Function Executor runs on Windows. With this interactive tool, you can learn how Btrieve operations work. Btrieve operations are the same as MicroKernel Engine operations.
By allowing execution of Btrieve operations one at a time, Function Executor enables application developers to simulate the operations of a Btrieve application. This simulation can isolate the database calls from the rest of your application, which can help in testing and debugging your program.
Function Executor is primarily a tool for application developers. This chapter assumes that you have a basic knowledge of Btrieve operations. For more information about Btrieve operations, refer to the Btrieve API Guide that is available in the Developer Reference.
What Function Executor Can Do
•Perform Btrieve operations while monitoring the contents of memory structures.
•Allow you to capture a series of Btrieve operations and save them as a history file for later playback
•Display the Btrieve version for clients, and local and remote engines.
•Display the Btrieve characteristics of data files and allow you to save those characteristics as a template (description file) or create a new file based on those characteristics. See File Statistics for more information.
The last/current status code is shown in the editor window’s status bar at the bottom of the window for the open file, and appears red if the last status was not zero.
Placing the mouse cursor over the status code shows a description of the status and what operation caused it. You can also click the display in red in order to display the full help for the status code. See To get help for a status code for more information.
When your cursor is in the input area on the main window of Function Executor, the status bar displays the offset within the buffer: the hex, the decimal, and the ASCII value of the byte you are presently on.
The status bar also indicates how many operations have been performed when there are multiple items in the queue. Normally this displays 1 of 1, but if you are executing multiple operations, it will display the count as the operations are executed.
The status bar also displays when you are in a transaction.
Statistics
Clicking the File Statistics icon displays a dialog box listing statistics for the currently open file. You can print these statistics to a text file or save them to a description file usable by a butil -create command. You may also create a new blank file with the same characteristics.
Get and GetExt
From the Get menu, you can retrieve the First, Next, Previous, and Last records in the table. The GetExt menu includes the Goto Percent, Get Position, and Find Percent commands.
The Get and GetExt commands are available from both the menu bar and toolbar. The toolbar offers Step (Physical) and Get (Logical), allowing you to move either through the natural order of the file (physical) or in a specific order (logical).
Goto Percent allows you to choose whether to jump to a point within the physical layout of the file, or down any key path, limited to the keys defined in the file. You can also set lock biases using the option buttons in the Locks group box.
Find Percentage is the opposite of Goto Percent. It tells you how far into the data you are, depending on whether you are stepping through the file logically or physically.
Transaction Toolbar
The Transaction toolbar lets you start, stop, and abort transactions. You can set all aspects of the Transaction API through this toolbar, and the operation is executed immediately. The Transaction status also appears on the main window status bar, since it affects all open files for the client ID.
Login Dialog
The Login dialog box allows you to perform the Btrieve login operation via a GUI interface. For more information, see topics about database security and its configuration.
History Log
When you perform operations using the Function Executor tool, they are recorded in a History log. You can use this log to perform the operations contained therein, or save the history as a file that you can later reload and step through.
See the following topics for more information about the History log:
When a file is open, you can right-click any position in the buffer and select Show As. A dialog box appears in which you can view the bytes at the chosen buffer position as any data type.
Table 57 lists controls available Function Executor.
Table 57 Function Executor Controls
Control
Description
Repeat
Allows you to repeat commands.
Create
Allows you to create a new file.
File Statistics
Gives information from the BSTAT function. You can print these statistics.
MDI
The Multiple Document Interface permits the opening of multiple files.
Reset
Reset Client ID
Stop
Btrieve Stop
Version
Btrieve Version
Automatic Mode in Function Executor
For each open file (see Application Window), you have the option of performing Btrieve operations with or without the assistance of Function Executor. You do not need to make any configuration changes to use one method or the other. Whether you use automatic mode or manual mode depends on which GUI controls you use.
Figure 9 Automatic Mode and Manual Mode Controls
Note Selections from the menus (see Application Window) also are part of the automatic mode.
When you click a button in the automatic mode area, the following assistance is provided by the tool:
•Data buffers and data lengths are set automatically to prevent status code 22.
•Information is requested appropriate to the operation.
