If you have a live linux site that is running vmware virtual machines, you can pause the virtual machines when you want to perform a backup, I use acronis for linux which does incremental backups and you can specify a command to run before and after the backup, this allows backups to be performed at scheduled times daily without any intervention. In my examples below, the virtual machine i want to control is in /root/vmware/Recital/Recital.vmx
To pause the virtual machine on linux:
# vmrun pause /root/vmware/Recital/Recital.vmx
and then to unpause after the backup has completed:
# vmrun unpause /root/vmware/Recital/Recital.vmx
That is basicallty it, no need to attend the backup and it can be perfomed at a suitable time so no users are affected.
Incidentally, vmrun lets you startup a virtual machine at system startup too, without needing the GUI:
# vmrun start /root/vmware/Recital/Recital.vmx
Or alternatively stop it:
# vmrun stop /root/vmware/Recital/Recital.vmx
There are lots of other capabilities of this command, running applications inside the virtual machine etc etc. For full details just type vmrun in a terminal window.
One of the attractive features of Linux is the impressive 3D desktop that even works on most older hardware.
You can enabled the 3D Desktop on CentOS5 by installing the compiz package:
yum install compiz
After you have done this, go to the top panel and click System, then select Preferences > and click 'Desktop Effects.
You will get a new dialog. To test and see if your hardware supports the 3D Desktop, press the button Enable Desktop Effects. If everything works fine, you can select Keep Settings.
Then test your 3D Desktop by pressing Ctrl-Alt-Left and Ctrl-Alt-Right, or drag a window around or even out of the screen to the left or right. If you maximize a window, you will see another cool effect. If you move the mouse to the upper-right corner of the screen you see all your opened applications.Way cool!
Recital provides a wide variety of connectivity solutions to external data sources. This article provides an overview.
In this article Barry Mavin, CEO and Chief Software Architect for Recital details how to Build C Extension Libraries to use with Recital.
Overview
It is possible to extend the functionaliy of Recital products using "Extension libraries" that can be written in C. These extension libraries, written using the Recital/SDK API, are dynamically loadable from all Recital 9 products. This includes:
- Recital
- Recital Server
- Recital Web
Building C Extension Libraries
You can create C wrappers for virtually any native operating system function and access these from the Recital 4GL. Unlike traditional APIs which only handle the development of C functions that are callable from the 4GL, the Recital/SDK allows you to build Classes that are accessible from all Recital products. e.g. You could create a GUI framework for Linux that handles VFP system classes!
To deploy your C Extension Libraries, copy them to the following location:
Windows:
\Program Files\Recital\extensions
Linux/Unix:
/opt/recital/extensions
Please see the Recital/SDK API Reference documentation for further details.
Sample code
Listed below is the complete example of a C Extension Library.:
////////////////////////////////////////////////////////////////////////////////
#include "mirage_demo.h"
////////////////////////////////////////////////////////////////////////////////
// Declare your functions and classes below as follows:
//
// Recital Function Name, C Function Name, Type (Function or Class)
//
#define MAX_ELEMENTS 7
static struct API_SHARED_FUNCTION_TABLE api_function_table[MAX_ELEMENTS] = {
{"schar", "fnSamplesCharacter", API_FUNCTION},
{"stype", "fnSamplesType", API_FUNCTION},
{"slog", "fnSamplesLogical", API_FUNCTION},
{"snum", "fnSamplesNumeric", API_FUNCTION},
{"sopen", "fnSamplesOpen", API_FUNCTION},
{"myclass", "clsMyClass", API_CLASS},
{NULL, NULL, -1}
};
////////////////////////////////////////////////////////////////////////////////
// Recital API initialization. This should be in only ONE of your C files
// **IT SHOULD NEVER BE EDITED OR REMOVED**
INIT_API;
///////////////////////////////////////////////////////////////////////
// This is an example of passing a character parameter and returning one.
RECITAL_FUNCTION fnSamplesCharacter(void)
{
char *arg1;
if (!_parse_parameters(PCOUNT, "C", &arg1)) {
ERROR(-1, "Incorrect parameters");
}
_retc(arg1);
}
///////////////////////////////////////////////////////////////////////
// This is an example of passing a numeric parameter and returning one.
