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We are pleased to announce the immediate availability of Recital 10.0.1.

Included in this version are:

  • Improved SQL query optimizer
  • *New* apache plugin for building Recital web apps on x86_64 (mod_recital64.so)
  • Performance improvements in connections to Recital Server and Recital Web.
  • Recital ODBC driver performance improvements and bug fixes
  • Miscellaneous bug fixes 
The download is available from http://www.recitalsoftware.com in the downloads section of our website.

Existing Recital 10 users can download the patch file and apply it to an existing installation.

Enjoy!
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In this article Barry Mavin, CEO and Chief Software Architect for Recital, details on how to use the Client Drivers provided with the Recital Database Server to work with local or remote server-side JDBC 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 equals sign (=) connects each keyword and its value.

The following table lists the valid names for keyword/values.


Name Default Description

Data Source
-or-
Server
-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   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.
Using Gateways, you can transparently access the following local or remote data sources:

  • Recital
  • Oracle
  • ODBC (Server-side ODBC data sources)
  • JDBC (Server-side JDBC data sources)
  • ADO (Use this to connect to SQL Server and other Native Windows OLEDB data sources)
  • MySQL
  • PostgreSQL
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 JDBC data source, you ue the gateway=value key/value pair in the following way.

gateway=jdbc:jdbc_driver_path_on_server;jdbc:Recital:args

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
// Recital Southwind database. It then populates a DataTable 
// in a DataSet with the list of customers via the JDBC driver. 
// 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 = "jdbc:/usr/java/lib/RecitalJDBC/Recital/sql/RecitalDriver;"+
			"jdbc:Recital:Data Source=localhost;database=southwind";       
	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 Recital Southwind database. // It then retrieves all the customers via the JDBC driver. public void SelectCustomers() { // setup the Connection URL for JDBC String gateway = "jdbc:/usr/java/lib/RecitalJDBC/Recital/sql/RecitalDriver;"+ "jdbc:Recital:Data Source=localhost;database=southwind"; 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(); }
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If you want details about how storage devices are performing on Redhat/Centos/Fedora use the vmstat and iostat commands.

After installing Centos 5.3 the iostat command is not available. To install it use yum:

# yum install sysstat
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Subclipse is an Eclipse Team Provider plug-in providing support for Subversion within the Eclipse IDE. This plugin is required in order to use the recital eclipse workspace.
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I am pleased to finally report that the Centos release of Redhats 5.3 has been built and is available for download from http://www.centos.org/

The highlights of this release can be found at the following URL: http://www.redhat.com

The main areas of interest in my opinion excluding critical secirty fixes are:

  • Updated hardwaresupport support for the new Intel Core i7 (Nehalem) chips
  • Beefed up virtualiseation support increasing CPU and Ram limits of Virtual machines.
  • Inclusion of the fully open sourced OpenJDK. This makes Red Hat Enterprise Linux 5.3 the first enterprise-ready solution with a fully open source Java stack when combined with JBoss Enterprise Application Platform.


For those who already have Centos 5.2 installed you can simply receive the update via Yum.

Before you do the following, check that  you do not have 3rd party repo's and the Centos-testing repo enabled.

You can display the currently enabled repo's using the following command.

$ yum repolist



Then as root at the prompt type:

$ yum update

 

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A number of people have complained about data loss after a system crash when using Ext4.  A bug report was logged. According to multiple posts by a developer of Ext4, Theodore Tso, this is due to differences in approach to security and performance issues between the two file systems.

Ext3 commits writes to disk within approximately 5 seconds - Ext4 can take from 40-150 seconds.  In addition, if a system is using Ext3 and crashes before the commit takes place you will still have the previous contents of a file where under Ext4 the file will be empty.  Theodore Tso feels that this is a failure at the application level and that the file system is behaving as designed and as specified by the POSIX spec (which apparently does not specify what is supposed to happen when a system is not shut down cleanly).  His solution to the issue is to suggest proper use of fsync() and lists various scenarios/examples in post 54 of the bug report (linked above).  In addition he wrote a patch that recognize the rename() situation mentioned in his post 54 yet retains the normal Ext4 behaviors and performance in the majority of cases.  Also a more "proper" solution has been provided which allows the behavior of Ext3 to be retained under Ext4 by mounting it with alloc_on_commit.

A somewhat related topic is the use of on-board caching by hard drives.  This behavior can be modified on most drives by using hdparm.
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Recital Web: cookies, sessions, 64-bit Apache module: documentation update:

Recital Web Getting Started
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When using Recital on linux you can integrate your favorite linux shell commands and use then directly inside Recital using the alias command. This can be particularly useful when you ssh into a remote system and run recital. You can then issue linux commands without having to open another terminal session. Several aliased shell commands are predefined in /opt/recital/conf/config.db. You can add others to suit your needs.
 
On my system i have these commands aliased.
alias pwd  "? default()"
alias cp   "copy file "
alias mv   "rename "
alias rm   "erase "
alias ls   "run('ls $0')"
alias ps   "run('ps $0')"
alias grep "run('grep $0')"
alias cd   "set default to $1"
alias cls  "clear screen"
These commands can now be used inside the Recital command window just as you would use them at the linux prompt, including the ability to pipe commands together.
ls -l | grep .prg
ps -elf | grep db.exe
The run() function that is used to run the shell command as specified in the alias command will capture output and display it in a text viewer. If you want to run the command and display the contents full screen, then specify true as the third parameter to the run().
run("command", true, true) 
The arguments to run() are as follows.
Argument Description
1 the command line to run
2 True if output should be displayed in a text area (default True)
3 True if the output should be displayed full screen (default False)
 
The alias command handles parameter substitition.
Macro Description
$0 the command line following the command name
$1..$n the arguments given to the command
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The ShellEd plugin is a good shell editor for Eclipse
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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
-or-
Server
-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   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.

Using Gateways, you can transparently access the following local or remote data sources:

  • Recital
  • Oracle
  • ODBC (Server-side ODBC data sources)
  • JDBC (Server-side JDBC data sources)
  • ADO (Use this to connect to SQL Server and other Native Windows OLEDB data sources)
  • MySQL
  • PostgreSQL

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

Important
When 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();
}
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