| Oracle® Database Express Edition 2 Day Plus Application Express Developer Guide Release 2.1 Part Number B25310-01 |
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View PDF |
| Oracle® Database Express Edition 2 Day Plus Application Express Developer Guide Release 2.1 Part Number B25310-01 |
|
|
View PDF |
Data and form elements in an Oracle Application Express application are placed on a page using containers called regions. There are several attributes that control the placement and positioning of regions on pages. In turn, you control the placement and style of form elements inside of regions using item attributes.
This tutorial describes how to create a data input form and then change its layout by changing region and item attributes.
This section contains the following topics:
Application Builder installs with a number of demonstration applications. In this exercise you create a data input form within the demonstration application, Sample Application.
To see if Sample Application is installed:
Log in to the Database Home Page using your database username and password.
Click the down arrow on the right side of the Application Builder icon.
From the menu, select Demonstrations.
The Demonstration Applications page appears, displaying links to demonstration applications.
Locate Sample Application and check the Status column:
If the Status column displays Installed, return to the Database Home Page.
If the Status column displays Not Installed, select Install in the Action column. Follow the on-screen instructions.
The first step in creating a data input form is to create the underlying data objects in SQL Scripts. In this exercise, you create a table named HT_EMP and then use a wizard to create a new page.
Topics in this section include:
First, you create a new table by running a script in SQL Scripts.
To create the HT_EMP table and the appropriate associated objects:
On the Database Home Page, click the SQL icon.
Click SQL Scripts.
When the SQL Scripts appears, click Create.
The Script Editor appears.
In Script Name, enter HT_EMP.
In the Script Editor, enter the following DDL:
CREATE TABLE ht_emp (
emp_id NUMBER primary key,
emp_first_name VARCHAR2(30) not null,
emp_middle_initial VARCHAR2(1),
emp_last_name VARCHAR2(45) not null,
emp_part_or_full_time VARCHAR2(1) not null check (emp_part_or_full_time in ('P','F')),
emp_salary NUMBER,
emp_dept VARCHAR2(20) check (emp_dept in ('SALES','ACCOUNTING',
'MANUFACTURING','HR')),
emp_hiredate DATE,
emp_manager NUMBER references ht_emp,
emp_special_info VARCHAR2(2000),
emp_telecommute VARCHAR2(1) check (emp_telecommute in ('Y')),
rec_create_date DATE not null,
rec_update_date date)
/
INSERT INTO ht_emp
(emp_id, emp_first_name, emp_middle_initial, emp_last_name, emp_part_or_full_time,
emp_salary, emp_dept, emp_hiredate, emp_manager, emp_special_info, emp_telecommute,
rec_create_date)
VALUES
(1,'Scott','R','Tiger','F',
100000,'SALES',sysdate,null,'cell phone number is xxx.xxx.xxxx
home phone is yyy.yyy.yyyy','Y',
SYSDATE)
/
CREATE SEQUENCE ht_emp_seq
start with 2
/
CREATE OR REPLACE TRIGGER bi_ht_emp
BEFORE INSERT ON ht_emp
FOR EACH ROW
BEGIN
SELECT ht_emp_seq.nextval
INTO :new.emp_id
FROM DUAL;
:new.rec_create_date := SYSDATE;
END;
/
CREATE OR REPLACE TRIGGER bu_ht_emp
BEFORE UPDATE ON ht_emp
FOR EACH ROW
BEGIN
:new.rec_update_date := SYSDATE;
END;
/
Click Save.
The script appears in the SQL Scripts Repository.
Run the HT_EMP script:
Click the HT_EMP script.
Click Run.
On the Run Script page, click Run again.
Next, change the page view to Details.
From the View list, select Details and click Go.
Figure 4-1 Details View in the Manage Script Results Page
Click the View icon to access the Results page.
Red text indicates errors while executing the file.
See Also:
"Using SQL Scripts" in Oracle Database Express Edition Application Express User's Guide.Next, create a new form using the Form on a Table or View Wizard.
To create a data input form:
Navigate to the Database Home Page by clicking the Home breadcrumb link at the top of the page.
Click the Application Builder icon.
Select Sample Application.
Click Create Page.
For Page, select Form and click Next.
On Create Page, select Form on a Table or View and click Next.
