Intro to Access & Macros

CSCI130-03AInstructor: Dr. Imad Rahal

LAYER Order

Application SW: Excel & Access

2

High-order P.L.: Visual Basic

1

Low-order P.L.: Assembly 3

System Software: O.S. 3

Machine Language 4

Data Representation 5

HW: Circuit Design 6

Introduction What is a database?

Collection of related data arranged into related tables of rows & columns

Different from Excel? Suitable for large data sizes Models a complete business Provides stronger built-in data access functionalities

Rather than building them from scratch as in Excel Provided thru a DBMS

Works with data of interest only

What is a database management system (DBMS)? A collection of complicated software programs that organizes the data in a

database and allows users to insert, update, delete or retrieve subsets of the data

Other provided features include: Access Control, Recovery, Concurrency etc …

Introduction A Table holds data for one entity of the business

University example

Table is divided into rows called records (or rows) One row describes one unit in our table E.g. one employee, product, customer, etc …

Row is divided into fields (or columns) Properties of the entity E.g. properties of an employee: Name, address, salary, position, etc …

Student table in a university database? Fields? Records?

Every table must have a unique key Unique value for every record in the table to assist in maintaining data integrity (Key field) If more than 1 key exist, one is designated as primary key Student table in university database

Unique attributes (key fields?) Primary key?

Designing a Table in Access

Office ButtonNew under “Blank Database” on the right

Name your database file Choose its storage location Click on Create button

A window appears: under the “AllTables” section on the left

Click on the down arrow Select “Object Type” Click on the down arrow again and observe that now you can

see all objects that can be created in Access: Forms, Tables, Queries, Reports, Macros, etc …

Select “Tables” and double click on the only table in the menu (usually called Table1)

In the upper menu (right above “Table1”): Click on View and select “Design View”…save table if prompted

Field part: Name and description of every field Properties part: specific properties for each field

Designing a Table in Access

In addition to the type (Field Part), we need to set the following properties (Properties Part) Required: Determines if the user is required to enter

a value for this field for every record Default Value Input Mask: (for Text and Date fields only)

Sets a suitable pattern mask for data to be entered like ###-###-#### for SSN We can choose from common masks

# number, space, or plus or minus L A letters A a letter or number

Designing a Table in Access

Validation Rule: Determines what is a valid for this field Department in EMPLOYEE table must be limited to certain names

In (“Sales”, “Production”, “Management”, “Design”) < #1/1/1995# LIKE "#####-####“ LIKE "*smith##*" LIKE "??00####"

Validation Text: specifies the message output to the user in case in valid input is provided (e.g. ‘Not a Valid Department’)

Set one field as the primary key Select the field Click on the key icon on the toolbar (notice the key appears

next to the field)

Queries A selection function

selects certain fields and records from a table according to certain criteria & displays results in a new table for a report

Record filter Update, delete, & insert data into a table

Select Queries are very common The produced table is a subset of the database

Limited by selected fields and matching records Used to summarize or do simple calculations on the

data in the database

Queries Click on the down arrow

on the left next to where it says “Tables”

Select “Queries” and double click on the only table in the menu (usually called Table1)

On the top menu, click on the “Create Ribbon” and then click on the “Query Design” button in the “Other” group

to be displayed in the query or that participate in the selection

criteria (Not limited to the given fields)

Derive others

Queries For each field we can

decide to Show it Specify criteria to be

met (Numbers)

= 25 <= 10 Between 5 and 10

(Strings) “Management” “Sales” or

“Design” Not “Sales” In (“Sales”, “

Design”, “Production”)

Like “S*”

(Dates) < #1-May-99#

Sample Queries on Gargoyle DB

01 Accounting Employees (simple selection query) Select first name, last name & Dept “Accounting” Dept

02a Management Fulltime Employees (uses AND) First Name, Last name and Salary “Management” and “Fulltime”

Same “Criteria” Row

03 Sales or Management Employees (uses OR) First Name, Last name, and Department “Management” OR “Sales”

Sample Queries on Gargoyle DB

02b Management or Fulltime Employees (uses OR for different fields)

First Name, Last name and Salary “Management” OR “Fulltime” Different “Criteria” rows

04 Employees by Department (parameter query) First name, last name User inputs department Parameter Queries

Substitute an input box for a criterion specified by the user each time the query is run