RECITAL_FUNCTION fnSamplesNumeric(void)
{
int arg1;
if (!_parse_parameters(PCOUNT, "N", &arg1)) {
ERROR(-1, "Incorrect parameters");
}
_retni(arg1);
}
///////////////////////////////////////////////////////////////////////
// This is an example returns the data type of the parameter passed.
RECITAL_FUNCTION fnSamplesType(void)
{
char result[10];
if (PCOUNT != 1) {
ERROR(-1, "Incorrect parameters");
}
switch (_parinfo(1)) {
case API_CTYPE:
strcpy(result, "Character");
break;
case API_NTYPE:
strcpy(result, "Numeric");
break;
case API_LTYPE:
strcpy(result, "Logical");
break;
case API_DTYPE:
strcpy(result, "Date");
break;
case API_TTYPE:
strcpy(result, "DateTime");
break;
case API_YTYPE:
strcpy(result, "Currency");
break;
case API_ATYPE:
strcpy(result, "Array");
break;
default:
strcpy(result, "Unkown");
break;
}
_retc(result);
}
///////////////////////////////////////////////////////////////////////
// This is an example returns "True" or False.
RECITAL_FUNCTION fnSamplesLogical(void)
{
char result[10];
int arg1;
if (!_parse_parameters(PCOUNT, "L", &arg1)) {
ERROR(-1, "Incorrect parameters");
}
if (arg1) strcpy(result, "True");
else strcpy(result, "False");
_retc(result);
}
///////////////////////////////////////////////////////////////////////
// This example opens a table.
RECITAL_FUNCTION fnSamplesOpen(void)
{
char *arg1;
if (!_parse_parameters(PCOUNT, "C", &arg1)) {
ERROR(-1, "Incorrect parameters");
}
if (_parinfo(1) == API_CTYPE) {
_retni(COMMAND(arg1));
} else {
_retni(-1);
}
}
///////////////////////////////////////////////////////////////////////
// Define the MyClass CLASS using the API macros
///////////////////////////////////////////////////////////////////////
RECITAL_EXPORT int DEFINE_CLASS(clsMyClass)
{
/*-------------------------------------*/
/* Dispatch factory methods and return */
/*-------------------------------------*/
DISPATCH_FACTORY();
/*---------------------------------*/
/* Dispatch constructor and return */
/*---------------------------------*/
DISPATCH_METHOD(clsMyClass, Constructor);
/*--------------------------------*/
/* Dispatch destructor and return */
/*--------------------------------*/
DISPATCH_METHOD(clsMyClass, Destructor);
/*-----------------------------------*/
/* Dispatch DEFINE method and return */
/*-----------------------------------*/
DISPATCH_METHOD(clsMyClass, Define);
/*------------------------------*/
/* Dispatch SET or GET PROPERTY */
/* method for property NumValue */
/* then return. */
/*------------------------------*/
DISPATCH_PROPSET(clsMyClass, NumValue);
DISPATCH_PROPGET(clsMyClass, NumValue);
/*------------------------------*/
/* Dispatch SET or GET PROPERTY */
/* method for property LogValue */
/* then return. */
/*------------------------------*/
DISPATCH_PROPSET(clsMyClass, LogValue);
DISPATCH_PROPGET(clsMyClass, LogValue);
/*-------------------------------*/
/* Dispatch SET or GET PROPERTY */
/* method for property DateValue */
/* then return. */
/*-------------------------------*/
DISPATCH_PROPSET(clsMyClass, DateValue);
DISPATCH_PROPGET(clsMyClass, DateValue);
/*-------------------------------*/
/* Dispatch SET or GET PROPERTY */
/* method for property TimeValue */
/* then return. */
/*-------------------------------*/
DISPATCH_PROPSET(clsMyClass, TimeValue);
DISPATCH_PROPGET(clsMyClass, TimeValue);
/*-------------------------------*/
/* Dispatch SET or GET PROPERTY */
/* method for property CurrValue */
/* then return. */
/*-------------------------------*/
DISPATCH_PROPSET(clsMyClass, CurrValue);
DISPATCH_PROPGET(clsMyClass, CurrValue);
/*-------------------------------*/
/* Dispatch SET or GET PROPERTY */
/* method for property CharValue */
