Download databases

CHƯƠNG 2
Creating and Working with
a Database
1. Planning a Database
• Example:The same information stored in a
poorly designed table and in a well-designed
table.
1. Planning a Database
• Use multiple tables so that you don't duplicate
information: The same information stored in a
badly designed table and in a well-designed
table
1. Planning a Database
Here are some guidelines for creating a welldesigned database:
• Determine the Purpose of the Database: This
will help determine the tables and fields to
include in your database.
• Determine the Fields You Need: This should be
an easy step once you have determined the
purpose of your database and have sketched
some sample reports and lists.
1. Planning a Database
• Determine the Tables You Need: Each
table in the Database should be based on
only one subject
• Determine the Primary Key: Each record
in a table should have a primary key that
uniquely identifies it
• Determine the Relationship between
Tables
• Sketch a Diagram of Your Database
1. Planning a Database
• Each field or column should contain the same
type of information
• Try to break up information as much as possible
• Use multiple tables so that you don't duplicate
information in the same table
• Don't use duplicate field names
2.Creating a Database Using the Database Wizard
• To create a database using the database wizard:
– Click the new button on the toolbar or select
file new from the menu.
– Click the on my computer link in the task pane.
2.Creating a Database Using the Database Wizard
– Click the databases tab in the templates dialog
box.
– Double-click the type of database you want to
create.
– Follow the onscreen instructions and specify
what you what to appear in your database
3. Creating a Blank Database
• To create a new blank database
– Click the New button
on the toolbar
– SelectBlank Database from the task pane
3. Creating a Blank Database
• Navigate to the drive and folder where
you want to save the new database, then
type a name for your new database in the
file name box
• Click create.
4. Creating a Table Using the Table
Wizard
• To create a new table using the table
wizard:
– In the database window, click the tables icon
in the objects bar and then double-click create
table by using wizard.
– Select the type of table you want to create.
– Follow the onscreen instructions and specify
what you want to appear in your database.
4. Creating a Table Using the Table Wizard
5. Modifying a Table and Understanding Data Types
• A table in Design view
5. Modifying a Table and Understanding Data Types
•
To display a table in design view:
– Open the table and click the view button on
the toolbar, or in the database window
– Click the tables icon in the objects bar,
select the table, and click the design button.
•
To change the data type for a field:
– Display the table in design view.
– Click the field's data type box, click the list
arrow, and select the data type from the list.
5. Modifying a Table and Understanding Data Types
Data Types
Data
Type
Example
Description
Text
Legal
Name:
John Doe
Stores
text,
numbers,
or
a
combination of both, up to 255
characters long. Text fields are the
most common of all data types.
Memo
Notes:
Sally
displays a
high amount
of...
Stores long text entriesup to 64,000
characters long (the equivalent of 18
pages of text!). Use memo fields to
store notes or anything else that
requires a lot of space.
Numbe
Age: 31
r
Stores numbers that can be used in
calculations.
5. Modifying a Table and Understanding Data Types
Date/Time
Birthday:April
7, 1969
Stores dates, times, or both.
Currency
Price: $84.95
Stores numbers and symbols that
represent money.
AutoNumb
er
Invoice
Number:
187001
Automatically fills in a unique
number for each record. Many
tables
often
contain
an
AutoNumber field that is also used
as their primary key.
Yes/No
Employed?:
Yes
Stores only one of two values,
such as Yes or No, True or False,
etc.
5. Modifying a Table and Understanding Data Types
OLE Object
Photo:
Hyperlink
Web Site:
www.amazon.c
om
Lookup
Wizard
Purpose of Trip
Stores objects created in
other programs such as a
graphic, Excel spreadsheet,
or Word document.
Stores clickable links to files
on your computer, on the
network, or to Web pages on
the Internet.
A wizard that helps you
create a field whose values
are selected from a table,
query, or a preset list of
values.
6. Creating a Query in Design View
• The Query window in Design view
The Query window in Design view
6. Creating a Query in Design View
• The design grid
•
To create a query in design view:
– In the database window, click the queries icon in the
objects bar and then double-click create query in
design view.
– Select the table you want to add to the query and
click add.
– Repeat step 2 as necessary for additional tables or
queries, and click close.