Where to Learn More
Function Executor is a valuable tool for program developers, but it assumes you have a working knowledge of Btrieve fundamentals. See the following topics to understand all of the features of this tool:
•MicroKernel Engine fundamentals in Zen Programmer’s Guide
•Btrieve API Guide
•Various security topics in the advanced user documentation
Function Executor Graphical User Interface
This topic describes the objects on Function Executor graphical user interface (GUI).
Resets the current client connection (Btrieve operation 28) and closes all files opened with that client ID.
Stop
Ends transactional operations (Btrieve operation 25) and closes all open files.
Statistics
Displays a dialog box listing the currently opened file’s statistics. You can print these statistics to a text file or save them to a description file usable by BUTIL -CREATE
Version
Displays information about the version of Zen (using Btrieve operation 26) that you are running. If no file is open, you will see information about the requester DLLs and any local MicroKernel engine. If you open a file on a remote server, you will see information about the server and requester DLLs.
Status Codes Help
If no file is open, displays Status Codes help file.
If file is open and a status code is active, displays help for that particular status code.
Show help
Toggles whether a pop-up dialog box displays when a non-zero status code is received.
Specifies a data value. For read and write operations, the Data Buffer contains records. For other operations, the Data Buffer contains file specifications, filtering conditions, and other information the database engine needs for processing the operation. This control corresponds with the Data Buffer parameter.
Key Buffer
Specify the path for the data file for which you want to perform a Btrieve operation.
Sets or positions at a previously defined bookmark.
Key Num
For most Get operations, specifies a key number, or index path, to follow for the current operation. For other operations, specifies such information as file open mode, encryption, or logical disk drive. This control corresponds with the Key Number parameter.
Key Only
Specifies to get key only, not data.
Repeat
Repeats the operation the number of times you specify.
Locks
Specifies the locking behavior you want in for the current operation.
Op Code
Specifies the current operation code plus its bias (if any). The default is 0. If you are familiar with Btrieve operation codes, you can enter the desired code. Otherwise, use the List box to specify an operation. This control corresponds with the Operation Code parameter.
Lists all Btrieve operations and their codes. The default is Open (0). You can move quickly through the list by entering the first letter of the operation you want to perform.
Specifies the length (in bytes) of the Data Buffer. The default is 1024. For every operation that requires a data buffer, you must specify a buffer length. On many operations, the database engine returns a value to the Data Length. Generally, you should always specify a Data Length before you execute an operation. This control corresponds with the Data Buffer Length parameter.
The Login and Logout dialog boxes allows you to perform the Btrieve login and logout operations for the database engine. Click an area of either image for which you want more information.
Figure 10 Login Dialog
Figure 11 Logout Dialog
Table 60 Function Executor Login and Logout Dialogs
GUI Object
Description
Server
Specifies the server where the database resides that you wish to log in to or log out from. Note that a server name is required to access a database on a Linux or macOS operating system. See also Database URIs in Zen Programmer’s Guide.
Database
Specifies the database on the server to which you want to authenticate.
User Name
The user name you want to authenticate against the database.
Password
The password for the user name.
Client ID
If you want this login or logout to apply to a specific client ID, click Use and specify the range. Otherwise, leave as is.
Sets the state of the file when it is opened. Based on the state, the database engine knows certain conditions that apply to the opened file. For example, a condition could be that the file can be read but not updated (read-only).
Sets the state of the file when it is opened. Based on the state, the database engine knows certain conditions that apply to the opened file. For example, a condition could be that the file can be read but not updated (read-only).
The database engine ignores the Sharing options. The Sharing options apply only to a legacy version of the database engine, Btrieve 6.15.
Create New Btrieve File Dialog
This dialog box allows you to specify additional characteristics for the file being created. Click an area of the image for which you want more information.
Table 63 Function Executor Create File Dialog (Advanced)
GUI Object
Description
Related Information
Key and Segment commands
Allow you to add or delete a key or to add, insert, or delete a key segment.
Displays the keys and segments for the file, listing the starting position, length, attributes, and data type for them. Clicking a row allows you to see, and modify if you want, information in the Key and Segment blocks.
When a file is open, you can show the Transactions toolbar by selecting View > Toolbars > Transactions. This toolbar allows you to manually control transactions. Click an area of the following image to learn about what you can do with this toolbar.