/* then return. */
/*-------------------------------*/
DISPATCH_PROPSET(clsMyClass, CharValue);
DISPATCH_PROPGET(clsMyClass, CharValue);
/*------------------------------*/
/* Dispatch SET or GET PROPERTY */
/* method for property ObjValue */
/* then return. */
/*------------------------------*/
DISPATCH_PROPSET(clsMyClass, ObjValue);
DISPATCH_PROPGET(clsMyClass, ObjValue);
/*-----------------------------------*/
/* If message not found return error */
/*-----------------------------------*/
OBJECT_RETERROR("Unknown message type");
}
////////////////////////////////////////////////////////////////////////////////
// Define METHOD handlers
////////////////////////////////////////////////////////////////////////////////
DEFINE_METHOD(clsMyClass, Constructor)
{
struct example_data *objectDataArea;
/* Allocate memory for objects objectData area */
objectDataArea = (struct example_data *)
malloc(sizeof(struct example_data));
if (objectDataArea == NULL) return(-1);
/* Assign the default property values */
strcpy(objectDataArea->prop_charvalue, "Test API object");
objectDataArea->prop_numvalue = 15.2827;
objectDataArea->prop_logvalue = 'F';
strcpy(objectDataArea->prop_datevalue, DATE_DATE());
strcpy(objectDataArea->prop_timevalue, DATE_DATETIME());
strcpy(objectDataArea->prop_currvalue, "15.2827");
strcpy(objectDataArea->object_name, "APIobject");
objectDataArea->prop_objvalue
= OBJECT_NEW(objectDataArea->object_name, "exception", NULL);
/* Set the object objectData area */
OBJECT_SETDATA((char *)objectDataArea);
return(0);
}
DEFINE_METHOD(clsMyClass, Destructor)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData != NULL) {
if (objectData->prop_objvalue != NULL)
OBJECT_DELETE(objectData->prop_objvalue);
free(objectData);
objectData = NULL;
}
return(0);
}
DEFINE_METHOD(clsMyClass, Define)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
struct API_EXPRESSION result;
char buffer[512];
int rc;
/* Check the object class */
OBJECT_GETPROPERTY(objectData->prop_objvalue, "class", buffer);
rc = OBJECT_GETARG(buffer, &result);
if (result.errno == 0 && result.type == 'C'
&& strcmp(result.character, "Exception") == 0) {
switch (OBJECT_GETARGC()) {
case 1:
rc = OBJECT_GETPARAMETER(1, &result);
if (result.errno == 0 && result.type == 'C') {
OBJECT_SETARG(buffer, &result);
rc = OBJECT_SETPROPERTY(objectData->prop_objvalue,
"message", buffer);
}
break;
case 2:
rc = OBJECT_GETPARAMETER(2, &result);
if (result.errno == 0 && result.type == 'N') {
OBJECT_SETARG(buffer, &result);
rc = OBJECT_SETPROPERTY(objectData->prop_objvalue,
"errorno", buffer);
}
}
}
result.type = 'L';
result.logical = (rc == 0 ? 'T' : 'F');
OBJECT_RETRESULT(&result);
}
////////////////////////////////////////////////////////////////////////////////
// Define GET property handlers
////////////////////////////////////////////////////////////////////////////////
DEFINE_PROPERTYGET(clsMyClass, NumValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData == NULL) return(-1);
OBJECT_RETPROPERTY('N', objectData->prop_numvalue);
}
DEFINE_PROPERTYGET(clsMyClass, LogValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData == NULL) return(-1);
OBJECT_RETPROPERTY('L', objectData->prop_logvalue);
}
DEFINE_PROPERTYGET(clsMyClass, DateValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData == NULL) return(-1);
OBJECT_RETPROPERTY('D', objectData->prop_datevalue);
}
DEFINE_PROPERTYGET(clsMyClass, TimeValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData == NULL) return(-1);
OBJECT_RETPROPERTY('T', objectData->prop_timevalue);
}
DEFINE_PROPERTYGET(clsMyClass, CurrValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData == NULL) return(-1);
OBJECT_RETPROPERTY('Y', objectData->prop_currvalue);
}
DEFINE_PROPERTYGET(clsMyClass, CharValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData == NULL) return(-1);
OBJECT_RETPROPERTY('C', objectData->prop_charvalue);
}
DEFINE_PROPERTYGET(clsMyClass, ObjValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
if (objectData == NULL) return(-1);
OBJECT_RETPROPERTY('O', objectData->prop_objvalue);
}
////////////////////////////////////////////////////////////////////////////////
// Define SET property handlers
////////////////////////////////////////////////////////////////////////////////
DEFINE_PROPERTYSET(clsMyClass, NumValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
struct API_EXPRESSION result;
int rc = OBJECT_ERROR;
OBJECT_GETVALUE(&result);
if (result.errno == 0 && result.type == 'N') {
objectData->prop_numvalue = result.number;
rc = OBJECT_SUCCESS;
}
return(rc);
}
DEFINE_PROPERTYSET(clsMyClass, LogValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
struct API_EXPRESSION result;
int rc = OBJECT_ERROR;
OBJECT_GETVALUE(&result);
if (result.errno == 0 && result.type == 'L') {
objectData->prop_logvalue = result.logical;
rc = OBJECT_SUCCESS;
}
return(rc);
}
DEFINE_PROPERTYSET(clsMyClass, DateValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
struct API_EXPRESSION result;
int rc = OBJECT_ERROR;
OBJECT_GETVALUE(&result);
if (result.errno == 0 && result.type == 'D') {
strcpy(objectData->prop_datevalue, DATE_DTOS(result.date));
rc = OBJECT_SUCCESS;
}
return(rc);
}
DEFINE_PROPERTYSET(clsMyClass, TimeValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
struct API_EXPRESSION result;
int rc = OBJECT_ERROR;
OBJECT_GETVALUE(&result);
if (result.errno == 0 && result.type == 'T') {
strcpy(objectData->prop_timevalue, DATE_TTOS(result.datetime));
rc = OBJECT_SUCCESS;
}
return(rc);
}
DEFINE_PROPERTYSET(clsMyClass, CurrValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
struct API_EXPRESSION result;
int rc = OBJECT_ERROR;
OBJECT_GETVALUE(&result);
if (result.errno == 0 && result.type == 'Y') {
strcpy(objectData->prop_currvalue, CURR_YTOS(result.currency));
rc = OBJECT_SUCCESS;
}
return(rc);
}
DEFINE_PROPERTYSET(clsMyClass, CharValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
struct API_EXPRESSION result;
int rc = OBJECT_ERROR;
OBJECT_GETVALUE(&result);
if (result.errno == 0 && result.type == 'C') {
strcpy(objectData->prop_currvalue, result.character);
rc = OBJECT_SUCCESS;
}
return(rc);
}
DEFINE_PROPERTYSET(clsMyClass, ObjValue)
{
struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
OBJECT objvalue;
int rc = OBJECT_ERROR;
if (OBJECT_GETTYPE() == 'O') {
objvalue = OBJECT_GETOBJECT();
objectData->prop_objvalue = OBJECT_ASSIGN(objvalue, objectData->object_name);
rc = OBJECT_SUCCESS;
}
return(rc);
}
FOREACH array_expression AS value
statements...
ENDFOR
FOREACH array_expression AS key => value
statements...
ENDFOR
The first form loops over the array given by array_expression. On each loop, the value of the current element is assigned to value and the internal array pointer is advanced by one (so on the next loop, you'll be looking at the next element). The second form does the same thing, except that the current element's key will be assigned to the variable key on each loop. This form works only on associative arrays and objects.
APPEND FROM TYPE CSV <file-name.csv>The TYPE keyword has now been enhanced to support a comma separated values (CSV) format
In this article Barry Mavin, CEO and Chief Software Architect for Recital, details how to use the Client Drivers provided with the Recital Database Server to work with local or remote server-side OLE DB data sources.
Overview
The Recital Universal .NET Data Provider provides connectivity to the Recital Database Server running on any supported platform (Windows, Linux, Unix, OpenVMS) using the RecitalConnection object.
The Recital Universal JDBC Driver provides the same functionality for java applications.
The Recital Universal ODBC Driver provides the same functionality for applications that use ODBC.
Each of the above Client Drivers use a connection string to describe connections parameters.
The basic format of a connection string consists of a series of keyword/value pairs separated by semicolons. The equal sign (=) connects each keyword and its value.
The following table lists the valid names for keyword/values.
| Name | Default | Description |
|---|---|---|
|
Data Source
|
The name or network address of the instance of the Recital Database Server which to connect to. | |
| Directory | The target directory on the remote server where data to be accessed resides. This is ignored when a Database is specified. | |
|
Encrypt |
false | When true, DES3 encryption is used for all data sent between the client and server. |
| Initial Catalog -or- Database |
The name of the database on the remote server. | |
| Password -or- Pwd |
The password used to authenticate access to the remote server. | |
| User ID | The user name used to authenticate access to the remote server. | |
|
Connection Pooling |
false | Enable connection pooling to the server. This provides for one connection to be shared. |
| Logging | false | Provides for the ability to log all server requests for debugging purposes |
| Rowid | true | When Rowid is true (the default) a column will be post-fixed to each SELECT query that is a unique row identifier. This is used to provide optimised UPDATE and DELETE operations. If you use the RecitalSqlGrid, RecitalSqlForm, or RecitalSqlGridForm components then this column is not visible but is used to handle updates to the underlying data source. |
| Logfile | The name of the logfile for logging | |
| Gateway |
Opens an SQL gateway(Connection) to a foreign SQL data source on the remote server. Using Gateways, you can transparently access the following local or remote data sources:
The gateway can be specified in several formats: servertype@nodename:username/password-database e.g. oracle@nodename:username/password-database mysql@nodename:username/password-database postgresql@nodename:username/password-database -or- odbc:odbc_data_source_name_on_server oledb:oledb_connection_string_on_server jdbc:jdbc_driver_path_on_server;jdbc:Recital:args |
To connect to a server-side OLE DB data source, you use the gateway=value key/value pair in the following way.
gateway=oledb:oledb_connection_string_on_server
ImportantWhen specifying the connection string be sure to quote the gateway= with "...".
You can find examples of connection strings for most ODBC and OLE DB data sources by clicking here.
Example in C# using the Recital Universal .NET Data Provider:
////////////////////////////////////////////////////////////////////////
// include the references below
using System.Data;
using Recital.Data;
////////////////////////////////////////////////////////////////////////
// The following code example creates an instance of a DataAdapter that
// uses a Connection to the Recital Database Server, and a gateway to
// the SQL server Northwind database. It then populates a DataTable
// in a DataSet with the list of customers. The SQL statement and
// Connection arguments passed to the DataAdapter constructor are used
// to create the SelectCommand property of the DataAdapter.
public DataSet SelectCustomers()
{
string gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
Data Source=localhost;Integrated Security=SSPI";
RecitalConnection swindConn = new
RecitalConnection("Data Source=localhost;gateway=\""+gateway+"\");
RecitalCommand selectCMD = new
RecitalCommand("SELECT CustomerID, CompanyName FROM Customers", swindConn);
selectCMD.CommandTimeout = 30;
RecitalDataAdapter custDA = new RecitalDataAdapter();
custDA.SelectCommand = selectCMD;
swindConn.Open();
DataSet custDS = new DataSet();
custDA.Fill(custDS, "Customers");
swindConn.Close();
return custDS;
}
Example in Java using the Recital Universal JDBC Driver:
////////////////////////////////////////////////////////////////////////
// standard imports required by the JDBC driver
import java.sql.*;
import java.io.*;
import java.net.URL;
import java.math.BigDecimal;
import Recital.sql.*;
////////////////////////////////////////////////////////////////////////
// The following code example creates a Connection to the Recital
// Database Server, and a gateway to the SQL server Northwind database.
