// declare some simple procedures
proc display(cArg)
echo "display=" + cArg
endproc
proc show(cArg)
echo "show=" + cArg
endproc
// create an object based on an anonymous class
myobj = new object()
// add some properties
myobj["name"] = "barry"
myobj["company"] = "recital"
// now declare an anonymous method
myobj["mymethod"] = display
// call the method
myobj.mymethod("hello world") // displays "display=hello world"
// redeclare the method
myobj["mymethod"] = show
// call the method
myobj.mymethod("hello world") // displays "show=hello world"
Where this becomes particularly useful is when you have a procedure that calls anonymous methods in order to process data. This technique can be used to call anonymous procedures in your code.
proc processdata(oArg)
oArg.mymethod(oArg.name)
endproc
proc show(cArg)
echo "show=" + cArg
endproc
myobj = new object()
myobj["name"] = "barry"
myobj["mymethod"] = show
processdata(myobj) // displays "show=barry" In this article Barry Mavin, CEO and Chief Software Architect for Recital provides details on how to use the Recital Universal .NET Data Provider with the Recital Database Server.
Overview
A data provider in the .NET Framework serves as a bridge between an application and a data source. A data provider is used to retrieve data from a data source and to reconcile changes to that data back to the data source.
Each .NET Framework data provider has a DataAdapter object: the .NET Framework Data Provider for OLE DB is the OleDbDataAdapter object, the .NET Framework Data Provider for SQL Server is the SqlDataAdapter object, the .NET Framework Data Provider for ODBC is the OdbcDataAdapter object, and the .NET Framework Data Provider for the Recital Database Server is the RecitalDataAdapter object.
The Recital Universal .NET Data Provider can access any data sources supported by the Recital Database Server. It is not restricted to only access Recital data. It can be used to access server-side ODBC, JDBC and OLE DB data sources also.
Core classes of the Data Provider
The Connection, Command, DataReader, and DataAdapter objects represent the core elements of the .NET Framework data provider model. The Recital Universal .NET Data Provider is plug compatible with the .NET Framework Data Provider for SQL Server. All SQL Server classes are prefixed with "Sql" e.g. SqlDataAdaptor. To use the Recital Universal Data Adaptor, simply change the "Sql" prefix to "Recital" e.g. RecitalDataAdaptor.
The following table describes these objects.
| Object | Description |
|---|---|
| RecitalConnection | Establishes a connection to a specific data source. |
| RecitalCommand | Executes a command against a data source. |
| RecitalDataReader | Reads a forward-only, read-only stream of data from a data source. |
| RecitalDataAdapter | Populates a DataSet and resolves updates with the data source. |
Along with the core classes listed in the preceding table, a .NET Framework data provider also contains the classes listed in the following table.
| Object | Description |
|---|---|
| RecitalTransaction | Enables you to enlist commands in transactions at the data source. |
| RecitalCommandBuilder | A helper object that will automatically generate command properties of a DataAdapter or will derive parameter information from a stored procedure and populate the Parameters collection of a Command object. |
| RecitalParameter | Defines input, output, and return value parameters for commands and stored procedures. |
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 .NET Data Provider supports a connection string format that is similar to the SQL Server connection string format.
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 within the ConnectionString property of the RecitalConnection class.
| Name | Default | Description |
|---|---|---|
| Data Source -or- Server -or- Servername -or- Nodename |
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 -or- Encryption |
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 -or- uid -or- User -or- Username |
The user name used to authenticate access to the remote server. | |
| Connection Pooling -or- Pool |
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.
The gateway can be specified in several formats: |
Populating a DataSet from a DataAdaptor
The ADO.NET DataSet is a memory-resident representation of data that provides a consistent relational programming model independent of the data source. The DataSet represents a complete set of data including tables, constraints, and relationships among the tables. Because the DataSet is independent of the data source, a DataSet can include data local to the application, as well as data from multiple data sources. Interaction with existing data sources is controlled through the DataAdapter.
A DataAdapter is used to retrieve data from a data source and populate tables within a DataSet. The DataAdapter also resolves changes made to the DataSet back to the data source. The DataAdapter uses the Connection object of the .NET Framework data provider to connect to a data source and Command objects to retrieve data from and resolve changes to the data source.
The SelectCommand property of the DataAdapter is a Command object that retrieves data from the data source. The InsertCommand, UpdateCommand, and DeleteCommand properties of the DataAdapter are Command objects that manage updates to the data in the data source according to modifications made to the data in the DataSet.
The Fill method of the DataAdapter is used to populate a DataSet with the results of the SelectCommand of the DataAdapter. Fill takes as its arguments a DataSet to be populated, and a DataTable object, or the name of the DataTable to be filled with the rows returned from the SelectCommand.