For Table/View Owner, accept the default and click Next.
For Table/View Name, select the HT_EMP table and click Next.
For Page and Region Attributes:
In Page, enter 900.
In the Page Name, enter HT_EMP.
In the Region Title, enter How to Layout a Form.
For Region Template, accept the default.
Click Next.
For Tab, accept the default, Do not use tabs, and click Next.
For Primary Key, accept the default and click Next.
Note that the wizard reads the primary key from the database definition.
For Source Type, accept the default Existing Trigger and click Next.
For Select Columns, press SHIFT, select all columns, and click Next.
For Process Options, accept the defaults and click Next.
For Branching, in the fields provided enter 900 (the page you are creating) and click Next.
Since this page is just for demonstration, you will not be utilizing branching.
Click Finish.
View the Page Definition by clicking the Edit Page icon.
The Page Definition for page 900 appears.
Delete the following validation:
Under Page Processing Validations, select P900_REC_CREATE_DATE not null.
Click Delete.
Once you create the HT_EMP table and page 900, the next step is to run the page.
To run the page from the Page Definition:
Click the Run Page icon in the upper right corner as shown in Figure 4-2.
If prompted to enter a username and password:
For User Name, enter either demo or admin.
For Password, enter the name of your database user account in all lowercase letters.
Click Login.
Sample Application appears.
Navigate to page 900:
Click Edit Page 1 on the Developer toolbar at the bottom of the page.
The Page Definition appears.
In the Page field, enter 900 and click Go.
On the Page Definition for page 900, click the Run Page icon in the upper right corner.
As shown in Figure 4-3, the new form appears. Note that the HT Emp form contains basic employee details and includes select lists, text areas, and display only items.
By default, the Primary Key column does not display since it is assumed that the primary key is system generated. In reality, the primary key is included in the page, but appears as a hidden item.
Notice that the page defaults with one item for each row and labels display to the left of the items. The item labels default to the column names with initial capitalization and with the underscores (_) replaced with spaces. You can override this default behavior by configuring user interface defaults for the table.
See Also:
"Managing User Interface Defaults" in the Oracle Database Express Edition Application Express User's Guide.Also notice that items based on date columns default to include a date picker. Lastly, notice that the Emp Special Info item was created as a text area because of the size of the base column. This item type is a better choice for large text items since it allows for wrapping of input text.
A region is a area on a page that serves as a container for content. You can alter the appearance of a page by changing the region attributes.
To change the region title and other region level attributes:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Regions, click How to Layout a Form as shown in Figure 4-4.
The Region Definition appears.
Change the Title to Employee Info.
Scroll down to User Interface.
From Display Point, temporarily move the region by selecting Page Template Region Position 3.
The Display Point controls the position of a region within the page template. In this instances, your selection moves the region to the right side of the page. The region display points are determined by the page level template. If you do not select a page level template, Application Express engine uses the default page level template defined in the current theme. You can view specific positions by selecting the flashlight icon to the right of the Display Point list.
Next, temporarily change the region template.
From Template, select Borderless Region.
Click Apply Changes at the top of the page.
From the Page Definition, click the Run Page icon in the upper right corner.
The form appears as shown in Figure 4-5.
Figure 4-5 HT_EMP Form with New Display Point and Template
To return the region template and display point to the original selections:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Regions, select Employee Info.
Scroll down to User Interface.
From the Template list, select Form Region.
From the Display Point List, select Page Template Body (3. Items above region content).
Click Apply Changes at the top of the page.
An item is part of an HTML form. An item can be a text field, a text area, a password, a select list, a check box, and so on. Item attributes control the display of items on a page. Item attributes determine where a label displays, how large an item will be as well as whether the item displays next to or below a previous item. You can change multiple item labels at once on the Page Items summary page.
Topics in this section include:
See Also:
"Creating Items" in Oracle Database Express Edition Application Express User's Guide.To edit item attributes:
Navigate to the Page Definition for page 900.
On the Page Definition, select the title Items.
The Page Items summary page appears.
You change how a page appears by editing the item attributes. Common item attribute changes include:
Changing item labels by editing the Prompt field.
Placing more than one item in certain rows to group like items together. For example, you could group all items that make up an employee's name.
Changing the item width. Many items display better when they have a width that is less than the maximum. To change the item width, enter a new value in the Width field.
