Ms Access Ism

7/27/2019 Ms Access Ism

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Basics DBMS : Data Base Management Systems.

DBMS: An abstraction of an enterprise related to anenterprise

It is used to store data of the enterprise

Data: Transactional Data and other type of data

DBMS: Allows enterprise to store, retrieve, update, delete and backup the data.

Life Cycle of Data: C Store, Retrieve, Update, Backup and

Delete

The alternative to DBMS was File System

In File System, data are stored in one or more data files.

Data Files can be of different types.


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Basics Problem with File System

Redundancy of Data Same data in different files Access through Programmers (no SQL like access)

Sharing data among different users is difficult Explicit lockingby programmers

Difficult to answer adhoc queries

Many data files are created. Explosion of files

Update problems

No centralized control

Access controls has to be implemented by programmers

Files are created for specific purposes in most cases as suchare specific for the purpose for they are created

Time to develop applications


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Basics DBMS

Designed taking into account enterprise view Centralized Control

Access Controls enforced by DBMS

Reduce Data Redundancy

Developed for Data Sharing

SQL can be used to store data, retrieve data and update data

Automatic backup and recovery features

Programming Languages access through standardized DBMS

interface

Easy to applications. Many tools are available

Manage large volume of data


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RDBMS Relational Data Base Management System (RDBMS)

RDBMS: It views data as collection of tables. A Table has row and columns (two dimensional structure)

Entity Relationship Diagrams are used to model tables

A row represents record

A column represent an attribute

Primary Key

Different tables can be related by table values Primary Keys,

Foreign Keys

RDMS Design: Reduce data redundancy and update anomalies

Data Normalization

Referential Integrity


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MS Access MS Access is part of MS Office

It can be used to store data As such there is overlap with some other products available in

MS Office and from other vendors

Although there is always overlap, the following rules mighthelp when deciding when / when not to use MS Access:

MS Access is best used for long-term data storage and/or datasharing.

MS Excel is best used for minor data collection, manipulation,and especially visualization.

SPSS is best used for minor data collection and especially dataanalysis.

It is easy to export data from MS Access to Excel SPSS


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MS Access Cheap, readily available (packaged with MS-Office Premium).

Easy to use (relative to other systems )

Easy to use Interface

Wizards

Oracle may require one Engineer to maintain the server as a

database administrator

It also requires another engineer to serve as an application

developer

MS Access Includes front-end tools for rapid application

development (RAD). This also makes MS-Access a good

prototype environment.

All programming languages can use it.


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MS Access Although the term database typically refers to a collection

of related data tables, an Access database includes more thanjust data.

In addition to tables, you can add:

Saved queries (stored procedures) - organizing and/or

manipulating data Forms gui interaction with data, event programming

Reports customized results for printing (~ static forms)

Macros and VB programs for extending functionality

Microsoft provides some logical integration of these toolsthrough wizards. However, these are pretty basic - mostdevelopers must pick and choose the best approach whenimplementing applications.


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MS- Access File

Unless advanced techniques are

employed, all entities are stored

in one *.mdb file. When

running, a locking file (*.ldb) is

also visible. Only the mdb file

needs to be copied to transferthe database to another

computer or location.

Ex.MSCI_ByrneGuestLecture.mdb


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MS Access File

Demographics Ethnicity Labs H & P

Tables

Queries

Forms (Active)Reports (Static)

VB + Macros Event Driven Automation, etc.


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Applications

Back-End File - Contains all Data Tables

VB + Macros Event Driven Automation, etc.

Demographics Ethnicity Labs H & P

Tables

Queries

Forms (Active) Reports (Static)

Front-End File - Contains all Application Entities (Forms, Queries, etc.) and links to

data tables in back-end file. Note you may have more than one FE to

accommodate different user types.


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MS Access and Objects

Relational data model

Data is stored in tables incorporated into databasefiles with extension mdb or accdb

Standard Windows interface

Standard Help system

Part of MS Office suite

Tables contain rows called records and columns calledfields.

Queries are requests for specific information from adatabase.

