1. Navya Thum navya.thum@mail.wvu.edu March 04, 2013
Microsoft ACCESS
Navya Thum
March 04, 2013

2. Attendance
Go to to record attendance.
Enter your MyID username and password.
11/18/2018

3. Databases & Relationships
Now that we know what a table is, let’s talk again about databases …
A Database is a collection of tables
If Tables are related, it is called a “Relational Database”
A Common Field between tables is what allows a relationship to exist. This works by way of “Primary” and “Foreign” keys…
11/18/2018

4. Primary Keys - revisited
Primary Key – Field in every table whose field values are unique for every record
Examples might be things like:
Student ID numbers
Cell Phone numbers
Anything that will not have duplicates as additional records are entered
11/18/2018

5. Relationships Foreign Key – Similar field in a related table
Primary key field in relationship will have similar data type and content to foreign key field
The two tables are joined together on the primary and foreign keys and form a Common Field.
11/18/2018

6. Relationships
The link formed through this Common Field which is dubbed in one case as a “primary key”, and in another as a “foreign key”, allows tables to share data
Note that the “Look Ahead” database has 3 tables, but we will only look at 2 today…
11/18/2018

7. 1: Employees Table…
EmployeeID is the Primary Key as all numbers are unique for employee records
11/18/2018

8. This will tie back to the Employees table.
2: Locations Table…
LocationID is the primary key and each record has a unique LocationID designator.
This will tie back to the Employees table.
11/18/2018

9. Relationships
Databases are all about efficiency and not having to store the same information more than once if multiple records can use it
In this example, we know that multiple people work at the same office address. One address can have many related Employees (One to Many)…
11/18/2018

10. Relationships
Instead of typing the same address in each record for every Atlanta office employee: “450 Peachtree Road…”
We can assign a simple relationship to a “Locations” table and reference this information to a given location with a short common code of “L01” between the tables…
11/18/2018

11. One to Many Relationship
(One instance here)
(Many here)
Typing “L01” when entering an employee and having it equate to the entire address saves MANY characters in databases as it is reused over and over.
“L01” is 3 characters and the entire address is over 30 !
11/18/2018

12. Summing up what was just mentioned
Each table has a primary key that has a unique field value
In one of the tables, there is a foreign key
In Employees table
Has the “Employee ID” as the primary key
Locations table
Has the “Location ID” as the primary key
That “Location ID” ties back to a “Location ID” field in the Employees table (where it is considered the Foreign key)
What we need to do now is to join them 
11/18/2018

13. Making the Relationship
These tables need to be tied together (related)
to work this way…
Open the Relationships Window through:
Database Tools ribbon > Relationships
Right click blank space and select “Show Table”
Double click “Employees” & “Locations” tables to be able to establish the relationship between them.
11/18/2018

14. The Relationships Window
Click the “Close” button
The Relationship window allows us to see structures representing each added table
Within the structures, we see the fields that each table has
Primary keys are shown with a key icon …
11/18/2018

15. Making the Relationships
Drag “LocationID” from the “Locations” table to “LocationID” in the “Employees” table.
Notice the “One-To-Many” reference
Click to Enforce Referential Integrity
Click “Create”…
11/18/2018

16. Relationship Formed (Relationship Primary Key)
Note the One to Many
(1 to infinity symbol) that formed on the join line…
Close and save the relationship
Run the “Employee Information” query to see data pulled together from both tables…
(Relationship Foreign Key)
Note, the relationship we made was already created in the query we ran and we did this only for increased understanding of how to create relationships.
11/18/2018

17. Query Results
Information is pulled from the “Employee” and “Locations” tables through their relationship and shown united within the query results to give us a complete picture of the information !
The LocationID field was used behind the scenes to pull it all together.
Everything is stored efficiently and we are able to see everything we need together all at once.
11/18/2018

18. Access Chapter 2 Doing it from Scratch
Creating a Database
Creating Tables
Creating Fields
Field Properties
11/18/2018

19. Premise
We are going to create a school database to keep information on students and programs at WVU
Table Creation
Fields, Data types, other attributes
Establishing Relationships
Entering Records
11/18/2018

20. Building the Framework
Open Access
Select “Blank Database”
For “File Name”, Call it lastname_firstname_accessexample4.accdb
Save to Desktop (This is important)
Click “Create”
Set the Objects bar to “Object Type” to see “All Access Objects”
* Note that nothing exists in the objects area yet
11/18/2018

21. Designing Databases
When designing a database, try to think of all the fields of data that need to be stored
Group the fields into tables
Each table will contain a group of fields
Select a field in each table as a primary key where each field value will be unique …
11/18/2018

22. Designing Databases
We want to break out information that may be redundant and include it in separate tables…
When tables will be related to one another, you need to include a common field in each of the tables that will be used to form the relationship
Primary key in one table
Foreign key in the other table
11/18/2018

23. Planning
We need to consider what types of information our database will hold
Assuming that we wish to keep records on students, we will want to have the following information: First and Last names, address, phone, major, and student number…
11/18/2018

24. Drawing it all out
To be versatile, we will want to make multiple fields for name and address elements to split the information up:
FirstName
LastName
StAddress
City
State
Zip
… breaking things up helps us in searching later on
11/18/2018

25. Drawing it all out We will also have fields for these items:
StudentNum, PhoneNum
Major, will be used over and over
One major to Many people
This screams “One to Many relationship” and we can make a separate table for the majors with a common field of “MajorID”
Second table fields: MajorID and MajorName
11/18/2018

