Download Topics Database Essential Concepts What`s a Good Database

Topics
Databases
Database Essential Concepts

Software V: Databases. Database concepts:
records, fields, data types. Relational and objectoriented databases.
Database
 collection of information stored
Database
in an organized way
 can consist of one or more files
Computer maintenance and operation: storage
health and utilities; back-up strategies; keeping
files and folders organized; virus checkers; etc.

Database file (Table)

Records

Field
Files
 made up of records
 organized into distinct fields
 separate area to store a certain
type of information
Table
Record
Fields
What’
What’s a Good Database
System?
Databases
Databases
Using Database Software


Data integrity
Finding information
browse view
list view
queries
Structured Query Language (SQL)
use data validation procedures
Data independence: do not use
proprietary data coding
 Avoidance of data redundancy
 Data security
 Data maintenance

Learn SQL online at “Introduction to Structured Query
Language,” an online tutorial.
Databases
Using Database Software
Reports can be
viewed on screen or
printed
Databases
Types of Database Programs

File management programs

Database management systems (DBMS)
flat files (e.g. Excel documents)
relational database (Access) where tables are
related by key fields
object-oriented databases (elements in

records are objects like whole files instead of
pieces of information)
Printing the data
reports
form letters
report languages

Data warehousing & data mining
Warehouse: primitive data from all depts.
Mining: detection of patterns in data by
statistical means
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MS Access is a Relational
Database Management System.
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Suppose you have a shop and you want to make
some kind of database to store information about
your products, your clients, and the orders they
place...
Flat database system:
 Create two tables: one with the information about your
products and what is ordered and one with the
information about your clients and their orders.
 The problem is that after some time, your tables will
contain duplicate information; each order a client places
needs to have his information repeated.
Referential Integrity
Relational Database
Management System:


Put data about different types
of entities in separate tables to
avoid duplication and define
relationships between the
tables so that you still can get
all the information.
If you want to work relational
then data must comply with
the rules to be relational.
 Avoid redundant data
 Ensure referential integrity
1. What are the
entities you want
to describe?
2. How many kinds
of entities do you
have?
People,
products,
Orders.
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3. How will you
describe them?
Name, address, …
Name, color, size, …
Who, what, when …
4. How will you
identify them?
Key field
Relational Database Structure
Rules that apply to the relationships between
tables in a RDBMS.
 For example, take two related tables, A and B:

What happens to the record(s) in table B if the
record to which it is related, is deleted from table A?
Or if one tries to add a record to table B that
cannot be linked to table A?
Or if you update the value of a linked field in table
A, will the linked records from table B be modified
accordingly?
Access window elements
Access button functions
2
Access objects: tab view
Definition of Access objects
Creating a Database
Database data types
Modifying Table: Design
Fields, data types & descriptions
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Editing Table
Finding information in Table
Results of FIND are not saved
Using more complex Filters
Removing Filters
Queries can be saved
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Using Forms to enter and display information
Example of a Form
Using Form Wizard
Use Reports to create output
Using the Report Wizard
Example of a Report
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Normalization
1. All data must be atomic. Each record has a
UNIQUE ID. Eg: first and last names,
address components
 2. Blocks of data with repeated information
that applies to several records should be
broken up in to two or more additional tables,
linked by means of a FOREIGN KEY. An
attribute that completes a relationship with a
parent entity.
 3. Tables should only have columns that are
fully dependent on the primary key.
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