This guide will assist you in setting up an rsnapshot backup server on your network. rsnapshot uses rsync via ssh to perform unattended backups of multiple systems in your network. The guide can be found on the centos website here.
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.
The 64bit port of Recital requires these libraries to allow access to 32bit Xbase and C-ISAM data files which are 32bit.
If you do not have these libraries installed you will either get a "can't find db.exe" or an "error loading shared libraries" when trying to run or license Recital.
Installing the ia32 shared libraries
Redhat EL 5 / Centos 5 / Fedora 10
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Insert the Red Hat Enterprise Linux 5 Supplementary CD, which contains the ia32el package.
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After the system has mounted the CD, change to the directory containing the Supplementary packages. For example:
cd /media/cdrom/Supplementary/
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Install the ia32el package:
rpm -Uvh ia32el-<version>.ia64.rpm
yum install ia32el
Ubuntu / Debian
sudo apt-get install ia32-libs
So, to create and configure Recital ODBC datasources, you need to use the Window 32 bit ODBC Data Source Administrator or Recital's own Recital Universal ODBC Manager (32-bit).
The Window 32 bit ODBC Data Source Administrator is %windir%\SysWOW64\odbcad32.exe.
The Recital Universal ODBC Manager (32-bit) can be accessed from the Control Panel (icon view).
Latest Development News
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sernet.de maintain the latest Samba releases in a yum repository, allowing for an easy and painless install or upgrade of Samba on your yum based Linux distribution.
To install the latest available Samba execute the following commands at the shell:
# cd /etc/yum.repos.d # wget http://ftp.sernet.de/pub/samba/experimental/centos/5/sernet-samba.repo # yum install samba
To upgrade an existing Samba install:
# cd /etc/yum.repos.d # wget http://ftp.sernet.de/pub/samba/experimental/centos/5/sernet-samba.repo ## Note: edit sernet-samba.repo and add the line "gpgcheck=false" otherwise ## it will not install as it is not signed
# yum update samba
Note: These steps will install the very latest build available at sernet.de.
If you require a less bleeding edge version of Samba, use the "tested" repo. This can be found at the following URL: http://ftp.sernet.de/pub/samba/tested/rhel/5
There's a nice article on IBM developerworks describing how to package software using RPM. You can read it here.
// declare an empty dynamic array
a = array()
// declare a simple dynamic array
a = array("barry", "recital", "boston")
foreach a as value
echo value
endfor
// declare an associative array
a = array("name" => "barry", "company" => "recital", "location" => "boston")
echo "length of a is " + len(a)
foreach a as key => value
echo "key=" + key + ", value=" + value
endfor