Indicates whether you are currently in a transaction. If you are in a transaction, this display will show either Concurrent or Exclusive.
File Statistics
When a file is open, you can show the File Statistics window by selecting View > File Statistics, clicking the File Statistics icon in the tool bar, or pressing Ctrl+S. It allows you to see the statistics for the file. Click an area of the following image to learn about what you can do in this window.
Table 65 Function Executor File Statistics Dialog
GUI Object
Description
File information
Displays statistical information about the file.
Flags
Allows you to view the flags set for this file. Any flag that is set will have a check mark next to its listing in the dialog box.
Keys
Allows you to view the keys defined in this file.
Key legend
Describes the single letter values that indicate Key attributes for the file.
1 Access Function Executor from the operating system Start menu or Apps screen or from the Tools menu in Zen Control Center.
2 The main window appears.
Figure 12 Function Executor Main Window
Performing Operations Tasks
Because Btrieve provides many operations, this chapter cannot explain them all. The following sections discuss some common operations as well as some new ways of performing them with the Function Executor.
Note Selecting options from all menus performs the intended operation immediately. It does not fill in the grid and wait for you to execute the command as in previous versions. Also, closing the form closes each open file. No longer do you need to manually perform the close operation.
1 When a status code is received using Function Executor, it is displayed on the status bar of the open file.
Move your mouse so it hovers over the status code that is displayed in red.
Figure 13 Status Code Received
2 If you click the status code indicator, the full documentation for the status code is displayed as shown in Figure 14.
Figure 14 Status Code Documentation
Opening a File Tasks
►To open a data file with Function Executor
1 From the File menu, select Open. The following dialog box appears:
Figure 15 Open Btrieve File Dialog Box
.
Note Client ID: If you have Use disabled, Function Executor will use a BTRV() function call. If Use is enabled, it will use a BTRVID() function call for each operation you execute on this file. With Auto enabled, Function Executor will generate a client ID for you. If you have Auto disabled, then you may enter values manually.
2 Click Browse.
3 Double-click the desired file name.
Other Ways to Open a File with Function Executor
•You can drag a file from Windows Explorer into the Open dialog box. This step fills in the file name for you.
•You can drag one or more files into the main window.
•After opening a file to display the editor window, you can use the OpCode 0 to open another file. The file appears in a new window.
•You can run Function Executor from a command prompt and specify a list of file names to open. For example:
WBExec32 person.mkd billing.mkd
You can even use wildcard characters:
WBExec32 *.mkd
Also, in Windows you can associate files with .btr, .dat, .mkd, or any other extension with Function Executor. Then when you double-click the file in Windows Explorer, Function Executor opens it.
Creating a Btrieve File Tasks
There are two options in creating a Btrieve file with Function Executor. If a file is already open, you can clone it. Otherwise, you can start from scratch.
Caution The Btrieve engine uses file names in ways that ignore extensions. Because of this, no two files in the same directory should share a file name and differ only in their file name extension. For example, do not name one data file invoice.btr and another invoice.mkd.
Method 1: Using a current file as a template
1 From the File menu, select New. The following dialog box will appear:
Figure 16 Modify File Definition Dialog Box
2 You can manipulate keys from this dialog box as well. You can Add, Create, or Insert Segments from the Key menu. You can also save the new file as a description for use with BUtil create. Select Save As Desc and indicate the name and location where you would like the file saved.
3 To create the file, click Create. This will open the file and display a message indicating success.
Method 2: Creating a new file from scratch
1 Click the Create icon on the main toolbar; or, if no file is open yet, you may click File and then New, as before.
2 If a file is already open on screen, a selection box will appear. Choose Create New File from Scratch.
3 The same dialog box as before will appear, but it will be blank - allowing you to input brand new values.
4 Start by adding a new Key using the Key menu, or press Ctrl-A.
5 Fill in the attributes for the key in the lower section of the dialog box.
6 Continue adding or removing new keys and segments as desired, using the menus or right-clicking the key in the list.
7 Now click the Create button to execute the B_Create (14) operation. This will automatically open the file on screen as well.
History Tasks
The following tasks are related to the History feature:
