Relational Database Software

Microsoft Access 2000

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Note before we begin: Converting a database You CAN convert Access 95, 97

directly to 2000 You CANNOT convert Access 2000

directly to 95 or 97 Save it down > Tools/Database

Utilities/Convert Database/to Prior Access Version

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General Concepts

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What is a Database and what is it used for?

A database is an organized collection of data related to a particular topic or purpose.

The primary function of a database is to enable the user to organize and retrieve information in a manner defined by the user.

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Access Relational database software with a

graphical user interface. Access integrates easily with Excel

& Word. Easy to get started with pre-made

tables, forms, queries & reports. Can use to create database

applications by incorporating macros & modules (Visual Basic).

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A Flat-file database consists of a single database file or table which contains all the information about a topic. It does not physically link or point to other files.

A Relational database consists of multiple tables linked together by at least one common field.

Flat-File vs. Relational

Name Address ClassID ClassName Instructor Time

Mary Wills 1010 1st St. CO150 Composition Matthews 3 MWF

Jim Johnson 234 Maple CO150 Composition Matthews 3 MWF

Mark Smith 111 W. 3rd CO150 Composition Matthews 3 MWF

STUDENT INFORMATION TABLE

ProdID ProductName UnitPrice Quantity SupplierID 1234 Cajun Seasoning $1.00 2000 S450

SupplierID SupplierName Address Contact Phone

S450 New OrleansDelights

NewOrleans,LA

Anne Rice 800-555-1111

Supplier Table

Products Table

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The Database window Menus and toolbars Command Center – all operations

start here Categories of objects on left Objects and creation icons on right Status bar

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Access Database Objects Tables Forms Reports Queries Macros Modules Pages

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Tables Tables are the heart of Access. All data stored in tables. Fields (columns)

and records (rows) intersect to form cells. Each table should contain information

about one subject only. Each field contains a specific type of

information such as text, number, currency, dates, etc.

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Tables (cont.)

Two or more tables are linked together through fields they have in common. This is done by defining relationships.

Access creates relationships between different tables, about different but related subjects

A table should contain data about 1 topic only, e.g., not students and faculty in one.

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Queries Create a subset (dynaset) of data. Means for obtaining data from 1 or

more related tables. Used to sort and/or select records

according to your criteria. Used as the basis for reports. Action queries can be used to

update, archive, delete, append records, etc.

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Forms Used to view, edit, and enter data. You

can also enter data directly into a table. They can be customized for convenience. Best for on-screen viewing.

Forms may be designed to simplify data entry and data editing.

Can use controls to make data entry easier and more consistent such as drop-down lists, radio buttons, etc.

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Reports Sorted and summarized data. They can

be designed to show only the data you want to show. Best for printed materials.

Used for printing data in an organized, professional looking manner.

Can add subtotals, groupings, etc. to reports.

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Macros Automatically carry out one or more

tasks. Best for tasks that you perform often.

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Modules A set of procedures stored as a unit

to perform an action. Written in Visual Basic.

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Pages A data access page for viewing on

the Internet, or an intranet.

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Table Design vs. Table datasheet view Toggle in the upper right corner. Flips

between the data itself (table) and the underlying structure (design) of the data.

Datasheet allows you to enter data, sort and filter data, hide and freeze columns, etc.

Design allows you to create tables, add fields, and set and modify field properties.

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Navigating the datasheet Navigation buttons in lower right hand

corner – one record at a time, beginning, end, new record, or type the number in.

PgUp or PgDn for page at a time CTRL + Home for beginning, CTRL + End

for end F5 moves you to record box, type record

number, enter

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Resizing rows and columns Similar to Excel Click and drag border D-click right border for autofit

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Sorting Automatically sorted by primary key

(unique identifier assigned to every table) Select sort column, hit ascending or

descending sort button Can select multiple adjacent columns –

will sort left to right Very simple – filters and queries for more

flexibility

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Selecting data in datasheet mode

Part of cell - Click and drag Entire cell – Click left edge (+ mark) Adjacent fields – Click left edge and drag Column – Click top of column (black arrow) Row – Click side of row (black arrow) Multiple columns – Click and drag black arrow Multiple rows – Click and drag black arrow All – CTRL + A or upper left box

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Rearranging, hiding, freezing To move a column, select, then drag To hide a column, select it, Format/Hide For confidential information Format/Unhide to restore To freeze a column, select it,

Format/Freeze Will go to left side To keep it in view as you scroll Format/Unfreeze to restore

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Printing datasheets Hide and/or size columns for best

view Change formats, fill colors File/Page setup for orientation and

columns Landscape is often best orientation Preview before printing

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Manipulating data

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Adding records ►* for new record Always add to bottom – Access will resort

when table is closed No need to save – when you leave record,

Access will save Records/Data entry for data entry mode Current record only – less distracting To remove – Records/Remove Filter