Good when criterion may vary but with the same selected fields

05 First Names beginning with m First names Like “M*”

Sample Queries on Gargoyle DB

06 First Names with 'a' as the second letter (wildcard char) First names Like “?a*”

? Any character * Any set of characters

07 Names (Derived fields: uses Concatenation) First name & “ ” & last name, Department, Salary Reference fields in expressions between square brackets []

Expressions have names that appear in table Not limited to table fields Sorting on one attribute (department)

09 Salary with Bonus (Derived Fields) “Lastname, Firstname” , salary + bonus Sorting on one attribute (Full name)

Sample Queries on Gargoyle DB

**08 Salaries of employees hired in 1999 (uses a date function) Lastname, firstname, & salary Year, Month, Day Hired in November of 2000? Sort on LastName

18 Orders within the last 5 years year (use of Now()) OrderDate > Now()-5*365

10 Salary Data (uses several aggregate functions) Sum, Avg, max, Min salary Notice the new Total row (3rd)

Can be added by clicking on the Totals icon in toolbar (SIGMA)

11 Salary Averages (uses grouping and a aggregate functions) Average salary by department Format currency

Sorting Displayed Data

On a single field Click anywhere in the corresponding column Click appropriate sort icon in toolbar

More than one field Order fields by sorting preference Sales or Management Employees

Action Queries Don’t create tables meeting search criteria

Unlike select queries

Change the data in tables in all records based on some criteria Their actions can’t be undone (once saved)

Why do we need them…why not just do it in datasheet view?

Four types Update queries

Edit data in an existing table Delete queries

Remove records that match some criteria from a table Append queries

Add new records from table to the end of another Make-table queries

Create a new table consisting of the records that match a given criteria

Action Queries To create a new action (update) query

Create a Select Query and make sure it selects the desired data (Add appropriate criteria)

Choose type from Query Type group

Query 14: Rename “Sales” to “Profit” (update query) On table Employee Update “Sales” dept. to " Profit”

Query 15: 5% raise for full-time employees (Update Query) On table employee %5 raise for full time employees

Query 19: Delete employees with first names starting with “Ma” (Delete query)

Reports Display data in an attractive form usually for printing

Reports are usually based on queries (MUST CREATE QUERY FIRST)

Start at the Database window Click on “Create” ribbon On the report group, click on “Report Wizard” Select which query to base your report on Select the required fields Choose fields for grouping levels

Has its entries as the headings on the report Employees by department

Can group on more than one level Choose layout and print style and then name it

Reports Build a report based on the demo query

Show single grouping level More than 1 grouping level

Click on grouping field then on > sign Show design view

(query 12) Employee And Manager List (relationship query) Department, Manager and Employee Full name Build sample report on

Relational Queries (query 12) Display vendor contact info (contact

person and phone number) for inventory products (relationship query)

Query: Inventory Product Info

Relational Concepts Employees of a department make

orders for requested products

Not all tables are linked Only related ones Two tables can have multiple

relationships

Table relationships/links can be One-to-many

One department can have many employees One-to-one

Limit every department to one employee In Access, can’t be many-to-many

EMPLOYEESEmployee#*Department

DEPARTMENTS

Department name*

Inventory

Product number*

PURCHASE ORDERSProduct number

Emp Number

1 M

1

M

M

1

Linked fields don’t need to have the same nameE.g. Department & Department name But must contain data of same data type Field must be key in at least one table

primary table vs. related table Referential Integrity:

Every department in EMPLOYEES (related table) must exist in DEPARTMENTS (primary table)

The link is activated by a Join operation Inner Join Left Outer Join Right Outer Join Try Vendors and Inventory

Using Multiple Tables

Using Multiple Tables How to create relationships between tables?

Click on the “Database Tools” tab On the Show/Hide group, click on the “Relationships”

button Right click on pane and select “show table” To remove tables from window

Select Table Right Click Hide Table

Join tables Click on the field of one table and drag it over to the

corresponding field in the other table A window appears that describes the relationship

Key Field 3 Types of

Joins

1 to many

Used when a record of Departments (primary (1st) table) has its Join field changed what would happen to corresponding fields in Employees (related (2nd) table) records?

