a collection of tables, relationships and metadata
The DBMS
• Three Functions
– Create tables, relationships, and other structures in the
database
– Process the database (using SQL or another processing
language)
• Read
• Insert
• Modify
• Delete data
– Provide tools to assist in the administration of the
database (e.g. security and optimization)
What are the 4 processes of a database
Read
Insert
Modify
Delete Data
Structured Query Language (SQL)
– International standard
– Used by most popular DBMS
Q4: How Do Database Applications
Make Databases More Useful?
A collection of forms, reports,
queries, and application programs that process a database.
• Provide process logic specific for a business need
• Enable processing via Internet
Q5: How Are Data Models Used for
Database Development? What is the process. 4 things
- You have the forms reports and queries with all the requirements.
- You then create a data model with entities and relationships
- Then you create database design with tables that have foreign keys
- Then you create the database
What Is the Entity-Relationship (E-R)
Data Model?
• Tool for constructing data models
• Describes contents of a data model by defining entities and
relationships among entities
• Unified Modeling Language (UML), less popular, tool for
data modeling
Q6: How Is a Data Model Transformed
into a Database Design?
- Construct Adviser table and Student tables with key
fields - Represent relationships by adding foreign keys
- Create new table for N:M relationships
Q7: What Is the Users’ Role in the
Development of Databases?
- Define what data database must contain
- Review data models for accuracy
- Final approval of data models
Q8: 2022?
• Relational databases will look much different
• Use of non-relational data stores, called NoSQL will
be more common
• Major DBMS vendors lose out to open-source
products and shift focus to services supporting open
source software like Bigtable, Dynamo, Cassandra?
• Database models will be very different
Popular DBMS products are?
DB2 from IBM. Access and SQL Server from Microsoft, and Oracle Database from the Oracle Corporation.
Give an example of a lost update problem.
When two people are shopping online and they both are buying the same thing at the same time. They both order it, but they only had one.
Enterprise DBMS
products process large organizational and workgroup databases.
Personal DBMS
products are designed for smaller, simpler database applications.
Logical representation of database data is called?
data model
entity
some thing that the users want to track. Examples are Order, customer, salesperson, and item.
describe characteristics of the entity. Examples are OrderNumber, OrderDate, SubTotal, Tax, Total
attributes
Identifier
attribute or group of attributes whose value is associated with one and only one entity instance
When you have a department entity and an advisor entity with a line going from the department to the advisor, what does it mean if the part of line touching the adviser is forked?
it’s a crow’s feet. Shows that a department may have more than one adviser.
Suppose for Adviser’s and Student’s the relationship line was forked on both sides. What would this mean?
Mean’s that an adviser can be related to many students and that a student can be related to many advisers
.Relationships like the ones on the previous question are called.
many-to-many relationships.
the process of converting a poorly structured table into two or more well-structured tables.
Normalization.
Data integrity problem example?
Some rows indicate that the name of department 100 is Accounting and Finance and some indicate that the department 100 is accounting
What does N:M look like?
crows feet on both sides
What does 1:N look like
Crows feet on one side
What does 1:1 say
one to one
What does 1:N say
One to Many
what does N:M say
Many to Many
Maximum Cardinality
The maximum number of
entities that can be involved in a relationship
Minimum Cardinality
The minimum requirements