Reordering the items. The initial order of items is based on the order of the columns in the table on which the region is based. You can reorder items by changing the sequence. You can reorder items by entering a new value in the Sequence field.
To see the how item attributes affect page layout, make the following changes:
Change the values in the Prompt, New Line, and Width fields to match those in Table 4-1:
Table 4-1 New Prompt, New Line, and Width Field Values
| Prompt Field | New Line | Width |
|---|---|---|
|
Emp ID |
Yes |
30 |
|
First Name |
Yes |
15 |
|
Middle Initial |
No |
2 |
|
Last Name |
No |
15 |
|
Part or Full Time |
Yes |
2 |
|
Salary |
Yes |
10 |
|
Department |
Yes |
15 |
|
Hire Date |
Yes |
10 |
|
Manager |
No |
15 |
|
Special Information |
Yes |
60 |
|
Telecommute |
Yes |
2 |
|
Record Create Date |
Yes |
10 |
|
Record Update Date |
Yes |
10 |
Click Apply Changes.
Click the Run Page icon in the upper right corner of the page. (See Figure 4-6.)
Figure 4-6 HT_EMP After Editing the Prompt, New Line, Width Attributes
Note that some items are pushed too far to the right. This display is caused by the width of the Special Information item. Oracle Application Express lays out regions as tables and of a width of each column is determined by the largest display width of the items in that column.
There are several approaches to fixing item alignment:
For the items Middle Initial, Last Name and Manager items, set New Field to equal No.
This places the items directly after the items they follow, but in the same column. This approach is best used for positioning embedded buttons next to items. Note that this setting can make text items appear squashed.
Change the Column Span field of the Special Information item.
For example, setting the Column Span for the Special Information item to 5 would enable multiple items to display above and below it. This change causes five items to display above Special Information (First Name, Middle Initial, and Last Name).
Be aware, however, that using Column Span to fix the display of the name does not result in a consistent layout. The Manager item would still be in the same column as Middle Initial. Because the Manager item is larger than Middle Initial, Last Name would still be pushed too far to the right. To fix this, you could change the Column Span of the Manager item to 3 so it displays above Special Information.
Reset the column width in the middle of the region by adding an item of type Stop and Start HTML Table. This forces the close of an HTML table using the </table> tag and starts a new HTML table. Inserting a Stop and Start HTML Table item just after the Last Name item, results in an even layout. Note that a Stop and Start HTML Table item only displays its label. You can prevent the label from displaying at all by setting it to null. To do this, you simply remove the defaulted label.
To add a Stop and Start HTML Table item and reset the column width:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Items, click the Create icon as shown in Figure 4-7.
For Item Type, select Stop and start table and click Next.
The Create Item Wizard appears.
For Display Position and Name:
For Item Name, accept the default.
In Sequence, enter 4.5.
From Region, select Employee Info.
Click Next.
On Item Attributes:
Remove the X in the Label field by clicking Clear.
Accept all other defaults and click Next.
Click Create Item.
The Page Definition appears.
Edit the column width for Special Information:
Click the title Items.
For Special Information, change the Column Span to 3 and click Apply Changes.
Click the Run Page icon in the upper right corner.
There are two columns in the HT_EMP table for auditing, Record Create Date and Record Update Date. Because the values of these columns are set with triggers, these columns should not be updatable by users. This exercise describes how to make items display-only and then how to add them to their own region.
To make an item P900_REC_CREATE_DATE display-only:
Navigate to the Page Definition for page 900.
Under Items, select the item P900_REC_CREATE_DATE.
From Display As, select Text Field (Disabled, saves state).
Click Apply Changes.
To make an item P900_REC_UPDATE_DATE display-only:
Navigate to the Page Definition for page 900.
Under Items, select the item P900_REC_UPDATE_DATE.
From Display As, select Text Field (Disabled, saves state).
Click Apply Changes.
Next, create a new region and then move the audit items into that region.
To create a new region:
Navigate to the Page Definition for page 900.
Under Regions, click the Create icon as shown in Figure 4-8.
For the region type, select HTML and click Next.
Specify the type of region container. Select HTML and click Next.
For the Title, enter Audit Information, accept the remaining defaults, and click Next.
Click Create Region.
