Database Management Systems Chapter 1
Relational Model
All relational database DBMS products are built on this model -E.F. Codd applied the concepts of a branch of math called relational algebra to the problem of databases
Users
Final component of a database system, employ a database application to keep track of things -Use forms to read, enter, query data -produce reports to convey information
Surrogate Key
If the numbers used in primary key columns such as StudentNumber and ClassNumber are automatically generated and assigned in the database itself, then the key is also called the surrogate key
Data Warehouses and Data Marts
Store data specifically organized for research and reporting purposes, and these data are often exported to other analytical tools
SQL helps you produce information from a database
TRUE
SAP is the leading vendor of ERP applications
TRUE a key element of its product is a database that integrates data from various businesses.
Integrated Tables
Tables that store both data and the relationships among the data
e-commerce is an important database application
databases are a key component of e-commerce order entry, billing, shipping, and customer support
Applications that connect to the database over a corporate network
- These applications are called client/server applications because the application program is a client that connects to a database server. -Client/server applications are written in VB.NET, C++, Java
Referential Integrity Constraints
- With most DBMS products, it is possible to declare rules about data values and have a DBMS enforce them. -The rules are called this (RIC)
Database Migration
-A database is adapted to new or changing requirements -In the migration process, tables may be created, modified, or removed; relationships may be altered; data constraints may be changed
Oracle MySQL
-A powerful, open source DBMS frequently chosen for Web applicaitions
Enterprise-class database system
-Database applications in an enterprise-class database system introduce functions and features beyond the basics
The DBMS manages the database.
-It processes SQL statements and provides other features and functions for creating, processing, and administering the database
Information
-Knowledge derived from data -Data presented in a meaningful context -Data processed by summing, ordering, averaging, grouping, comparing, or other similar operations
Data Model
-The development team creates a data model from the requirements statements and then transforms that data model into a database design -A blueprint that is used as a design aid on the way to a database design, which is the basis for constructing the actual database in a DBMS product
A second category of applications is e-commerce and other applications that run of a Web server
-Users connect to such applications via Web browsers such as Internet Explorer. Common web servers include Microsofts Internet Information Server (IIS) and Apache -Common languages for web server applications include PHP, Java, Microsoft .NET languages such as c#.NET and VB.NET
Database System (2)
1. Users 2. The database application 3. SQL 4. The database management system (DBMS) 5. The database
Database Design (2)
1. process of designing a database 2. the annotated diagram that is the result of that process ......term is used both ways, watch out for the context
Concurrecny
A DBMS controls concurrency by ensuring that one user's work does not inappropriately interfere with another user's work
Self-describing
A database is self-describing because it contains a description of itself
Row
A row of a table has data about a particular instance or occurrence of the things of interest
Database Application
A set of one or more computer programs that serves as an intermediary between the user and the DBMS -Frequently written in house (can be acquired from software vendors) -Present data to users in the format of forms or reports
What do database professionals use?
A set of principles, collectively called normalization, or normal forms, to guide and assess database design
PrimaryKey
The values of these keys are used to create the relationships between the tables
Database Design
As a process, is the creation of the proper structure of database tables, the proper relationships between tables, appropriate data constraints, and other structural components of the database
Knowledge Worker
As a user, you prepare reports, mines data, and does other types of data analysis -users concerned with constructing SQL statements to get and put the data they want
Records
Because each row records the data for a specific instance, rows are also know as records
Database
Collection of related tables and other structures
Database Management System (DBMS)
Computer program used to create, process, and administer the database.
Metadata
Databases contain not only tables of user data, but also tables of data that describe that user data -data about data
Database System
Defined to consist of four components: 1. Users 2. The database application 3. The database management system (DBMS) 4. The database
Database Administrator
Designs, constructs, and manages the database itself -Concerned with the management of the database
Column
Each column of a table stores a characteristic common to all rows
The most popular data modeling technique
Entity-relationship (ER) data modeling
Structured Query Language (SQL)
Internationally recognized standard language that is understood by all commercial DBMS products, in database processing, and and the fact that database applications typically send SQL statements to the DBMS for for processing, we can refine our our illustration of a database system.
Personal Database System
Microsoft Access is not just a DBMS; it is a personal database system: a DBMS plus an application generator.
Foreign Key
Provides a link between two tables
Table
Rows and columns, like those in a spreadsheet
Relational Database
The purpose of a database is to help people keep track of things, and the most commonly used type of database is the relational database. -stores data in tables
Databases record facts and figures, so they record data.
They do so, however, in a way that produces information.
A database is a self-describing collection of integrated tables
True
Companies almost never write their own DBMS programs.
True
E-commerce companies use Web activity databases to determine which items on a Web page are popular and successful and which are not.
True
The DBMS receives requests encoded in SQL and translates those requests into actions on the database.
True
Programmer
Writes applications that process the database
Columns
also known as fields
A customer relationship management system (CRM)
an information system that manages customer contacts from initial solicitation through acceptance, purchase, continuing purchase, support, etc -used by sales managers, salespeople, customer service
Enterprise Resource Planning (ERP)
an information system that touches every department in a manufacturing company.
CODASYL DBTG
an unnecessarily complicated model
Data
recorded facts and numbers
What are the largest databases?
the ones that track are those that track customer browser behavior
Data Language/I (DL/I)
the way this program structured data relationships was by using hierarchies and trees
By adding a foreign key,
we create a relationship between the two tables
an example of e-commerce is
www.amazon.com and www.drugstore.com -They keep track of the web pages and the web page components that they send to their customers. they also track customer clicks. additions to shopping carts, order purchases, etc.