The Fill method uses the DataReader object implicitly to return the column names and types used to create the tables in the DataSet, as well as the data to populate the rows of the tables in the DataSet. Tables and columns are only created if they do not already exist; otherwise Fill uses the existing DataSet schema.
Examples in C#:
////////////////////////////////////////////////////////////////////////
// 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 Southwind database
// and 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()
{
RecitalConnection swindConn = new
RecitalConnection("Data Source=localhost;Initial Catalog=southwind");
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;
}
////////////////////////////////////////////////////////////////////////
// The following example uses the RecitalCommand, RecitalDataAdapter and
// RecitalConnection, to select records from a database, and populate a
// DataSet with the selected rows. The filled DataSet is then returned.
// To accomplish this, the method is passed an initialized DataSet, a
// connection string, and a query string that is a SQL SELECT statement
public DataSet SelectRecitalRows(DataSet dataset, string connection, string query)
{
RecitalConnection conn = new RecitalConnection(connection);
SqlDataAdapter adapter = new RecitalDataAdapter();
adapter.SelectCommand = new RecitalCommand(query, conn);
adapter.Fill(dataset);
return dataset;
} After an extended period of intense software development, we are pleased to announce the release of Recital 10 which is a milestone in our development efforts.
The Recital 10 release notes can be found here.
- Recital
A powerful scripting language with an embedded database used for developing desktop database applications on Linux and Unix.
- Recital Server
A cross-platform SQL database and application server.
- Recital Web
A server-side scripting language with an embedded SQL database for creating web 2.0 web applications.
We are pleased to announce the release of Recital 10.0.3.
Here is a brief list of features and functionality that you will find in the 10.0.3 release.
- New Commands:
- SET TMPNAMPATH ON|OFF
- REMOVE TABLE - New Functions:
- CURSORGETPROP()
- CURSORSETPROP()
- CURVAL()
- GETFLDSTATE()
- OLDVAL()
- TABLEREVERT()
- TABLEUPDATE()
- SETFLDSTATE() - Enhanced Functions:
- TMPNAM() - additional parameter to specify the return of basename only
- MAILATTACH() - parameter changed from array to filename to allow directory and file extension to be specified - Enhancements:
- DO level increased from 32 to 64. - Fixes:
- Delay exiting Recital after SYS(3) or SYS(2015)
- SET SOFTSEEK issue when search key above first record in index
- Compilation error with REPLACE command after UDF call
- FETCH INTO memvars error
- END TRANSACTION at command prompt error
- ROLLBACK locking error
- Linux ODBC Driver undefined symbol error
- RELEASE variable with same name as variable in calling program issue
- SQLCODE() issue on non-gateway data access
- Issuing two SQLEXEC() calls error
- LASTSEQNO() in workareas > 1 error
- SET RELATION to detail table in workarea 1 issue
- LIST STATUS on empty table delay
- SET AUTOCATALOG alias entries error
- ADD OBJECT in DEFINE CLASS error
- DEACTIVATE WINDOW error
- SORT error
- Other reported bugs
Here's how to set up field validation based on dynamic values from another table.
Using the products.dbf table from the southwind sample database, validation can be added to the categoryid field to ensure it matches an existing categoryid from the categories.dbf table.
open database southwindThe rlookup() function checks whether an expression exists in the index (master or specified) of the specified table . An attempt to update categoryid with a value not in the list will give an error: Validation on field 'CATEGORYID' failed.
alter table products add constraint;
(categoryid set check rlookup(products.categoryid,categories))
If you have access to the Recital Workbench, you can use the modify structure worksurface to add and alter your dictionary entries, including a customized error message if required.
Here's how to set up field validation for a field with a small static number of acceptable values.
Using the example.dbf table from the southwind sample database, validation can be added to the title field to ensure it matches one of a list values.
open database southwindThe inlist() function checks whether the specified expression exists in the comma-separated list which follows. An attempt to update title with a value not in the list will give an error: Validation on field 'TITLE' failed.
alter table example add constraint;
(title set check inlist(alltrim(title),"Miss","Mr","Mrs","Ms"))
If you have access to the Recital Workbench, you can use the modify structure worksurface to add and alter your dictionary entries, including a customized error message if required.
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.
In this article Chris Mavin, explains and details how to use the Recital Database Server with the Open Source Servlet Container Apache Tomcat.
Overview
PHP has exploded on the Internet, but its not the only way to create web applications and dynamic websites. Using Java Servlets, JavaServer Pages and Apache Tomcat you can develop web applications in a more powerful full featured Object Oriented Language, that is easier to debug, maintain, and improve.
Tomcat Installation
There are a number of popular Java application servers such as IBM Web Sphere and BEA WebLogic but today we will be talking about the use of Apache Tomcat 5, the Open Source implementation of the Java Servlet and JavaServer Pages technologies developed at the Apache Software Foundation. The Tomcat Servlet engine is the official reference implementation for both the Servlet and JSP specifications, which are developed by Sun under the Java Community Process. What this means is that the Tomcat Server implements the Servlet and JSP specifications as well or better than most commercial application servers.