To move the items to the new region:
Navigate to the Page Definition for page 900.
Select the heading Items.
A summary page appears.
For P900_REC_CREATE_DATE and P900_REC_UPDATE_DATE:
Under Prompt, add a colon to the end of the label name.
Under Region, select Audit Information.
Click Apply Changes.
Click the Run Page icon in the upper right corner.
Figure 4-9 demonstrates how these items would display in a running page.
The Hide/Show Region template enables the user to click a plus (+) sign to expand the contents of the region or click a minus (-) sign to hide the contents. By changing the region template to Hide/Show Region, users can decide whether they want to see the Audit Information region.
To change the region template to Hide/Show Region:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Regions, select Audit Information.
Scroll down to User Interface
From the Template list, select Hide and Show Region.
Click Apply Changes.
Regions can have headers and footers. Headers and footers typically contain text or HTML that displays at either the top or bottom of the region.
To add a region footer:
Navigate to the Page Definition for page 900.
Under Regions, select Audit Information.
Scroll down to Header and Footer.
Enter the following in Region Footer:
<i>The Record Create Date is the date that the record was initially entered in to the system. <br>The Record Update Date is the date that the record the record was last updated.</i>
Click Apply Changes.
Run the page by clicking the Run Page icon in the upper right corner.
Expand the Audit Information region as shown in Figure 4-10.
Figure 4-10 Audit Information Region with Footer
As shown in Figure 4-10, the text of the footer is wrapped with the italic HTML tag and there is an imbedded a break. Without the manual break, the text would take up the entire width of the region (as defined by region template).
To make a region conditional you create a display condition for the Audit Information region so that it only displays if the Employee ID is not null. Since the Employee ID is set by a trigger, it only exists for records retrieved from the database. You can control the display of the Audit Information region by using a built-in condition that checks for the presence of a value for the item containing the Employee ID (that is, P900_EMP_ID)
To display the Audit Information region conditionally:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Regions, select Audit Information.
When the Region Definition appears, scroll down to Conditional Display.
Under Conditional Display:
From Condition Type, select Value of Item in Expression 1 is NOT NULL.
In Expression 1, enter:
P900_EMP_ID
Click Apply Changes.
You have the option of displaying regions in columns as well as in rows. This exercise explains how to create another region to display hint text to the user.
To create a region to display hint text:
Navigate to the Page Definition for page 900.
Under Regions, click the Create icon.
For the region type, select HTML and click Next.
Select the type of HTML region container. Select HTML and click Next.
For Display Attributes:
In Title, enter Hint.
From Region Template, select Sidebar Region.
From Display Point, select Page Template Region Position 3.
For Sequence, accept the default.
From Column, select 3.
Click Next.
In Enter HTML Text Region Source, enter the following:
Use this page to enter and<br/> maintain employee information.
Click Create Region.
Click the Run Page icon. Note the new region on the left of the page as shown in Figure 4-11.
This exercise describes how to change item types to make data entry easier for the user. To change an item type, navigate to the Item attributes page and select another Display As option.
Topics in this section include:
Because the Part or Full-time item only has two valid choices, this item is a good candidate for either a check box or a radio group.
To change the Part or Full-time item to a radio group:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Items, select P900_EMP_PART_OR_FULL_TIME.
From Display As, select Radiogroup.
Scroll down to Label. For Label, remove the label text. (It will be redundant.)
Scroll down to List of Values.
Under List of Values, create a static list of values:
From Named LOV, select Select Named LOV.
In List of values definition, enter:
STATIC:Full-time;F,Part-time;P
This definition will display as two radio buttons with the labels Full-time and Part-time, but the value that being inserted into the database will be either F or P.
Scroll back to the top of the page.
Click Apply Changes.
Run the page by clicking the Run Page icon in the upper right corner. The modified form appears as shown in Figure 4-12.
Figure 4-12 Part or Full-time item Changed to a Radio Group
Notice that Full-time and Part-time displays as radio group that is stacked in one column. You can have these button display side by side.
To display the Full-time and Part-time radio buttons display side by side:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Items, select P900_EMP_PART_OR_FULL_TIME.
Scroll down to Lists of Values.
In Columns, enter 2.
Scroll up to the top of the page and click Apply Changes.
