Introduction

For more information: You can also work with ObjectStore collections using the instance pane of the main database view window. See Chapter 5, Classes and Instances.

In this chapter

• Overview
• Working With Data Views
• Filtering a Collection
• Ordering a Collection

A Data View Contrasted to the Instance Pane

Think of a data view as an instance pane with its own window.

A data view is similar to the instance pane in that you can choose to display information using a collection grid or a collection list. Only data views, however, allow you to manipulate the ObjectStore collection data itself. Consider creating a data view any time you want to

• Filter ObjectStore collection instances. Filters are described in Filtering a Collection.
• Control the order of ObjectStore collection instances. Ordering features are described in Ordering a Collection.

Features for Changing Collection Grid Appearance

• Change the alignment of data in a cell
• Enhance the cell border
• Add shading and color to the cell background
• Change the font used to display data
• Specify the format used to display numbers
• Annotate using text and shapes
• Apply formulas
• Save customized grids

Working With Data Views

Creating a Data View

How to create

1. Display the main database view window.
   
   
2. Populate the instance pane with an ObjectStore collection.
   
   If you need help with this step, see Populating Collection Grids and Lists.

3. Click Data View | Create on the menu bar.
   
   Alternative: Select Create Data View from the instance pane shortcut menu.

   A data view window appears. The title bar displays the

   • Collection address
   • Number of elements in the collection
   • The class associated with the collection
     
     Tip: When you save a data view, you can give it a name. The name you assign replaces the address; element and class information is retained in the title bar.

4. At this point, you can either save the data view, or begin customizing its layout or contents as described in the remaining sections of this chapter.
   
   

To create a data view of this type:

1. Display the Instance Window for the class that contains the data member.
   
   
2. Right click on the data member. A shortcut menu appears.
   
   
3. Select Create Data View from the shortcut menu.
   
   A data view window appears, listing the data in the array.

To create a data view of this type:

1. Right click on the class in the Schema Pane.
   
   
2. Select User-defined Methods | Extent from the shortcut menu and then select the user-defined method.
   
   

In order to use a user-defined method in this way, it must be registered. For more information about defining and registering user-defined methods, see Chapter 7, User-Defined Methods.

Saving a Data View

How to save

1. Click File | Save on the menu bar.
   
   Alternative: Click the Save tool on the data view window's toolbar.

   The Save Data View dialog box appears.

2. Type a name in the Data View Name field and click OK.
   
   Tip: Give the data view a name that will help you remember its characteristics should you want to open it at a later time.

   The data view is saved with the name you give it. It is available any time you open the current database in Inspector.

To open a data view:

1. Click Data View | Open on the menu bar.
   
   The Open Data View dialog box appears.

   Tip: The Open Data View dialog box is similar to the Save Data View dialog box.

2. Select the data view you want to open from the list box and click OK to open it.
   
   Alternative: Double-click the data view.

   The data view window appears.

1. Click Data View | Delete on the menu bar.
   
   The Delete Data View dialog box appears.

   Tip: The Delete Data View dialog box is similar to the Save Data View dialog box.

2. Select the data view you want to delete from the list box and click the Delete button to delete it.
   
   Alternative: Double-click the data view.

   The data view window is deleted.

One filter for a data view

Filter constraints

Providing parameterized constraint values

• Enter his or her own value
• Select from a list of values - either collection values for that data member or values defined for the constraint

Regardless of which method you use, Inspector displays the Fill Query Parameters dialog box when the filter is applied to the ObjectStore collection.

See Defining Parameterized Constraints for more information.

Two Ways to Define a Filter

• You can define the filter manually, using the Set ObjectStore Query Expression dialog box. This method requires command of the ObjectStore query syntax and should be considered only by advanced users of ObjectStore. See Defining a Filter Manually for more information. Note: Once you define a filter manually, you cannot use the Data Member Constraints dialog box to build a filter for that data view.

• You can use the Data Member Constraints dialog box. This tool allows you to build the filter query expression using Inspector's graphic interface. You construct the query constraint by constraint, identifying the data members, operators, and values you want the query to include. See Defining a Filter Using Inspector.

  Parameterized constraints are also defined using a graphic interface - one dialog box to help you construct the constraint, and another that appears at run time so you can provide the parameter value.

• Use a regular expression parser
• Run parametric queries
• Query data members of subclasses
• Navigate os_references recognized as relationships
• Navigate Java references and collections

When Are Filters Applied?

How to turn filters on and off

To turn a filter on and off, click Data View | Filter On on the menu bar, or click the Toggle Filter tool on the data view window toolbar.

Tip: A filter is on when a check mark appears alongside Filter On on the Data View menu, or when the Toggle Filter tool is selected.

How to reapply a filter

• If you know an application has changed instances in the ObjectStore database
• If the filter contains parameterized constraints and you want to run the filter with new constraint values

Defining a Filter Manually

You use the Set ObjectStore Query Expression dialog box to manually define collection filters.

If you are not familiar with ObjectStore query syntax, use Inspector to define the filter. See Defining a Filter Using Inspector.

How to use

1. Click Data View | Set Filter Expression on the menu bar.
   
   
2. Enter the query expression - you must use ObjectStore query syntax.
   
   
3. Click OK to create the filter.
   
   

You use the Data Member Constraints dialog box when you want Inspector to help you define a filter.

How to open

Usage tips

• The Data Member list box displays the data members of the collection's instances. You can also include data members of navigable classes.
• The Operator drop-down list box contains a list of standard query operators: greater than (>), not equal to (!=), and so on.
• The Data Member field lets you define a static constraint value. Other options appear below this field based on the type of the data member you select.