Apache Tomcat is available for free but offers many of the same features that commercially available Web application containers boast.
Tomcat 5 supports the latest Servlet and JSP specifications, Servlet 2.4, and JSP 2.0, along with features such as:
-
Tomcat can run as a standalone webserver or a Servlet/JSP engine for other Web Servers.
-
Multiple connectors - for enabling multiple protocol handlers to access the same Servlet engine.
-
JNDI - The Java Naming and Domain Interface is supported.
-
Realms - Databases of usernames and passwords that identify valid users of a web application.
-
Virtual hosts - a single server can host applications for multiple domain names. You need to edit server.xml to configure virtual hosts.
-
Valve chains.
-
JDBC - Tomcat can be configured to use any JDBC driver.
-
DBCP - Tomcat can use the Apache commons DBCP for connection pooling.
-
Servlet reloading (Tomcat monitors any changes to the classes deployed within that web server.)
-
HTTP functionality - Tomcat functions as a fully featured Web Server.
-
JMX, JSP and Struts-based administration.
Tomcat Installation
In this next two sections we will walk through the install and setup of Tomcat for use with the Recital database server.
To download Tomcat visit the Apache Tomcat web site is at http://jakarta.apache.org/tomcat.
Follow the download links to the binary for the hardware and operating system you require.
For Tomcat to function fully you need a full Java Development Kit (JDK). If you intend to simply run pre compiled JavaServer pages you can do so using just the Java Runtime Environment(JRE).
The JDK 1.5 is the preferred Java install to work with Tomcat 5, although it is possible to run Tomcat 5 with JDK 1.4 but you will have to download and install the compat archive available from the Tomcat website.
For the purpose of this article we will be downloading and using Tomcat 5 for Linux and JDK 5.0,
you can download the JDK at http://java.sun.com/javase/downloads/index.jsp.
Now we have the JDK, if the JAVA_HOME environment variable isn't set we need to set it to refer to the base JDK install directory.
Linux/Unix:
$ JAVA_HOME= /usr/lib/j2se/1.4/ $ EXPORT $JAVA_HOME
Windows NT/2000/XP:
Follow the following steps:
1. Open Control Panel.
2. Click the System icon.
3. Go to the Advanced tab.
4. Click the Environment Variables button.
5. Add the JAVA_HOME variable into the system environment variables.
The directory structure of a Tomcat installation comprises of the following:
/bin - Contains startup, shutdown and other scripts. /common - Common classes that the container and web applications can use. /conf - Contains Tomcat XML configuration files XML files. /logs - Serlvet container and application logs. /server - Classes used only by the Container. /shared - Classes shared by all web application. /webapps - Directory containing the web applications. /work - Temporary directory for files and directories.
The important files that you should know about are the following:
-
server.xml
The Tomcat Server main configuration file is the [tomcat install path]\conf\server.xml file. This file is mostly setup correctly for general use. It is within this file where you specify the port you wish to be running the server on. Later in this article I show you how to change the default port used from 8080 to port 80.
-
web.xml
The web.xml file provides the configuration for your web applications. There are two locations where the web.xml file is used,
web-inf\web.xml provides individual web application configurations and [tomcat install path]conf\web.xml contains the server wide configuration.
Setting up Tomcat for use
We'll start by changing the port that Tomcat will be listening on to 80.
To do this we need to edit [tomcat install path]/conf/server.xml and change the port attribute of the connector element from 8080 to 80.
After you have made the alteration the entry should read as:
<!-- Define a non-SSL HTTP/1.1 Connector on port 8080 --> <Connector port="80" maxHttpHeaderSize="8192"
Next we want to turn on Servlet reloading, this will cause the web application to be recompiled each time it is accessed, allowing us to make changes to the files without having to worry about if the page is being recompiled or not.
To enable this you need to edit [tomcat install path]/conf/context.xml and change <Context> element to <Context reloadable="true">.
After you have made the alteration the entry should read as:
<Context reloadable="true"> <WatchedResource>WEB-INF/web.xml</WatchedResource> </Context>
Next we want to enable the invoker Servlet.
The "invoker" Servlet executes anonymous Servlet classes that have not been defined in a web.xml file. Traditionally, this Servlet is mapped to the URL pattern "/servlet/*", but you can map it to other patterns as well. The extra path info portion of such a request must be the fully qualified class name of a Java class that implements Servlet, or the Servlet name of an existing Servlet definition.
To enable the invoker Servlet you need to edit the to [tomcat install path]/conf/web.xml and uncomment the Servlet and Servlet-mapping elements that map the invoker /servlet/*.
