22 Questions
What is the primary function of the intermediate layer in a three-tier client-server architecture?
Stores the web connectivity software and the business logic
SQL is a procedural language.
False
What does SQL stand for?
Structured Query Language
In a three-tier client-server architecture, the database server is only accessible via a _______________ tier.
middle
What is the main benefit of a three-tier client-server architecture in terms of security?
Increased security
Match the SQL language components with their functions:
DDL = Data definition DML = Data manipulation TCL = Transaction control DCL = Data control and security
Clients can directly access a database server in a three-tier client-server architecture.
False
What is the main focus of SQL?
Data and results
What is the primary function of an index in a database?
To improve the performance of some queries
A synonym is used to generate primary key values in a database.
False
What is the basic unit of storage in a database?
Table
A view is a virtual table that logically represents subsets of data from one or more _______
tables
What is the purpose of keeping track of the dependents of each employee in the COMPANY database?
For insurance purposes
The COMPANY database keeps track of the start date when an employee began managing the department.
True
Match the following database objects with their descriptions:
Table = Basic unit of storage View = Logically represents subsets of data from one or more tables Sequence = Generates primary key values Index = Improves the performance of some queries
What is the purpose of a sequence in a database?
To generate primary key values
What is a Database Management System (DBMS)?
A software package to facilitate the creation and maintenance of a computerized database
A database system includes only the DBMS software and the data itself.
False
What is a database?
A collection of related data.
The DBMS software together with the data itself is called a _________________ system.
database
Match the following terms with their definitions:
Database = A collection of related data Data = Known facts that can be recorded and have an implicit meaning DBMS = A software package to facilitate the creation and maintenance of a computerized database Database System = The DBMS software together with the data itself
What is an example of a DBMS?
All of the above
Study Notes
Database Security
- A database is a collection of related data.
- Data refers to known facts that can be recorded and have an implicit meaning.
- A Database Management System (DBMS) is a software package/system to facilitate the creation and maintenance of a computerized database.
Database System Environment
- A Database System consists of the DBMS software together with the data itself, and sometimes includes applications.
- Example: a student information system (SIS).
- Three-Tier Client-Server Architecture is common for web applications, and can enhance security by:
- Only allowing database server access via a middle tier
- Preventing clients from directly accessing a database server
- Clients contain user interfaces and web browsers, and are typically PCs or mobile devices connected to the web
DBMS Architectures
- Two types of Client-Server Architectures:
- Two-Tier Client-Server Architecture
- Three-Tier Client-Server Architecture
Basic SQL
- SQL is non-procedural, meaning users specify what data is to be retrieved rather than how to retrieve it.
- SQL stands for Structured Query Language and is pronounced as "sequel".
- SQL allows users to access data in relational database management systems.
- SQL has four components:
- Data Definition Language (DDL)
- Data Manipulation Language (DML)
- Transaction Control Language (TCL)
- Data Control Language (DCL)
Database Objects
- Table: the basic unit of storage, composed of rows and columns.
- View: logically represents subsets of data from one or more tables.
- Sequence: generates primary key values.
- Index: improves the performance of some queries.
- Synonym: gives alternative names to objects.
Database Design Process
- Overview of the database design process involves several stages.
Example COMPANY Database
- The COMPANY database application keeps track of:
- A company's employees
- The department each employee manages
- The start date when an employee began managing a department
- The number of hours per week an employee works on each project
- The direct supervisor of each employee
- The dependents of each employee for insurance purposes
- Each dependent's first name, sex, birth date, and relationship with the employee
Learn the basics of databases, including data definition, database management systems, and database system environments. Understand the role of DBMS software and its applications.
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