6. Creating a Query in Design View
– In the field list, double-click each field you
want to include in the query, or drag the field
from the field list onto the design grid.
– In the design grid, enter any desired search
criteria for the field in the criteria box.
– Uncheck the field's show box if you don't want
it to be displayed in the query results.
– Close the query window. Click yes to save the
query, enter a query name, and then click ok.
6. Creating a Query in Design View
Common Criteria Operators
Operator Example
Description
="MN"
Finds records equal to MN.
"MN"
Finds records not equal to MN.
<
<10
Finds records less than 10.
<=
<=10
Finds records less than or equal
to 10.
>
>10
Finds records greater than 10.
>=
>=10 AND 5
Finds records greater than or
equal to 10 and not equal to 5.
BETWEEN
BETWEEN
1/1/99 Finds records between 1/1/99
AND 12/31/99
AND 12/31/99.
=
LIKE
LIKE "S*"
Finds text beginning with the letter
"S." You can use LIKE with
wildcards such as *.
7. Modifying a Query
• To add a field to a query:
– In the field list, double-click each field you
want to include in the query, or drag the field
from the field list onto the design grid.
• To delete a query field:
– Click the top of the field you want to delete
and press delete.
• To rearrange fields:
– Position the pointer over the field and then
click and drag the field to a new location.
8. Sorting a Query Using Multiple Fields
• Example: Creating a sort that sorts by LastName,
then by FirstName
8. Sorting a Query Using Multiple Fields
• To sort a query using multiple fields:
– Open/display the query in design view.
– If necessary, add the field you want to use to
sort the query to the design grid.
– Click the sort box list arrow for the first field
you want to use to sort the query, then select
a sort order.
– Repeat steps 2-3 for each additional field you
want to use to sort the query, bearing in mind
that the fields will be sorted from left to right
9. Developing AND and OR
Operators
• Creating an AND statement
• Creating an OR statement
9. Developing AND and OR
Operators
• To create and/or criteria:
– Open/display the query in design view.
– Enter your criteria in the appropriate field's
first criteria box.
– Enter additional criteria as follows:
• And: enter additional criteria for one or
more fields in the appropriate field's criteria
box. All and criteria should appear on the
same row.
• Or: enter additional criteria for one or more
fields in the appropriate field's criteria box,
using a different row for each or criteria.
10. Creating a Form with the Form Wizard
• To create a form using the form wizard:
– In the database window, click the forms icon
in the objects bar and then double-click
create form by using wizard.
– Select the table or query you want to use to
create your form and select the fields that you
want to appear on the form. Click next when
you're finished.
– Select the type of form you want to create
and click next.
– Select a format for your form and click next.
– Give your form a name and click finish.
10. Creating a Form with the Form
Wizard
11. Creating a Report with the Report
Wizard
• To create a report using the report wizard:
– In the database window, click the reports icon in
the objects bar and then double-click create
reports by using wizard.
– Select the table or query you want to use to
create your report and select the fields that you
want to appear on the report. Click next when
you're finished.
– Select a field by which to group the report and
click next (optional).
– Specify the field(s) you want to use to sort the
report and click next (optional).
– Select a format for the report and click next.
– Give your report a name and click finish.
12. Creating Mailing Labels with the Label
Wizard
•
•
In the database window, click the reports icon in the
objects bar, click the new button on the toolbar,
select label wizard from the list and click ok.
Select the table or query you want to use to create
your labels and click ok.
12. Creating Mailing Labels with the Label
Wizard
• Select the product number for your Avery labels
12. Creating Mailing Labels with the Label
Wizard
•
Select the fields that you want to appear on the
report and enter any text. Click next when
you're finished.
13. Database Object Management
• To cut/copy and paste a database object:
– Select the database object.
– Click the cut or Click the copy button on the
toolbar.
– Click the paste button on the toolbar, enter a
name for the new object, and click ok.
• To rename an object:
– Right-click the object, select rename from the
shortcut menu, and enter a new name for the
object.
• To delete an object:
14. Compacting and Repairing a Database
• Compact Database: Compacting a database
rearranges how the database is stored and
reduces its file size.
• Repair Database: Over time, normal wear and
tear causes errors to appear in your database,
thus affecting its performance
• Select tools database utilities compact and
repair database from the menu