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Editing records Click inside field (pencil will appear

on left) Saves when you leave row or close

table Can only “Undo” last record, so BE

CAREFUL Within same record – hit escape to

Undo

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Deleting data Within a single field, select and hit

Del Select records or multiple records

from left, hit Del It will warn you once – no Undo, no

exiting without saving changes Large groups of deletes – use delete

query (Voter records purge)

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Copying, moving data Edit/Copy, Edit/Cut, Edit/Paste CTRL + C, CTRL + X, CTRL + V Use toolbar buttons You must select the same number of

fields to paste into that you copied from CTRL + ; - current date (doesn’t always

work) CTRL + ‘ - copies data immediately above

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Finding data Edit/Find Choice of column or table Choice of all or part of text Shift + F4 for future searches

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Filtering Records

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Filtering Data

By Selection Simplest; cannot sort at the same time Can also filter “excluding” selection

By Form Can use ‘and’ ‘or’ statements; cannot sort

at the same time Advanced Filter

Use a filtering grid to enter expressions and sort criteria; most like query grid; can sort simultaneously, offers most flexibility.

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Filter by selection Select data you wish to look for Hit Filter by selection button All records that match will appear Multi-filter, by adding criteria Remove filter button when finished

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Filter by form Best for simple multi-criteria Data entry form will appear Type in criteria, hit filter by form

button Remove filter button when finished

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Advanced Filter/Sort Records/Filter/Advancrd filter-Sort Most versatile of three Can sort and filter in one step Only kind that can be saved (as a

query) File/Save as Query

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Advanced Filter/Sort Operators > greater than >= greater than or equal to < less than <= less than or equal to <> not equal to * wildcard

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Advanced Filter/Sort Operators (con’t) Not - eliminates criteria from

evaluation Between – finds criteria within a

range Like – used with wildcard (*) Null – no value

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Examples of Advanced Filter/Sort Operators =CA - value is equal to “CA” >=T - value begin with letter T, through Z Is not Null - there is some value <>CA, Not CA - All values but “CA” >=1/1/91 - Date is on or after 1/1/91 Like G* - Values that start with G Not like *oak* - All words that don’t have

“oak” in them

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Advanced Filter/Sort criteria Records/Filter/Advanced Filter-Sort Drag or D-click or pulldown fields

that are involved “Specify sort (ascending,

descending, neither) Specify criteria using operators, text,

numbers Hit Apply Filter

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Multiple criteria – “and” vs. “or” If you are looking for an “and” relationship,

place both criteria on same line Vertical lines between boxes are “and”

relationships If you are looking for an “or” relationship,

place criteria on different lines Horizontal lines below “criteria” are “or”

relationships “Or” statements can be typed together in

same box (R-click for “zoom”)

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Practice session “X” to clear grid A list of orders sent to Switzerland

sorted by shipping date (18 records) A list of orders shipped outside the

USA in 1996 (123 records) A list of orders with freight $50 or

over to Germany or Brazil sorted by amount (90 records)

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Database Design

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Figuring out what you need Determine the purpose of the database.

The subjects that need to be included and the facts you need about each subject.

Determine the tables you need. Divide information into separate subjects, and have a different table for each subject.

Determine the fields you need. Decide what information will be stored in each table. Break the information down to its smallest logical parts

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Figuring out what you need (con’t) Determine which field will be the unique

identifier (key field). If there isn’t one (i.e. – SS#), Access will supply one. Names are not unique, and addresses and phone numbers can change.

Determine the relationships. Decide how the tables relate to each other. Add fields and/or tables to help clarify these relationships.

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Sample database design You have a list of workshops, people who

came, people who presented, how much they spent

You want expenses by person, by workshop, by category, various sub-totals

You want lists of attendees by workshop, by location, by interests

You want to create mailing lists for future workshops, based on interests and/or location

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4 interrelated tables Table of workshops Table of attendees Table of presenters Table of presenter expenses

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Workshop index W# - key field Name of workshop (subject/city) Facility Address 1 Address 2 City State Zip Date of workshop General Subject of workshop

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Attendee listings A# - key field W# - (pulldown menu of subject/city) Prefix FName LName Phone number Address 1 Address 2 City State Zip

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Presenter listings P# - key field Prefix FName LName Phone number Address 1 Address 2 City State Zip Yes/no field for each workshop subject

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Presenter expenses E# - key field W# (pulldown menu of subject/city) P# (pulldown menu of presenters) Date Travel expenses Food expenses Lodging expenses Materials expenses Misc. expenses

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Creating the tables Files/New/Database/Create to start

from scratch Table wizard will leads you through

decisions Design view toggles with datasheet

view

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Setting the primary key This is step 1 Default ordering by this field Access won’t allow duplicates Helps define and create relationships

between tables Usually best to have Access assign one

(SS#, pre-existing employee # are exceptions)

Hit the key icon Set data type as “Autonumber”

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Field properties – upper grid Field Name – no spaces – or other

applications can’t read it Data type – number ONLY if you perform

math functions (Zip Code, phone numbers best as text) – default is text

Lookup wizard to set up a pull down box (pre-existing or new list)

Description – will show in status bar – let others know what the field is for, how to enter data, etc.