• Defined as part of the database,
• Created by Inspector

Displaying the filter query

To display a translated filter query, click Data View | Show Filter Expression on the menu bar.

Tip: If you are defining filters manually, you can use the Copy button to copy query elements to the clipboard for pasting.

Definition process

Defining Parameterized Constraints

You define a parameterized constraint using the Parameter Definition dialog box.

Note that the fields in this dialog box vary based on whether you are defining a parameterized constraint for string or integer types. The dialog box shown here is for string types.

How to define a parameterized constraint for string types

1. Follow the procedure for defining a filter as described in Definition process.
   
   
2. At step 3 of that process, select the data member with which you want to associate the parameterized constraint from the Data Member list box and click the Define Parameterized Constraint button.
   
   The Parameter Definition dialog box appears.

3. Enter text in the User Prompt field for the prompt you want to appear in the Description field of the Fill Query Parameters dialog box.
   
   
4. Select the comparison value you want to use for this data member.
   
   
5. In the Control group box, select the type of control for the Value field of the Fill Query Parameters dialog box:
   
   
   • List box
   • Drop-down list box
   • Edit box Tip: If you use the edit box control, the user must provide his or her own value at run time.

6. Optionally, name the parameter.
   
   
7. Are you using an edit box control for the Value field of the Fill Query Parameter dialog box?
   
   If yes, you are done defining the parameterized constraint. Go to step 13.

   If no, go to step 8.

8. Click the Multiple Selection and Sort check boxes if you want to enable this functionality in the Value field.
   
   
9. Do you want the user to select from a list of actual data members to provide the parameter value?
   
   If yes, click Get Values From Query and go to step 13.

   If no, go to step 10.

10. Click Enter Values By Hand and go to step 11.
    
    
11. Define the list of parameter values from which you want the user to be able to select:
    
    
    1. Type a name in the New Value field.
       1. Click Add to place the value in the Defined Values list box. Tip: Click Remove to remove a value from the Defined Values list box.

12. Select the Always Recompute Values check box if you want Inspector to refresh the collection each time the filter is applied.
    
    
13. Click OK to return to the Data Member Constraints dialog box.
    
    
14. Go to step 2 if you want to define a parameterized constraint on another data member in the filter. Otherwise, click OK to finish defining the filter.
    
    The filter is applied to the collection. Inspector displays the Fill Query Parameters dialog box. See Using the Fill Query Parameters dialog box.

1. Follow the procedure for defining a filter as described in Definition process.
   
   
2. At step 3 of that process, select the data member with which you want to associate the parameterized constraint from the Data Member list box and click the Define Parameterized Constraint button.
   
   The Parameter Definition dialog box appears.

3. Enter text in the User Prompt field for the prompt you want to appear in the Description field of the Fill Query Parameters dialog box.
   
   
4. Select the operator you want to use for this data member.
   
   
5. Select the type of control for the Value field of the Fill Query Parameters dialog box from the Control drop-down list box:
   
   
   • Drop-down list box
   • Edit box Tip: If you use the edit box control, the user must provide his or her own value at run time.

6. Optionally, name the parameter.
   
   
7. Are you using an edit box control for the Value field of the Fill Query Parameter dialog box?
   
   If yes, you are done defining the parameterized constraint. Go to step 10.

   If no, go to step 8.

8. Define the list of parameter values from which you want the user to be able to select:
   
   
   1. Type a name in the New Value field.
      1. Click Add to place the value in the Defined Values list box. Tip: Click Remove to remove a value from the Defined Values list box.

9. Select the Always Recompute Values check box if you want Inspector to refresh the collection each time the filter is applied.
   
   
10. Click OK to return to the Data Member Constraints dialog box.
    
    
11. Go to step 2 if you want to define a parameterized constraint on another data member in the filter. Otherwise, click OK to finish defining the filter.
    
    The filter is applied to the collection. Inspector displays the Fill Query Parameters dialog box. See Using the Fill Query Parameters dialog box.

If you defined a parameterized constraint for one of the data members included in the filter, Inspector displays the Fill Query Parameters dialog box when the filter is applied to the collection.

To complete the dialog box:

1. Double-click the Value field.
   
   The Value field becomes editable, displaying the type of control you defined for it.

2. If the control is a type of list, select the values from the list. Otherwise, type a value in the field.
   
   
3. If necessary, go to step 1 for any other parameterized constraints that are defined for this filter.
   
   
4. Click OK to close the dialog box and complete the filter.
   
   Inspector redisplays the collection within the data view. The values displayed are based on the filter just applied to the collection.

5. To redisplay the entire collection, turn off the filter.
   
   

In addition to filtering an ObjectStore collection, you can order an ObjectStore collection based on the values of one of the data member's instances. You use the Sort Order dialog box to define a collection order.

Selecting Data Members

• Defined as part of the database, or
• Created by Inspector

When Does the Order Take Effect?

How to turn orders on and off

To turn a collection order on and off, click Data View | Collection On on the menu bar, or click the Toggle Order tool on the data view window toolbar.

Tip: A collection order is on when a check mark appears alongside Order On on the Data View menu, or when the Toggle Order tool is selected.

How to Define a Collection Order

1. Click Data View | Define Order on the menu bar.
   
   The Sort Order dialog box appears

2. Select the data member on whose instances you want to order the collection.
   
   
3. Click the Ascending or Descending radio button to determine the collection order.
   
   
4. Click OK.
   
   The collection is redisplayed based on the order you just defined.

   Note: The collection's original order is restored when you turn the order off.

Updated: 05/07/99 16:42:44