If not clicked no ref. integrityIf clicked Every record in related Table must have a matching record in primary table; two other boxes

Cascade Update Cascade Delete

The 1 is for the primary tableReferential Integrity: We can’t have a record in the related table that has no matching record in the primary table

Cascade Update If join field of some record in primary table is updated then update corresponding field in related table recordsE.g., “Design” “Development” in Departments, then automatically all “Design” in Employees become “Development”

Cascade Delete If record of some join field in primary table is deleted then delete corresponding records related tableE.g. if we delete the “Design” department from Departments, then automatically delete all Employees record in the “Design” Department

Types of Joins Decide how we go about concatenating records from

related tables into 1 table 3 options are given : Reason: not all records in primary

table have matching records in related table E.g. Department = { (‘CSCI’, SJU), (‘MGMT’, SJU) , (‘ACCT’,

CSB)} Student (name, Department) … 2 CSCI, 1 MGMT and 2 HIST

Inner Join (1): includes data only from records have matches records in both tables

Left Outer Join (2): includes all records from primary even those that have no matches in related

Right Outer Join (3): includes all records from related even those that have no matches in primary

in case referential integrity is not specified NO JOIN!

Types of Joins (Query that JOINS Vendors &

Inventory) Drop Join and show result

Inner Join: Inventory items with vendor information

Left Outer Join: All vendors will be shown even those not providing inventory items

Right Outer Join: All inventory items will be included even those with no vendor info

NO JOIN!

Forms To view, input and update data in a database one

record at a time What about reports? Allows for easier input and edit operations Based on a table

unlike reports which are based on queries

To create a form Click on Create tab On the Forms group, click More Forms >> Form Wizard Select the table used as a basis for the form in addition to all

fields to be included Forms for input should include all fields Forms for editing need only to include the edited fields

Forms Select one of the built-in layouts

Can be edited or changed later on Choose the background pattern Type in a name for the form Change the form to look as you’d like

Add pictures, move elements, add common elements like menus, list boxes, or buttons

To modify, the form’s design either Select Modify on final window of Form Wizard Open form in Design mode

Form window is split into 3 regions (header, detail and footer)

Build Employee form Add & Update records

Forms To add a header

Place cursor on the boundary between header and detail

Drag till you get proper space Add text to you header by

Clicking on Label icon in the VBA toolbox Moving to the header Entering text

At the bottom of the form, notice the number of the records we are viewing Use arrows to move from record to record for editing Click on the arrow followed by a * to get a blank form

to fill a new record

Macros in Access Macros are usually assigned a command button so they can be

executed with a single mouse-click

Two ways: Using built-in actions (from a drop down menu)

Create macro and then hook a button to it Using VBA macros

Create button along with macro

Access has built-in subroutines called actions segments of VB code written to perform common tasks

A macro consists of one or more actions put together to accomplish a task for the user

In general, Access macros are created using a menu system to choose the desired actions to be performed

A simple macro: - “Move to next record” button- GoToRecord action- If you go beyond the available records you’ll get an error message

Creating Macros Using built-in actions

Select Macros from list of objects on the database window Choose Create >> Macro >> Macro

Add desired actions along with their descriptions E.g. GotoRecord, Msgbox, OpenForm, OpenQuery, OpenReport,

OpenForm, Quit, RunMacro, Save, Maximize, Close, etc … OutputTo Save macro with an appropriate name

Insert button (Cancel button wizard if it starts) Right Click Properties ALL Tab

Change Name & Caption (Use name conventions) (Scroll down to) On Click

Click inside entry and then on down arrow (DO NOT CLICK on the three dots button)

Select from list of available macros

Accessing Access from VB Concept of a RecordSet (cursor)

Form is linked to a table through a recordset An exact copy of the table that we can manipulated in the form

Important code comments (1) Dim myDB As Database (2) Dim myRecords As Recordset2 (3) Set myDb = OpenDatabase(App.Path & "\Gargoyles.accdb") (4) Set myRecordSet = myDb.OpenRecordset("Employees")

Any table name or could set it to a query (5) myRecordSet.Index = "PrimaryKey“

Relative movements are defined in PrimaryKey Order

Accessing Access from VB Operate on a record set

myRecordSet![FieldName] to access value of field for current record in recordset

myRecordSet.EOF to check if we are at the end of the recordset

myRecordSet.MoveNext Does not change the record currently displayed in

form Same applies to the following commands

myRecordSet.MoveFirst myRecordSet.MovePrevious myRecordSet.Move 10

Moves 10 locations from current record Relative Movement

Accessing Access from VB Get the info from the current record in

the recordset MyRecordSet![FieldName] MsgBox myRecordSet![FirstName] & " " & myRecordSet!

[LastName]