26. Assigning Field “Data Types”
Data Types specify types of field values you can enter for the field, how they can be used, and what other properties the field will have
They essentially control what kind of information may be entered as field values for a given field
Let’s look at what kinds are available…
11/18/2018

27. Access Field Types …
11/18/2018

28. Access Field Types
11/18/2018

29. Naming Fields Fields and Tables need to be named
It is good to pick meaningful names
Names can be up to 64 characters
Names need to be unique
Can contain letters, numbers, and some special characters
Spaces generally not used
Can put capitol letters at the start of words to show separation. ex: TwoWords
11/18/2018

30. Field Sizes Access has default field sizes that can be overwritten
Setting a Field Size tells Access how much space to allocate for fields
It should be only as large as the maximum-size piece of data needing to be held
Making it too large will waste disk space as it is consumed whether filled or not.
11/18/2018

31. Field Captions
The Caption Property allows us to customize the way a field name will show up in a report or form.
If we do not specify one, the regular field name will be used
Because we do not use spaces in actual field names, they may not be easy to understand in reports. The caption lets us make names appear more like regular English words if we choose
11/18/2018

32. Creating the First Table
With “Table1” selected in the Objects bar, Click the ruler to enter “Design View”
Name the table StudentInfo and click OK
We now see the following…
11/18/2018

33. New Table in Design View
Note that a primary key field is already created
We can change the name of this field and add others…
11/18/2018

34. Making the Fields Create the following Fields:
Replace “ID” with StudentNum of Data Type Number
FirstName of type Text
LastName of type Text
PhoneNum of type Text …
11/18/2018

35. Making the Fields MajorID of type Number StAddress of type Text
City of type Text
State of type Text
Zip of type Text …
11/18/2018

36. Making the Fields Change Text Field Sizes to be “20”
Put descriptions on StudentNum & MajorID
Students ID Number
Foreign Key to related table
Put captions in fields that have abbreviated names
11/18/2018

37. Making the Majors Table
We said that we would like to create a separate table to have the majors listed as many students will have the same major and this will save a lot of space
Close the StudentInfo table & Save the changes
Select the Create Ribbon
Choose Table
11/18/2018

38. Majors Table
* The first field will be MajorID and the data type needs to be Number to match the MajorID field in the first table that we will relate it to
Go to Design View and name it Majors
Create the MajorID field of type Number
Description: Primary Key related to StudentInfo table
Create the MajorName field of type Text …
11/18/2018

39. Majors Table Completed
Verify MajorID is the Primary Key
Flip to Datasheet view, saving changes, and enter the following records in this table…
11/18/2018

40. Entering Data in Majors Table
Close the table
11/18/2018

41. Enter Records in StudentInfo Table
Open the StudentInfo table in datasheet view
Create 4 student records and enter all data for them (make up names and such)
Make 2 of them MajorID 2
Make 1 of them MajorID 1
Make 1 of them Major ID 3…
Close The Table!
11/18/2018

42. Reasons to Relate Establishing relationships between tables can:
Eliminate redundancy
Waste Less Space
Reduce data errors / Inconsistencies in duplication…
11/18/2018

43. Including a Common Field
When one table needs to be related to another table, we include a common field
The common field will be the primary key in one table and foreign key in the related table
In our example the MajorID fields are common
Primary in Majors table and Foreign in StudentInfo …
11/18/2018

44. Let’s Relate Our Tables!
Make sure both tables are closed
Always close tables when working on them directly, otherwise you may get errors when things are in use
Database Tools ribbon
Select Relationships
Double-click each table name to add them …
11/18/2018

45. Creating the Relationship
Drag MajorID from Majors table to MajorID in the StudentInfo Table
Enforce Referential Integrity
Click Create
Close the Relationships window & save
Close Access
11/18/2018

46. Making a Multi-table Query
Create ribbon > Other group Query Design
Add both tables and close “Show Table”
Expand the StudentInfo table to see all fields
* Notice the relationship showing
11/18/2018

47. What will happen?!
We want the query to show the student number, first and last names, phone number, full address and name of their major (not number)
We will not use the MajorID field because remember that we don’t want to see the number
The relationship that we established already will use the common field to get the MajorName for us by it using the MajorID number!
11/18/2018

48. Add Fields to the Query
Double click to add the fields in the order we want them to be displayed
StudentInfo Table
StudentNum, FirstName, LastName, PhoneNum, StAddress, City, State, Zip
Majors Table
MajorName
11/18/2018

49. Run the Query! Click the ! Up top to run the query
Notice that the information was pulled together out of both tables to be able to get you the words for the MajorName and all the other data together
11/18/2018

50. Keep the query to use again
Close the Query
Save the query as StudentQuery OK
 “Queries” is added to the Objects Bar
In StudentInfo add a 5th student
Close the StudentInfo table
Rerun the Query
11/18/2018

51. In-Class EXTRA CREDIT ! ! ! Close Access & Go to the CS101 Web site
Use Homework Submission Tool
Browse and upload for 2 points of credit.
Submissions NOT ACCEPTED outside of class!
>> Extra credit exercises are to be done in class. Those submitted out of class will be considered violating the academic dishonesty agreement.
11/18/2018

52. For next class, 03.18.2013 – MyITLab Lesson C due
Walk through today’s slides to better understand the “Relationships” concept.
– MyITLab Lesson C due
– Homework 4 is due
HW4 is posted now on the assignments page.
11/18/2018

53. Questions?
11/18/2018