After you have made the alteration the entry should read as:
<servlet> <servlet-name>invoker</servlet-name> <servlet-class>org.apache.catalina.servlets.InvokerServlet</servlet-class> <init-param> <param-name>debug</param-name> <param-value>0</param-value> </init-param> <load-on-startup>2</load-on-startup> </servlet> <servlet-mapping> <servlet-name>invoker</servlet-name> <url-pattern>/servlet/*</url-pattern> </servlet-mapping>
If you are you not interested in setting up your own install of Tomcat there are prebuilt versions Tomcat that has all of the above changes already made, and has the test HTML, JSP, and Servlet files already bundled. Just unzip the file, set your JAVA_HOME
Next we will give Tomcat and your web applications access to the Recital JDBC driver.
For the purposes of this article we are going to install the Recital JDBC driver in the /[tomcat install path]/common/lib/ this gives Tomcat and your web applications access to the Recital JDBC driver. The driver can be installed in a number of places in the Tomcat tree, giving access to the driver to specific application or just to the web application and not the container. For more information refer to the Tomcat documentation.
Copy the recitalJDBC.jar which is located at /[recital install path]/drivers/recitalJDBC.jar to the /[tomcat install path]/common/lib/ directory.
Linux:
$cp /[recital install path]/drivers/recitalJDBC.jar /[tomcat install path]/common/lib/
Once you have completed all the steps detailed above, fire up the server using the script used by your platform's Tomcat installation.
Linux/Unix:
[tomcat install path]/bin/startup.sh
Windows:
[tomcat install path]/bin/startup
If you are having problems configuring your Tomcat Installation or would like more detail visit the online documentation a the Apache Tomcat site.
Example and Links
Now we have setup our Tomcat installation, lets get down to it with a JSP example which uses the Recital JDBC driver to access the demonstration database (southwind) shipped with the Recital Database Server.
The example provided below is a basic JDBC web application, where the user simply selects a supplier from the listbox and requests the products supplied by that supplier.
To run the example download and extract the tar archive or simple save each of the two jsp pages individually into /[tomcat install path]/webapps/ROOT/ on your server.
By enabling the invoker Servlet earlier we have removed the need to set the example up as a web application in the Tomcat configuration files.
You can now access the example web application at http://[Server Name]/supplier.jsp if the page doesn't display, check you have followed all the Tomcat installation steps detailed earlier in this article and then make sure both Tomcat and a licensed Recital UAS are running.
Downloads:
Archive: jspExample.tar
Right click and save as individual files and rename as .jsp files:
supplier.txt details.txt
Further Reading on JSP and JDBC can be found at http://www-128.ibm.com/developerworks/java/library/j-webdata/
Final Thoughts
Recital and Apache tomcat are a powerful combination, using Java Servlet technology you can separate application logic and the presentation extremely well. Tomcat, JSP, Java Servlets and the Recital database server form a robust platform independent, easily maintained and administered solution with which to unlock the power of your Recital, Foxpro, Foxbase, Clipper, RMS and C-SAM data.
The getUIComponentBitmapData method can create bitmapdata for a given IUIComponent. Pass any UIcomponent to get its respective bitmapdata.
public static function getUIComponentBitmapData(target:IUIComponent):BitmapData {
var resultBitmapData:BitmapData = new BitmapData(target.width, target.height);
var m:Matrix = new Matrix();
resultBitmapData.draw(target, m);
return resultBitmapData;
}
Now convert the bitmapdata to a jpeg bytearray.
private static function encodeToJPEG(data:BitmapData, quality:Number = 75):ByteArray {
var encoder:JPGEncoder = new JPGEncoder(quality);
return encoder.encode(data);
}
Now encode the ByteArray into Base64.
public static function base64Encode(data:ByteArray):String {
var encoder:Base64Encoder = new Base64Encoder();
encoder.encodeBytes(data);
return encoder.flush();
}
Upload the base64 encoded ByteArray to the server.
public static uploadData():void {
var url:String = "saveFile.php";
var urlRequest:URLRequest = new URLRequest(url);
urlRequest.method = URLRequestMethod.POST;
var urlLoader:URLLoader = new URLLoader();
var urlVariables:URLVariables = new URLVariables();
urlVariables.file = jpgEncodedFile; // as returned from base64Encode()
urlLoader.data = urlVariables;
urlLoader.load(urlRequest);
}
The saveFile.php file on the server.
- New MD5( expC ) function to calculate an MD5 crypto key from any character expression
- New MD5FILE( expC ) function calculates an MD5 crypto key for a given filename. If the filename is a pattern e.g *.* it will calculate the key across all files matching the pattern
- New mod_recital.so available for using Recital Web on linux x86_32
- New mod_recital64.so available for using Recital Web on linux x86_64