Queries are virtual tables built on a given SQL statement


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MS- Access Objects Forms are parts of user interface. Forms are used to enter, edit or

browse data from a database Reports present requested information and allow to create hard

copies.

Microsoft Access is a relational database management system(DBMS or RDBMS). At the very core, it is a software engine that

provides an interface between physical data and user applicationqueries.

Other examples of DBMS applications include:

Oracle

mySQL

SQL Server (Microsoft)

DB2 (IBM)

Informix


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Tables Overview

Think of Access as a collection of

spreadsheets that are relationally linked.

STOREDATAON

ETIME/ONEPLA

CE

DONOTSTORECALCULATEDDATA

Demographics

Patient_IDFname

Lname

Address

Phone

Gender

RaceDOB

Height

Glucose

Glucose_IDPatient_ID

Date

Weight

Med_ID

Glucose

Meds

Med_IDDrugCombonation


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Data Types

Text

Memo

Numbers

Byte

Integer

Long integer

Single

Double

Date/time

Currency

AutoNumber

Yes/No

Yes/no

True/False

1/0

OLE Objects

Hyperlink Lookup Wizard


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Create Table Click on the round Office button

Choose Newfrom the drop-down menu

In Create Blank Database window specify the database name

Click Create

Using Wizard

Design View

Specify field names

Data types

Properties Determine a primary key

Save the table


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Access Tables and Constraints Design view

Table structure is created and may be edited Datasheet view

Display table content in spreadsheet-like grid,

Used for entering, editing or deleting data from tables

Referential Integrity

Can be established or removed in Relationship window In MS Access 1995-2003 open menu Tools and choose

Relationships from the drop-down menu

In MS Access 2007 and up choose Database Tools tab and thenRelationships

Use drag-and-drop features and select Enforce Referential Integrityoption

Tip specify referential integrity constraints before data is entered


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Tables

General Setup for Tables

Describe General Options

Show Validation Rule

Relationships

Lookup Option


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Tables

Table Relationships

Describe Cascade Features


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Table Import

Importing a Table makes a copyof existing data

Linking a Table lets you control

existing data through Access

(Exercise Caution !)

Note that you may

import non-Access

files.


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Tables Data storage principles

Attempt to store data 1 time / 1 place; Do not store data that may be calculated from other fields

(utilize queries); and

Strive for very discrete data storage (no ambiguity garbage

in / garbage out). Choose real or arbitrary (autonumber) unique identifier for

each record.

Relationships

Use table relationships to automatically cascade delete andupdate records.

Other Data Sources

Import = Copy; Link


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Query

Specify the source of data

If multiple tables are used, specify relationships between tables

Select desirable fields from the table(s) and options related to the

fields

Specify a criterion

To be selected a record must satisfy a criterion

Expressions may contain the following operators:

Math Operators

Relational operators

Boolean Operators

String Operators

Miscellaneous Operators


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Math Operators

+ Addition

- Subtraction

* Multiplication/ Division

\ Integer Division

^ ExponentiationMod Modulo (remainder) division


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Relational Operators

= Equal

Not equal< Less than

> Greater than

= Greater than or equal to


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Boolean Operator

And Logical And Both operands are true

Or Logical Or Either one of the

operands or both ofthem are true

Xor Excusive Or Only one of the

operands (not both ofthem) are true

Not Negation Operand is not true


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String and Miscellaneous Operators

& Concatenation

Like Similar to

Betweenand

Between 2 values inclusive

In (list) One from the listIs Null True if the field is empty


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Query Queries Retrieve Data

SQL (Structured Query Language) is a very widely useddatabase language designed specifically for communicatingwith databases

SQL is not proprietary almost every DBMS supports SQL(including MS-Access).

An MS-Access query is a set of stored SQL instructions thatmanipulate and/or select data from one or more tables.

Select Query Data grouping and/or filtering

Make-Table Query Select + creates/populates new table.

Update Query Updates fields from specified table data

Append Query Runs query on one table, appends results toa table

Delete Query Delete selected records from table


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Query SQL is relatively easy to learn, but extremely powerful

One of the easiest ways to learn is to use MS-Access Query by

Example methods (QBE), It also generates corresponding SQL Statement .