// It then retrieves all the customers.
public void SelectCustomers()
{
// setup the Connection URL for JDBC
String gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
Data Source=localhost;Integrated Security=SSPI";
String url = "jdbc:Recital:Data Source=localhost;gateway=\""+gateway+"\";
// load the Recital Universal JDBC Driver
new RecitalDriver();
// create the connection
Connection con = DriverManager.getConnection(url);
// create the statement
Statement stmt = con.createStatement();
// perform the SQL query
ResultSet rs = stmt.executeQuery("SELECT CustomerID, CompanyName FROM Customers");
// fetch the data
while (rs.next())
{
String CompanyID = rs.getString("CustomerID");
String CompanyName = rs.getString("CompanyName");
// do something with the data...
}
// Release the statement
stmt.close();
// Disconnect from the server
con.close();
}
Key features of the Recital scripting language include:
What are the key feature of the Recital database?
- High performance database application scripting language
- Modern object-oriented language features
- Easy to learn, easy to use
- Fast, just-in-time compiled
- Develop desktop or web applications
- Cross-platform support
- Extensive built-in functions
- Superb built-in SQL command integration
- Navigational data access for the most demanding applications
In this article Barry Mavin, CEO and Chief Software Architect for Recital, details how to work with Triggers in the Recital Database Server.
Overview
A trigger is a special kind of stored procedure that runs when you modify data in a specified table using one or more of the data modification operations: UPDATE, INSERT, or DELETE.
Triggers can query other tables and can include complex SQL statements. They are primarily useful for enforcing complex business rules or requirements. For example, you can control whether to allow a new order to be inserted based on a customer's current account status.
Triggers are also useful for enforcing referential and data integrity.
Triggers can be used with any data source that is handled natively by the Recital Database Engine. This includes Recital, FoxPro, FoxBASE, Clipper, dBase, CISAM, and RMS data,
Creating and Editing Triggers
To create a new Trigger, right-click the Procedures node in the Databases tree of the Project Explorer and choose Create. To modify an existing Trigger select the Trigger in the Databases Tree in the Project Explorer by double-clicking on it, or select Modify from the context menu. By convertion we recommend that you name your Stored Procedures beginning with "sp_xxx_", user-defined functions with "f_xxx_", and Triggers with "dt_xxx_", where xxx is the name of the table that they are associated with.
Associating Triggers with a Table
Once you have written your Triggers as detailed above you can associate them with the operations performed on a Table by selecting the Table tab.
The Tables tab allows you to select a Trigger procedure by clicking on the small button at the right of the Text field.
Types of Triggers
As can be seen from the Tables tab detailed below, The Recital Database Server handles 6 distinct types of Triggers.
Open Trigger
The Open Trigger is called after is a table is opened but before any operations are performed on it. You can use this trigger to record a log of table usage or provide a programmable means of checing security. If the Trigger procedure returns .F. (false), then the table is not opened. You can use a TRY...CATCH block around the associated command to inform the user.
Close Trigger
The Close Trigger is called just prior to a table being closed. In this trigger you may find it useful to get transaction counts by using the IOSTATS() built-in 4GL function, and record these values in a transaction log.
Update Trigger
The Update Trigger is called prior to a record update operation being performed. You can use this trigger to perform complex application or data specific validation. If the Trigger procedure returns .F. (false), then the record is not updated. You can use inform the user from within the Trigger procedure the reason that the data cannot be updated.
Delete Trigger
The Delete Trigger is called prior to a record delete operation being performed. You can use this trigger to perform complex application or data specific validation such as cross-table lookups e.g. attempting to delete a customer recortd when there are still open orders for that specific customer. If the Trigger procedure returns .F. (false), then the record is not deleted.
Insert Trigger
The Insert Trigger is called prior to a record insert (append) operation being performed. You can use this trigger to perform such tasks as setting up default values of columns within the record. If the Trigger procedure returns .F. (false), then the record is not inserted.
Rollback Trigger
The RollbackTrigger is called prior to a rollback operation being performed from within a form. If the Trigger procedure returns .F. (false), then the record is not rolled back to its original state.
Testing the Trigger
To test run the Trigger, select the Trigger in the Databases Tree in the Project Explorer by double-clicking on it. Once the Database Administrator is displayed, click the Run button to run the Trigger.