By changing this setting to match the number of valid values (that is, Full-time and Part-time), the values display side by side.
In the DDL you used to create the HT_EMP table, Department is validated by a check constraint. You can implement Department as a radio group, a select list, or a Popup LOV.
To change Department to a select list:
Navigate to the Page Definition for page 900.
Under Items, select P900_EMP_DEPT.
From Display As, select Select List.
The other Select List choices are for either redirecting the user to another page or URL based on the selection, or submitting the current page which is used when other information needs to be retrieved based upon the selection in the Select List.
Scroll down to Lists of Values.
Under Lists of Values, create a static list of values:
From Named LOV, select Select Named LOV
In List of values definition, enter:
STATIC:SALES,ACCOUNTING,MANUFACTURING,HR
From Display Null, select Yes.
In Null display value, enter:
- No Assignment -
The last two selections take into account that the EMP_DEPT column can contain nulls. As a best practice, whenever you implement a select list and have a column that can be null, you should set Display Null to Yes. Failure to do so, results in the item defaulting to the first item in the select list.
Scroll up to the top of the page and click Apply Changes.
Run the page by clicking the Run Page icon.
The revised form appears as shown in Figure 4-13.
Figure 4-13 Department Changed to a Select List
The item Telecommute is ideal for a check box. When you change the Display Type, you can also move it up on the page and place is next to the Full-time and Part-time radio group.
To change Telcommute to a check box:
Navigate to the Page Definition for page 900. Click Edit Page 900 on the Developer toolbar.
Under Items, select P900_EMP_TELECOMMUTE.
From Display As, select Checkbox.
Under Displayed:
In Sequence, enter 55.
From Begin on New Line, select Yes
Scroll down to List of Values.
To have the label precede the check box:
From Named LOV, select Select Named LOV
In List of values definition, enter:
STATIC:;Y
This List of values definition displays the check box after the label, but will not display a value associated with the check box. If the check box is checked, the value passed to the database will be Y.
Scroll up to the top of the page and click Apply Changes.
Run the page by clicking the Run Page icon.
You can control the look of an item label by using a label template. Sample Application includes the following label templates:
No Label
Required Label
The Required Label template prepends a red asterisk (*) to the label. You may also create your own label templates to control the look of labels using different fonts, borders, backgrounds, and images.
To change to a different label template:
Navigate to the Page Definition for page 900.
Under Items, select an item name.
Scroll down to Label and make a selection from the Template list.
Click Apply Changes.
Run the page.
The wizard that created the form in this tutorial also created buttons. These buttons display conditionally based upon whether the page is being used to create a new record (that is P900_EMP_ID equals null), or the page is being used to update an existing record. These buttons were created as HTML buttons and positioned at the top of the region.
You can also position buttons at the bottom of the region, to the left or right of the page title, above the region, below the region, or in any button position defined in the region template.
To change a button position:
Navigate to the Page Definition for page 900.
Click the heading Buttons.
Make a new selection from the Position column.
Click Apply Changes.
Run the page.
Buttons can also have templates associated with them to refine how they look.
You can run the page and provide it with an Employee ID to retrieve. Typically, this would be done with a link from a report page but for this example, run the page and add ::::P900_EMP_ID:1 to the end of the URL as shown in the following example:
http://apex.oracle.com/pls/otn/f?p=9659:900:1284393467360777225::::P900_EMP_ID:1
This will pass the value 1 to the item P9000_EMP_ID. If you run the page note that the Delete and Apply Changes buttons now display. The Create button appeared previously because the page was expecting a new record to be created. Also note a Record Create Date now appears.
See Also:
"Understanding URL Syntax" in Oracle Database Express Edition Application Express User's Guide.One way to make the information in a region easier to read, is to make the labels (or the data) more pronounced. You can accomplish this by changing the color, specifying another font, or using bold. To make a label bold, you could bold the data manually, or create a new label template. In the latter approach, you would create a new label template that would wrap the HTML tag for bold around the label and then associate that template with the items in the Audit Information region.
To make data bold manually:
Navigate to the Page Definition.
Under Items, select an item name.
Scroll down to Element.
In HTML Form Element Attributes, enter:
class="fielddatabold"
This example references a class in the Cascading Style Sheet associated with this application.
Click Apply Changes.
Run the page.