After QBE one can look at the generated SQL command

Remember that a query is nothing more than the database enginerunning the stored SQL command

It looks and sometimes acts like a table, but really adds little massto the database file.

In Query, Name the calculated field, then type a colon, then typethe equation using brackets ( [ ] ) around table fields.

If there is ambiguity in the field names between tables, you may

need to type table.[field] format. Ex: BMI: [Weight]/([Height]/100)^2

Select , Insert , Delete, Update with where


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Query Sorting Data

Choose Ascending or Descending in the Sort Row

This query would sort by Gender THEN by Race.


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Query Filtering Data

This query will return all records in the database for:Females

who are not white

whose height are greater than 150 cm

and who weigh between 60 and 70 kg

Youneednotshow

thedatafieldto

useasafilter.


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Query Grouping Data

Clicking the Totals Button EnablesGrouping, Counting and Statistical Options

Notice new Total row.

Each field (column) can be set.

Running this Query

indicates there are

203 Females and

261 Males in thedatabase.


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Query Grouping Data

Totals Options Include:

Group By

Sum

Avg

Min

Max

Count

StDev

Var


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Query Export Data

Create and Save Query1)

Use OfficeLinks (Excel Toggle Option) to

Analyze it with Excel2)

Data Automatically Exported to

Excel3)


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Query

Queries are extremely easy to set up/use

They provide an up-to-date snapshot of your data at any time.

Queries may be used to calculate values based upon existing

fields, join fields from separate tables, globally update or

delete data, and export linked/calculated data to external

programs. Different types of joints

The queries are really nothing more than stored SQL

statements that are run upon command. They add little mass

to the file application. If you use MS-Access its important should feature is to import

data and export it.


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FormsAlthough it is possible to enter data directly into a table, onecan enhance data quality by forcing data entry through forms.

Depending upon the type of users, one may wish to set thingsup so they never even see the database window.

In other words, one can design your application so they onlytouch the data through programmed forms.

As an example one see that in case of the glucose databaseearlier slides one can attempt to build a graphical user interfaceto:

Collect Data

Periodically report data through pre-formatted reports

Quit the program

So the user will be unaware of the existence of table


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GUI Forms

Out of Program


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MS Access Forms Create using Form Wizard

Create using Form Design view Specify source of data will be presented by the form

Table

Query

Specify fields related to the form Add labels, titles, graphics and so on

Form Design View : Form Headera place for titles, graphics,additional information

Form Details section the fields used to create a form andcontrol elements related to the fields

Form footera place for any items which will appear at thebottom of the form


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MS Access Forms A Form can be associated with a Table

Must be bound with fields from the source table or query Contain data from correspondent fields, labels or other

controls (like command button) or another form calledsubform

Viewing Forms: Open database

Click Forms tab to display all available forms in the database

Select the form

Select Open

To view data use Form Navigation Tools. To prevent data

Editing, use Locked Property for the Text Boxes

Forms can be used for editing data

The results of query can also be displayed in form


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MS Access Forms and Reports Sub Forms

A Form can have many sub forms

Represent 1:N relationships

To add a subform to a form

Create a form that will be a subform

Click on Subform/Subreport button and then click on a

form where the subform should appear

Specify the source for the subform

Specify the fields to link the form and subform

Reports present table contents or query results in an easily

assimilated format

Reports have Design view and Print Preview

Report Design View is similar to the Form Design view


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Reports Page Header contains data and graphics appearing at the top

of each page

Report Header contains the data and graphics appearing atthe top of the first report page

Detailed section contains data from tables or queries

Page Footer contains the data and graphics appearing at thebottom of every page

Report Footer contains the data and graphics appearing atthe bottom of the last report page

Reports can be of following types

Columnar reports a single record on a page

Tabular reports datasheets: fields from the tables arepresented as columns

Justified reports combine two previous types of the reports


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Creating Reports With a Wizard

Design view:

Specify source for the report . The source is one or more

tables.

A Query can also be specified Select Fields from the Fields List

Add labels Used for titles and captions

The headers can also be described here

The data formatting can also be done

Switch the view to see the result.

Documents

Ms Access Ism