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Field properties – lower grid F6 toggles between upper and lower Each field created in upper grid has

a set of properties defined in lower grid

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Field size Maximum number of characters an

entry could be 50 is default for text field 250 is maximum for a text field 64,000 is the maximum for memo

field

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Format Displays numbers and text in a certain

format, usually numeric – dates, currency. Different formats displayed for different

data types (text has none listed) Some text formatting: < is all lowercase,

> is all uppercase, @ will display “no data” when nothing is entered

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Input mask Inserts characters that aren’t saved

in data, but help the imputer format data – phone numbers, Social Security numbers, dates

Hit the “…“ button to see options

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Caption Specifies a label other than the field

name Spaces can be used here, as

opposed to the field name Default is field name

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Default value Automatically fills in a specific value

– current date is most common =Date() gives current date CO for home state Value can be changed after the fact

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Validation rule Limits data to certain restrictions Use Expression Builder (…) or just

type it in Use same standard operators from

advanced filters >=50 =25 or=50 or=75

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Validation text Message displayed when data

breaks violation rules “Number must be greater than or

equal to 50” “Number must be in increments of

25”

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Required, Allow Zero Length These are similar “Required” requires that data be

entered “Allow Zero Length” applies to text

and memo only, allows a blank field to be accepted

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Indexed Speeds searches on frequently

sorted or search fields Slows data entry, requires more

memory Only use when needed Key fields are always indexed

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Relationships between tables

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Types of relationships One to many – most common relationship

• Employee to Sales• Each record in Sales matches only one record in

Employee, but one employee had many sales

Many to many – strongly discouraged, unnecessary data redundancy

• Student to Classes• Each record in one database matches multiple records

in another• Solved by creating and intermediary table with one-to-

many relationships at each end • Pull the Key field from each table together in third

table is a simple way

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Types of relationships (con’t)

One to one – rare because it is two dimensional, can use Excel instead• Business information to personal

information• Allows separation of databases, store

personal information in a limited access format (password)

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Viewing relationships Tools/Relationships Drag around boxes, size boxes, lines will

move Common fields are linked by lines Key fields are in bold Key fields are often, not always, the

linking field Infinity symbol means many, 1 means 1

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Forming and editing relationships R-click on line to edit or delete

relationship Click and drag one field to same

field in different table to form relationship

One and many icons don’t show

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Forming and editing relationships (con’t) Click on line to edit properties “Enforce referential integrity” will turn

them on “Cascade delete” will delete all records

with references to that record – BE CAREFUL

“Cascade update” is not as dangerous – will update all affected fields

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Extra credit! Can you find the table created to

link two many-to-many relationship tables together?

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Queries

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Two kinds of queries Select queries

Allow you to select, view, and analyze data

Action queries Allow you to modify data 4 kinds: Update, Delete, Append, Make

table

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Creating a query Select the database Queries/New Design view Select needed tables from the “show

tables” box Close the box Tables must be connected, or all

permutations will show, and your PC will crash

Intermediary table can be used

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Select the fields Drag or D-click or pull down needed

fields to the field boxes To add all fields, click asterisk or D-

click the Table header

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Specify sort order Not required, but good to find an

easy way to look through the data Ascending or descending in selected

field More than one field selected, will

sort left to right You can sort with a hidden column

to circumvent this

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Specify criteria Limits results of the query Use same expressions as advanced

filter Multiple criteria use “and,” “or” Horizontal lines are “and” Vertical lines are “or”

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Expressions and calculated fields Bring up the tables you are working

from (Queries/New/Design view) In Field grid, put field names in

brackets Join or calculate fields with

expressions R-click, choose build to build with

buttons

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Expression and calculation examples [FirstName]+” “+[Last name] [City]+”, “+[State]+” “+[Zipcode] [UnitPrice]*[Quantity] [UnitPrice]*.25 Expr1 is default column name, type

in your own to left of colon

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Parameter Queries For queries you run frequently, with

different values Design query normally, type prompt

text between brackets [Enter the last name], or [Enter the

date] When someone brings up the query,

it will prompt them for the variable

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Save your query Use save button, or File/Save Use default name or name it

yourself After save, it becomes part of the

database, and will show when you hit the queries button in the database window